faster than light travel
Gordon D. Pusch
[NOTE: Since 'sci.physics.relativity' is now operational, five of the
seven newsgroups this thread is posted to are no longer appropriate venues.
'Followup-To:' has been set to 's.p.r' and the crackpot group... :-)]
In article <LJ4A8YAq...@sthbrum.demon.co.uk> Keith Stein
<sth...@sthbrum.demon.co.uk> writes:
> Anthony Potts <po...@cms1.cern.ch> writes
> >On Mon, 30 Sep 1996, Keith Stein wrote:
>
> >> Nope, you want c^2 = 1/(mu.epsilon), where mu is the permeability, and
> >> epsilon is the permittivity of the 'air' in M-M's laboratory.
> >
> >Not if you are trying to communicate with an actual physicist. C is the
> >speed of light in a vacuum, not the speed of light in a medium. Therefore,
> >you use the permittivity and permeability of the vacuum when expressing c.
>
> BUT IN A MEDIUM LIKE 'AIR',
> YOU MUST USE THE PERMITTIVITY AND PERMEABILITY OF THE 'AIR', MR.POTTS.
> FROM WHICH MAXWELL'S EQUATIONS GIVE THE VELOCITY OF E-M WAVES IN 'AIR',
> AND RELATIVE TO THAT 'AIR'.
> (witch, of course, you no doubt must know yourself, Anthony :-)
>
> >On Mon, 30 Sep 1996, Keith Stein wrote:
> >
> > No, because there ain't no vacuum nowhere,and certainly not in M-M's lab
Something Keith Stein has consistently neglected to note in his
``there ain't no such thing as vacuum'' rants, is that in order
for his concept of ``lab air as the E/M medium'' to work, Stein must
>> REJECT MAXWELL'S EQUATIONS << --- even in ``macroscopic'' form...
Maxwell's equations are NOT Galileo-invariant; to *force* them to be
Galileo-invariant, they must be substantially modified. For example,
at a =minimum=, all the time-derivatives must be replaced by *convective*
derivatives. Furthermore, the form that these modifications must take
is not uniquely determined; there is substantial ambiguity as to which
terms should be modified to include the velocity of the medium, as
shown by Thomas E. Phipps' many papers on ``Hertzian electrodynamics''
(Phipps is also a crackpot --- but unlike Stein, Phipps is a
=mathematically competent= crackpot... :-T). This ambiguity becomes
quite relevant when attempting to analyze ``neo-Fizeau'' experiments,
since in any ``real world'' Fizeau apparatus, the moving fluid must
=necessarily= have an inhomogeneous velocity-distribution...
Stein also neglects to note that in order for his ``there ain't no such
thing as vacuum'' rant to hold, at a *microscopic* level one will have
to replace even Phipps' ``Hertzian'' electrodynamics with some sort of
``neo-Ritzian'' or ``action-at-a-distance'' formalism. Since he insists
that the ``medium'' is relevant no matter *HOW* good the ``vacuum'' is
(Stein apparently does not understand the ``extinction length'' concept),
the ``dragging'' of radio-waves by the 500 km/sec velocity of the solar
wind would have produced an =EASILY= observable anomalous delay in the
Viking-probe transponder experiments. However, this anomalous delay
was =NOT= observed --- whereas the the predicted general-relativistic
effects were verified to high precision...
In summary: Stein's hypothesis will require substantial modifications
to even the =MACROSCOPIC= form of Maxwell's equations, and furthermore
has probably =ALREADY= been falsified by the Viking-transponder experiment...
-- Gordon D. Pusch <pu...@mcs.anl.gov>
But I don't speak for ANL or the DOE, and they *sure* don't speak for =ME=...
Gordon D. Pusch
In article <pDaWYQAk...@sthbrum.demon.co.uk> Keith Stein
<sth...@sthbrum.demon.co.uk> writes:
> "Gordon D. Pusch" <pu...@mcs.anl.gov> writes
> >
> >Something Keith Stein has consistently neglected to note in his
> >``there ain't no such thing as vacuum'' rants, is that in order
> >for his concept of ``lab air as the E/M medium'' to work, Stein must
> >>> REJECT MAXWELL'S EQUATIONS << --- even in ``macroscopic'' form...
>
> What nonsense! All i am saying is use the standard form of Maxwell's
> Equations in a medium. The velocity obtained from the permeability and
> permittivity of the medium, as given by Maxwell's Equations *is* the
> Velocity relative to the medium.
And if the ``medium'' is moving >inhomogeneously< --- as it does in the
Fizeau experiment ??? Just *which* velocity do you intend to use in
your ``wave equation'' --- the >local< one ??? Guess what --- you
> >Maxwell's equations are NOT Galileo-invariant; to *force* them to be
> >Galileo-invariant, they must be substantially modified.
>
> More nonesense! The normal wave equation applies in the frame of
> reference in which the medium is stationary. The case is completely
> analogous to the case of sound waves. You wouldn't say those were NOT
> Galileo-invariant would you Gordon ? The wave equation is of exactly the
> same form in both cases.
=NOT= if the medium is moving inhomogeneously !!! What one needs to do
if the acoustic medium is =FLOWING= is no longer obvious, and one has
to go back to first principles to determine what the CORRECT equations
should be.
Just because light and sound both obey ``analogous'' wave equations
does =NOT= imply light and sound behave ``analogously,'' Mr. Stein !!!
For example, one is a transverse wave, whereas the other is longitudinal.
Hence, light can be polarized, whereas sound can't --- even though they
obey ``analogous'' wave equations.
> >In summary: Stein's hypothesis will require substantial modifications
> >to even the =MACROSCOPIC= form of Maxwell's equations,
>
> Well my hypothesis Gordon, is that we apply the standard Maxwell
> Equations for transmission of an e-m wave 'in a medium'.
> (i am not adding anything at all to standard e-m theory)
If the ``medium'' moves inhomogeneously (as will any REAL WORLD medium!)
you can no longer unambiguously apply the ``standard'' Maxwell equations
in unmodified form, and still maintain Galileo invariance. And, as shown
by Thomas Phipps (who is, BTW, in YOUR camp, not Einstein's!), unless one
handles said modifications =VERY= carefully, you will violate certain
little, unimportant details like conservation of _charge_ and _energy_.
Now, just how =DO= you intend to cope with those ``little'' problems
with your hypothesis, Mr. Stein ???
> > and furthermore
> > has probably =ALREADY= been falsified by the Viking-transponder
> > experiment...
>
> So 90 years after Einstein's revolutionary hypothesis, you think that
> there may be some evidence that the standard e-m theory may be wrong.
> Well i really doubt that it is myself Gordon, but we really should know
> bye now.
===NO===. Re-read my post, Mr. Stein: I stated that =YOUR= revisionist
hypothesis as to how Maxwell's equations should be reinterpreted has
probably =ALREADY= been falsified by experiment, ===NOT=== Einstein's.
It is =YOUR= interpretation that will violate charge and energy conservation
in inhomogeneously flowing media, unless Maxwell's equations are modified.
By contrast, under Einstein's interpretation, the macroscopic equations
have =EXACTLY= the same form in both homogeneous and inhomogeneous media.
``Standard e-m theory'' is still in =VERY= good shape, thank-you-very-much !!!
Gordon D. Pusch
[An incompletely edited version of this msg was inadvertantly posted earlier]
In article <pDaWYQAk...@sthbrum.demon.co.uk> Keith Stein
<sth...@sthbrum.demon.co.uk> writes:
> "Gordon D. Pusch" <pu...@mcs.anl.gov> writes
> >
> >Something Keith Stein has consistently neglected to note in his
> >``there ain't no such thing as vacuum'' rants, is that in order
> >for his concept of ``lab air as the E/M medium'' to work, Stein must
> >>> REJECT MAXWELL'S EQUATIONS << --- even in ``macroscopic'' form...
>
> What nonsense! All i am saying is use the standard form of Maxwell's
> Equations in a medium. The velocity obtained from the permeability and
> permittivity of the medium, as given by Maxwell's Equations *is* the
> Velocity relative to the medium.
And if the ``medium'' is moving >inhomogeneously< --- as it does in the
Fizeau experiment ??? Just *which* velocity do you intend to use in
your ``wave equation'' --- the >local< one ??? Guess what --- you can't!
If the ``medium'' moves inhomogeneously (as will any REAL WORLD medium!)
you can no longer unambiguously apply the ``standard'' Maxwell equations
in unmodified form --- if only because the time and space derivatives in
them will create new terms proportional to the medium's velocity,
acceleration, divergence, vorticity, shear-tensor, etc. AND, as shown by
Thomas E. Phipps (who is, BTW, in YOUR camp, not Einstein's!), unless one
handles said modifications =VERY= carefully, you will violate certain
little, unimportant details like conservation of _charge_ and _energy_.
Now, just how =DO= you intend to cope with those ``little'' problems
with your hypothesis, Mr. Stein ???
> >Maxwell's equations are NOT Galileo-invariant; to *force* them to be
> >Galileo-invariant, they must be substantially modified.
>
> More nonesense! The normal wave equation applies in the frame of
> reference in which the medium is stationary. The case is completely
> analogous to the case of sound waves. You wouldn't say those were NOT
> Galileo-invariant would you Gordon ? The wave equation is of exactly the
> same form in both cases.
=NOT= if the medium is moving inhomogeneously !!! What one needs to do
if the acoustic medium is =FLOWING= is no longer obvious, and one has
to go back to first principles to determine what the CORRECT equations
should be.
Just because light and sound both obey ``analogous'' wave equations
does =NOT= imply light and sound behave ``analogously,'' Mr. Stein !!!
For example, one is a transverse wave, whereas the other is longitudinal.
Hence, light can be polarized, whereas sound can't --- even though they
obey ``analogous'' wave equations.
> >In summary: Stein's hypothesis will require substantial modifications
> >to even the =MACROSCOPIC= form of Maxwell's equations,
>
> Well my hypothesis Gordon, is that we apply the standard Maxwell
> Equations for transmission of an e-m wave 'in a medium'.
> (i am not adding anything at all to standard e-m theory)
You must =NECESSARILY= add new hypotheses RE: how the medium's velocity
enters into Maxwell's equations when it is flowing inhomogeneously.
As shown by Phipps, this is =NOT= a trivial exercise, and if done
improperly, can lead to violations of charge and energy conservation.
(Note that Maxwell was faced with =EXACTLY= this same problem
regarding the incompatibility of charge conservation with Faraday's
Law of Induction; he was =FORCED= to introduce a new hypothesis ---
the displacement current --- in order to reconcile the two...)
James Hannum
David L Evens wrote:
> Maxwell's Equations do not address what the 'medium' is. It was
> pressumed it was something that got labeled the 'ether,' and conducted
> light waves like air cunducts sound waves or water conducts water waves.
> Einstein proved that this undetectable medium is unnecessary, and that
> light waves actually propogate through the combined electromagnetic field
> without a medium of the kind mechanical waves (like sound) require.
I don't know if I would say Einstein proved anything.
It is more like, he _assumed_ that Maxwell's
Equations were valid in all frame's of reference.
From this follows the consistance of the speed
of light, and SR.
James
<I have referenced this response to sci.physics.relativity,
perhaps in a few messages it can be removed
from the sci.physics.particle newsgroup, and any
others to which it may not strickly apply>
David L Evens
James Hannum (jha...@ix.netcom.com) wrote:
: David L Evens wrote:
: > Maxwell's Equations do not address what the 'medium' is. It was
: > pressumed it was something that got labeled the 'ether,' and conducted
: > light waves like air cunducts sound waves or water conducts water waves.
: > Einstein proved that this undetectable medium is unnecessary, and that
: > light waves actually propogate through the combined electromagnetic field
: > without a medium of the kind mechanical waves (like sound) require.
: I don't know if I would say Einstein proved anything.
: It is more like, he _assumed_ that Maxwell's
: Equations were valid in all frame's of reference.
All the experimental evidence available supported Maxwell's equations
being correct for the macroscopic behaviour of light. Einstein had also
just proven that light energy wasn't transmitted as waves, so he had the
additional help of not having bagage about there being a medium for the
conduction of physical waves.
: From this follows the consistance of the speed
: of light, and SR.
: James
: <I have referenced this response to sci.physics.relativity,
: perhaps in a few messages it can be removed
: from the sci.physics.particle newsgroup, and any
: others to which it may not strickly apply>
--
---------------------------+--------------------------------------------------
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A pocket full of positrons,| But he certainly took us by surprise!"
A fission, a fusion, +--------------------------------------------------
We all fall down! | "Was anybody in the Maquis working for me?"
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Akhlesh Lakhtakia
Please continue this discussion in
SCI.PHYSICS.RELATIVITY and leave out the
other ngs.
Thanks.
goldbach wrote:
>
> Blair P Houghton <bl...@trojan.neta.com> wrote in article
> <52kggc$h...@trojan.neta.com>...
> > David L Evens <dev...@uoguelph.ca> wrote:
> > >
> > >The fact that the atoms are very much smaller than the wavelength of
> > >light implies that isolated atoms will not interact strongly with light.
> >
> > Which is another reason that the wave theory of light
> > holds no water.
> >
> Whether an atom or molecule will react with light depends upon the
> wavelength of the light.
> Larry
>
> > --Blair
> > "Nor does a duck's back. Jack Sarfatti
> > has a fascinating treatise on the
> > implications of this connection."
> >
--
Akhlesh Lakhtakia (AX...@PSU.EDU; Tel: +1-814-863-4319; Fax:
+1-814-863-7967)
Department of Engineering Science and Mechanics, 227 Hammond
Building,
Pennsylvania State University, University Park, PA
16802-1401, USA
http://www.esm.psu.edu/HTMLs/Faculty/ALakhtakia.html
James Hannum
David L Evens <dev...@uoguelph.ca> wrote in article
<5392gl$m...@ccshst05.uoguelph.ca>...
> No, the acceleration we label as gravity is caused by our constantly
> changing geodesics. If we didn't accelerate, we'd be in free fall.
Actually, you can be undergoing constant acceleration
and be in free fall, orbit for example. It is just that
the acceleration is at a right angle to the velocity.
Paul Cuni
whats' the bottom line on this faster than light travel yes or no?
Karen M Cramer
Kevin Moore (kev...@okoboji.com) wrote:
: > whats' the bottom line on this faster than light travel yes or no?
: So far as I know, they have gotten particles up to 99.9% of the speed of
: light in accelerators, but they have yet to break that barrier. The math
: behind the barrier is also fairly solid: You can't increase the velocity of
: a body with a mass approaching infinity, (at least not with anything we
: have now.)
: But always remember, for a long time the idea of breaking the sound barrier
: was equally absurd.
Before they managed to get planes to break the sound barrier they
knew that other things did like when you crack a whip. Nothing goes
faster than the speed of light.
: The bottom line is there is no bottom line yet.
: (If anything I have said is somewhat or completely wrong, feel free to
: thrash me. I'm just a hobby physicist but I pretty confident in what I do
: know.)
: --
: Kevin Moore
: kev...@okoboji.com | bri...@rconnect.com
: "Among all creatures, humans are distinguished by the extent
: to which they wonder about things that do not immediately
: affect their subsistence."
Karen
Kevin Moore
> whats' the bottom line on this faster than light travel yes or no?
So far as I know, they have gotten particles up to 99.9% of the speed of
light in accelerators, but they have yet to break that barrier. The math
behind the barrier is also fairly solid: You can't increase the velocity of
a body with a mass approaching infinity, (at least not with anything we
have now.)
But always remember, for a long time the idea of breaking the sound barrier
was equally absurd.
The bottom line is there is no bottom line yet.
me...@cars3.uchicago.edu
In article <01bbb959$0ccb5260$4dfc90ce@moore>, "Kevin Moore" <kev...@okoboji.com> writes:
>
>> whats' the bottom line on this faster than light travel yes or no?
>
>So far as I know, they have gotten particles up to 99.9% of the speed of
>light in accelerators, but they have yet to break that barrier. The math
>behind the barrier is also fairly solid: You can't increase the velocity of
>a body with a mass approaching infinity, (at least not with anything we
>have now.)
>
>But always remember, for a long time the idea of breaking the sound barrier
>was equally absurd.
>
Mati Meron | "When you argue with a fool,
me...@cars.uchicago.edu | chances are he is doing just the same"
Roger Carbol
Karen M Cramer wrote:
> Kevin Moore (kev...@okoboji.com) wrote:
>: whats' the bottom line on this faster than light travel yes or no?
>: But always remember, for a long time the idea of breaking the sound barrier
>: was equally absurd.
As a general sort of rule, one should probably avoid comparing the
"sound barrier" (which is a silly sort of term, really) to the speed
of light. They are different in a number of underlying, fundamental
ways -- so much so that they really don't form useful metaphors for
each other.
Of course, if your intention is to obfuscate the issue, then by
all means, make any comparison you like...
Roger Carbol .. r...@col.ca
jw
In <01bbb959$0ccb5260$4dfc90ce@moore> "Kevin Moore"
<kev...@okoboji.com> writes:
>
>
>> whats' the bottom line on this faster than light travel yes or no?
>
of
>light in accelerators, but they have yet to break that barrier. The
math
>behind the barrier is also fairly solid: You can't increase the
velocity of
>a body with a mass approaching infinity, (at least not with anything
we
>have now.)
>
barrier
>was equally absurd.
No equally at all. There never was a fundamental physical
law forbidding that. Exceeding the light speed would,
among other things, be equivalent to going back
in time - which violates causality, since you could
then prevent the events that had already happened.
David Suarez de Lis
Marco Mark-1 Nelissen wrote:> : : > whats' the bottom line on this faster than light travel yes or no?
> : : So far as I know, they have gotten particles up to 99.9% of the speed of
> : : light in accelerators, but they have yet to break that barrier. The math
> : : behind the barrier is also fairly solid: You can't increase the velocity of
> : : a body with a mass approaching infinity, (at least not with anything we
> : : have now.)
> : : But always remember, for a long time the idea of breaking the sound barrier
> : : was equally absurd.
>
> : knew that other things did like when you crack a whip. Nothing goes
> : faster than the speed of light.
>
> in the sense of going somewhere via some sort of 'shortcut', giving the impression
> that you travelled faster than light, even though you never reached c.
> (although I wish someone would explain to me why some people categorically refuse
> to accept any form of faster than light travel, even though there appear to be
> 'tricks' that would allow it, without violating causality in any way.)
>
> Marco
As a matter of fact, even classically (I mean non-quantum-lly) General
Relativity doesn't forbids FTL particles, just forbids particles
'jumping' the speed of lifgt barrier (a real barrier as someone said,
very different from sound or other barriers)
But as QED (Quantum ElectroDynamics) shows us, even light may go faster
than light. As light speed is an 'average' value, and in short
distances, there are many shorter paths where a photon (real or virtual)
may move faster than c... Even virtual particles, not only photons, may
and indeed move FTL..
On the classical problem, it arises that a FTL particle (wrt a slower
than light reference system) will never appear as a simple particle: ie.
a FTL electron, for another FTL particle may seema dot, but for us will
be a bilobuled cone, infinite in extension and moving very fast... how
do we measure somethimng like that? That's the problem...
David@
--
David Suarez de Lis
Physics Faculty, University Santiago de Compostela, SPAIN
Craig DeForest
Karen M Cramer wrote:
> Before they managed to get planes to break the sound barrier they
> knew that other things did like when you crack a whip. Nothing goes
> faster than the speed of light.
Well, in the context of sonic-boom-like phenomena, that's not strictly
true. Lots of things can go faster than the speed of light *in a
particular medium*. It's the speed of light *in vacuo* that you can't
classically exceed. An example is high energy beta particles
(fast-moving electrons) emitted by nuclear reactor cores. The
electrons move faster than the speed of light through water, causing
the electromagnetic equivalent of a sonic boom -- Cerenkov radiation.
Marco Mark-1 Nelissen
Karen M Cramer (kmc_...@gwis2.circ.gwu.edu) wrote:
: Kevin Moore (kev...@okoboji.com) wrote:
: : > whats' the bottom line on this faster than light travel yes or no?
: : So far as I know, they have gotten particles up to 99.9% of the speed of
: : light in accelerators, but they have yet to break that barrier. The math
: : behind the barrier is also fairly solid: You can't increase the velocity of
: : a body with a mass approaching infinity, (at least not with anything we
: : have now.)
: : But always remember, for a long time the idea of breaking the sound barrier
: : was equally absurd.
: Before they managed to get planes to break the sound barrier they
: knew that other things did like when you crack a whip. Nothing goes
: faster than the speed of light.
Which doesn't exclude the theoretical possibility of "faster than light travel",
me...@cars3.uchicago.edu
In article <326277...@urania.nascom.nasa.gov>, Craig DeForest <zo...@urania.nascom.nasa.gov> writes:
>Karen M Cramer wrote:
>> Before they managed to get planes to break the sound barrier they
>> knew that other things did like when you crack a whip. Nothing goes
>> faster than the speed of light.
>
>true. Lots of things can go faster than the speed of light *in a
>particular medium*. It's the speed of light *in vacuo* that you can't
>classically exceed. An example is high energy beta particles
>(fast-moving electrons) emitted by nuclear reactor cores. The
>electrons move faster than the speed of light through water, causing
>the electromagnetic equivalent of a sonic boom -- Cerenkov radiation.
At the risk of becoming considered as a bore I'll repeat something
I've stated at least half a dozen times within the last year:
1) When the term "speed of light" with no qualifiers is used it
always means the same thing, i.e. speed of light in vacuum.
2) Since there is nothing special or magical about visible light,
when we talk loosely about "speed of light" we really mean "speed of
EM radiation". Now, there is no such thing as "speed of EM radiation
in matter". You can only talk about speed of EM radiation of specific
wavelength in matter and the value you get is wavelength dependent.
Those high energy betas you mention exceed the speed of visible light
in water but no matter how fast they're you'll always get EM radiation
that moves faster yet. Just pick a high enough frequency.
Sorry if it sounds nitpicking, but I noticed that this issue keeps
confusing people.
Wayne Throop
:: whats' the bottom line on this faster than light travel yes or no?
That's the bottom line alright; yes or no.
: "Kevin Moore" <kev...@okoboji.com>
: So far as I know, they have gotten particles up to 99.9% of the speed
: of light in accelerators, but they have yet to break that barrier.
: The math behind the barrier is also fairly solid: You can't increase
: the velocity of a body with a mass approaching infinity, (at least not
: with anything we have now.)
Reasonable.
: But always remember, for a long time the idea of breaking the sound
: barrier was equally absurd.
No, this just won't do. The idea of breaking the sound barrier
was *never* equally absurd. There are quite definitely in a
different class. For significant point makes the cases differ,
at the time there was any aerodynamic math behind the "sound barrier",
supersonic projectiles were already known. The only question was,
could a human-carrying craft be engineered to do what it was
already known that bullets did. In the case of lightspeed,
there are no known examples at all. A very distinct difference.
Secondly, the math involved in the sound barrier was about things like
air pressure and so on; it was clear that these are finite, and the
singluarities false (not the least because of the point above: objects
were known that exceeded soundspeed). The math behind the lightspeed
"barrier" is much more akin to that behind the "limit" that prevents you
from making a perpetual motion machine. Both are based on fundamental
invariants arrived at via generalization, unlike aerodynamics, which
is an offshoot of kinematic gas theory (more or less).
So, to say that notion of "breaking the lightspeed barrier" is "equally
absurd" to the notion of "breaking the sound barrier" is very misleading.
Lightspeed is a theoretical limitation.
That sound thang was more of an engineering limitation.
--
Wayne Throop thr...@sheol.org http://sheol.org/throopw
thr...@cisco.com
akl...@villagenet.com
On 13 Oct 1996 23:03:05 GMT, "Kevin Moore" <kev...@okoboji.com> wrote:
>> whats' the bottom line on this faster than light travel yes or no?
>So far as I know, they have gotten particles up to 99.9% of the speed of
>light in accelerators
Tardyons, of course. Tachyons have to be slowed to the speed of
light.
>(If anything I have said is somewhat or completely wrong, feel free to
>thrash me. I'm just a hobby physicist but I pretty confident in what I do
>know.)
Me too. :)
--
Al
Scott Ellsworth
In article <01bbb959$0ccb5260$4dfc90ce@moore>, "Kevin Moore"
>> whats' the bottom line on this faster than light travel yes or no?
>
<...>
>You can't increase the velocity of
>a body with a mass approaching infinity, (at least not with anything we
>have now.)
>
>But always remember, for a long time the idea of breaking the sound barrier
>was equally absurd.
I would phrase that a bit differently. The sound barrier was considered
impassable as an engineering problem in manned flight. No known physics
made it impossible, but no known materials science could produce a manned
craft. This differs from the lightspeed barrier in that we have some
rather strong physics that says it cannot be done. (I cannot produce a
reference, but I am told that cannon could produce a supersonic projectile
long before a manned craft ever made it. Anyone know for certain when the
first rifled long arms could produce a bullet that made that rather
disturbing crack noise?)
As always, new data, or a theory that is more elegant could well eradicate
this physics, but this is a theory problem, not a matter of engineering.
>The bottom line is there is no bottom line yet.
And likely never will be, but it is important to realize when a n alternate
theory is violating known egineering practice, vs. known physical theory.
Cheap fusion power is an engineering problem, FTL is a theory problem.
Scott
--
f...@deltanet.com
"You die, she dies, EVERYbody dies" - Heavy Metal
"When a great many people are unable to find work, unemployment results" -
Calvin Coolidge, attrib. by Stanley Walker, City Editor, p. 131 (1934)
David L Evens
James Hannum (jha...@ix.netcom.com) wrote:
: David L Evens <dev...@uoguelph.ca> wrote in article
Under GR, objects in orbit aren't accelerating. It's one of the more
peculiar seeming bits of GR, but it makes perfect sense once you get your
mind arround how gravity is represented in GR.
Erik Max Francis
Kevin Moore wrote:
> But always remember, for a long time the idea of breaking the sound barrier
> was equally absurd.
This is commonly quoted as a rationalization of why faster-than-light travel
might be possible, and as such, it is a totally horrible example.
The sound barrier never, ever was thought to be a fundamental limit on the
speed at which objects can travel. Things were already long known to travel
faster than sound: bullets, shockwaves (that's what they're defined as), and
something as monumentally mundane as the tail of a whip.
It was an engineering difficulty to build craft that were capable of
withstanding the stresses induced on a plane when approaching the sound
barrier. There's a difference between what was at one time a technological
barrier (the sound barrier) and what is theoretically and experimentally a
fundamental physical barrier (the speed of light).
--
Erik Max Francis | m...@alcyone.com
Alcyone Systems | http://www.alcyone.com/max/
San Jose, California | 37 20 07 N 121 53 38 W
&tSftDotIotE | R^4: the 4th R is respect
Bruno Fabre
In article <329563ec...@news.concentric.net> pc...@cris.com (Paul Cuni) writes:
>From: pc...@cris.com (Paul Cuni)
>Subject: Re: faster than light travel
>Date: Sun, 13 Oct 1996 03:37:38 GMT
>whats' the bottom line on this faster than light travel yes or no?
I recently heard on the news a story about the discovery of some exotic
particles that could expand and contract space. They suggested that if some
contracting-space particles were placed at the front of a spaceship and some
expanding-space particles placed at the rear then the spaceship could travel
faster than light.
Does anyone know anything about this?
Matt R. Walkowiak
Bruno Fabre <bru...@tattersalls.com.au> wrote in article
<brunof.24...@tattersalls.com.au>...
Does this have anything to do with putting a buttered piece of bread on the
back of a cat, therefor making the cat float?
sorry :)
Matt
Jeff Greason
In article <53sv1h$c...@news.xs4all.nl>, mar...@xs2.xs4all.nl (Marco "Mark-1"
Nelissen) writes:
|> Which doesn't exclude the theoretical possibility of "faster than light
|> travel", in the sense of going somewhere via some sort of 'shortcut', giving
|> the impression that you travelled faster than light, even though you never
|> reached c. (although I wish someone would explain to me why some people
|> categorically refuse to accept any form of faster than light travel, even
|> though there appear to be 'tricks' that would allow it, without violating
|> causality in any way.)
Your premise is flawed. Yes, there are some "tricks" or "loopholes" in
presently understood physics which would appear to permit "apparent" FTL
travel. Most of them are understood to be mathematical artifacts of
non-physical conditions, but a few of them (tunneling & Thorne-type
wormholes, for example), may be physically attainable by a suitably advanced
technology.
However, to the best of our current understanding, *all* of these tricks
violate causality as it is presently understood. That doesn't mean they're
impossible -- but it means that either our understanding of the physics
is wrong, or our definition of causality needs improvement. If you want an
opinion, my opinion is that our understanding of causlity is imperfect, but
the universe doesn't respect my opinion :-)
Disclaimer: While I am an Intel employee, all opinions expressed are my own,
and do not reflect the position of Intel, NETCOM, or Zippy the Pinhead.
============================================================================
Jeff Greason "We choose to go to the Moon in this decade,
<gre...@ptdcs2.intel.com> and do the other things, not because they
<gre...@ix.netcom.com> are easy, but because they are hard." -- JFK
Wayne Throop
: mar...@xs2.xs4all.nl (Marco "Mark-1" Nelissen)
: I wish someone would explain to me why some people categorically
: refuse to accept any form of faster than light travel, even though
: there appear to be 'tricks' that would allow it, without violating
: causality in any way.)
Well, categorically refusing to accept the possibility of FTL
is a rather severe position, but it's not all that arbitary, really.
The "tricks" that "would allow it" don't address the main
causailty problem, described at
http://sheol.org/throopw/tachyon-pistols.html
Basically, FTL does equal time travel if SR is even vaguely correct, and
though time travel may also be possible, and avoid causality problems,
lots of people just don't think time travel is a sensible notion,
and extend this distaste to FTL.
welshwytch
Jeff Greason wrote:
>
> In article <53sv1h$c...@news.xs4all.nl>, mar...@xs2.xs4all.nl (Marco "Mark-1"
> Nelissen) writes:
>
> |> Which doesn't exclude the theoretical possibility of "faster than light
> |> travel", in the sense of going somewhere via some sort of 'shortcut', giving
> |> the impression that you travelled faster than light, even though you never
> |> categorically refuse to accept any form of faster than light travel, even
> |> though there appear to be 'tricks' that would allow it, without violating
> |> causality in any way.)
>
> presently understood physics which would appear to permit "apparent" FTL
> travel. Most of them are understood to be mathematical artifacts of
> non-physical conditions, but a few of them (tunneling & Thorne-type
> wormholes, for example), may be physically attainable by a suitably advanced
> technology.
>
> However, to the best of our current understanding, *all* of these tricks
> violate causality as it is presently understood. That doesn't mean they're
> impossible -- but it means that either our understanding of the physics
> is wrong, or our definition of causality needs improvement. If you want an
> opinion, my opinion is that our understanding of causlity is imperfect, but
> the universe doesn't respect my opinion :-)
>
Our theories for describing spacetime
make assumtions that we don't even know are followed at small distances
scales. Such as the principle of equivalence.
An operational definition of the speed of light would involve
meauring tangents to the path traced by a massless particle.
But in general relativity "particle" is not a generally covariant
object, not when we do quantum theory in a general relativistic
background.
So these ideas have a great deal of MURK at their heart, and
unfortunately the parts of general relativity where the
murk needs to be cleared by obersvation are not accessible
to testing by today's research technology.
Quantum gravity is an excellent endeavor in physics to
poke fun at or search for social constructs being used like wild,
because there is so little possibility now of being guided
by observation, and the cultural quirks and cult-like behavior
among people in this field, including the major cult of which
I am an acolyte, string theory, is quite incredible to see.
Don't take anything any physicist say as absolute truth because
right now none of it can be tested. The math is fun but some guys
tend to take math as BEING reality rather than being yet
another language for attemtping to describe what we perceive
in the world around us.
Actually it is fairly inevitable in general relativity for
causality to break down in one way or another.
If we accept just working in general relativity forgetting
quantum theory etc then the Hawking-Penrose singularity
theoerems are basically just the statement:
Gravity eventually makes causality break down locally or globally.
Locally is the singularity inside a black hole. Globally is if
that singularity is naked and has no horizon, or if the
singularity is avoided by negative pressure making a wormhole.
General relativity kind of sucks in that way, which is why everyone
always is dreaming that there exists a COSMIC CENSOR to tell
it to shut up about all this shaky causality already!
;-)
Marco Mark-1 Nelissen
Wayne Throop (thr...@sheol.org) wrote:
: Basically, FTL does equal time travel if SR is even vaguely correct, and
: though time travel may also be possible, and avoid causality problems,
: lots of people just don't think time travel is a sensible notion,
: and extend this distaste to FTL.
I think I remember a theory which involved some sort of 'universal clock'
running the entire universe, preserving causality no matter what.
Is there any evidence for or against this theory?
Another question justed popped into my mind: it has been said here that
time-dilation has been observed in the decay of accelarated particles.
I was wondering if there was ever an experiment in which such particles where
accelerated (and showed time-dilation), and where subsequently decelerated
back to non-relativistic speeds.
Marco
Mark O'Leary
In article <542897$b...@news.xs4all.nl>,
Marco "Mark-1" Nelissen <mar...@xs2.xs4all.nl> wrote:
>Another question justed popped into my mind: it has been said here that
>time-dilation has been observed in the decay of accelarated particles.
>I was wondering if there was ever an experiment in which such particles where
>accelerated (and showed time-dilation), and where subsequently decelerated
>back to non-relativistic speeds.
>
>Marco
Virtually all ring-accelerator experiments end with the relativistic
particle beam being fired into a stationary target or detector. I guess
hitting a brick wall counts as 'decelerating to non-relativistic speeds'.
M.
--
-=-=-=-=-=- -.-. .- .-.. .-.. -- . -.-. --- --- ... .-.-.- -=-=-=-=-
Mark O'Leary, Voice: Extn. 6201
Network & Communications Group. Email: mol...@dmu.ac.uk
De Montfort University, UK.
Alan Bostick
gre...@ptdcs2.intel.com (Jeff Greason) writes:
>In article <53sv1h$c...@news.xs4all.nl>, mar...@xs2.xs4all.nl (Marco "Mark-1"
>Nelissen) writes:
>Your premise is flawed. Yes, there are some "tricks" or "loopholes" in
>presently understood physics which would appear to permit "apparent" FTL
>travel. Most of them are understood to be mathematical artifacts of
>non-physical conditions, but a few of them (tunneling & Thorne-type
>wormholes, for example), may be physically attainable by a suitably advanced
>technology.
>However, to the best of our current understanding, *all* of these tricks
>violate causality as it is presently understood. That doesn't mean they're
>impossible -- but it means that either our understanding of the physics
>is wrong, or our definition of causality needs improvement. If you want an
>opinion, my opinion is that our understanding of causlity is imperfect, but
>the universe doesn't respect my opinion :-)
Kip Thorne's wormhole-based time travel devices do not seem to violate
causality; at least it does not generate grandfather (Kip calls it "matricide")
paradoxes. He discusses the issue in his popular book, BLACK HOLES AND TIME
WARPS: EINSTEIN'S OUTRAGEOUS LEGACY.
He *does* warn, however, that a wormhole-based time machine would very likely
blow itself up in a fountain of amplified vacuum energy.
--
Alan Bostick | "Dole is so unpopular, he couldn't sell beer on
mailto:abos...@netcom.com | a troop ship." (Ohio Republican Senator William
news:alt.grelb | Saxbe on Bob Dole's early career in the Senate)
http://www.alumni.caltech.edu/~abostick
http://www.theangle.com/ The first site with a brain. Yours.
Robert. Fung
Paul Cuni wrote:
>
> whats' the bottom line on this faster than light travel yes or no?
I haven't seen any FTL's :)
1. It's unclear to me whether it's ruled out by SR for just
charged matter, all matter only, or including
*any* measurable.
2. Is the measurement of the one-way speed of c possible
without a signal with speed > c ?
3. If the one-way speed isn't measureable but a relative speed
is, then there must be a way to affect the path of the
measurable ?
4. A mathematical determination as Maxwell's might be possible
for some relations between measurables, but this implies
that we don't completely know the operating specs for
matter.
...
RICHARD J. LOGAN
I suggest you crack open a sophmore physics textbook to find the answers
to these questions.
Comment 1 betrays an enormous ignorence of basic relativity.
Comment 2 shows you haven't even looked at Halliday and Resnick.
Comment 3 sounds mighty important but Comments 1 and 2 indicate you need
to do a lot more studying.
Comment 4 sounds even more impressive than comment 3 but, again, the big
words don't hide the fact that you haven't taken freshman physics yet.
I apologize in advance for my nasty remarks but before you move on to the
tough questions you need a better understanding of the fundamentals.
--
___________________________________
Richard J. Logan, Ph.D.
University of Georgia Research Foundation, Inc.
Derek Sorensen
In article <542897$b...@news.xs4all.nl>
mar...@xs2.xs4all.nl "Marco "Mark-1" Nelissen" writes:
> I think I remember a theory which involved some sort of 'universal clock'
> running the entire universe, preserving causality no matter what.
> Is there any evidence for or against this theory?
>
Sorry, no answer to your question, but this reminds me of a question
I've been dying to ask ...
If time dilation occurs at relativistic speeds, and we know the universe
is expanding at great speed, does it then make sense to talk about how
old the universe is?
Derek Sorensen
--
Curiosity *may* have killed Schrodinger's cat.
Cody Saunders
akl...@villagenet.com wrote:
: Tardyons, of course. Tachyons have to be slowed to the speed of
: light.
someone was talking about tachyons to me once. said something about them
approaching the speed of light, then "disappearing" then reappearing when
they went below the speed of light once more.
where do they disappear to, and can anyone clarify this further?
on FLT: is it Solaris which defines c? maybe some special quality of
those who observe the universe from within the confines of this solar
system?
Dave Steffen
Marco "Mark-1" Nelissen (mar...@xs2.xs4all.nl) wrote:
> Another question justed popped into my mind: it has been said here
> that time-dilation has been observed in the decay of accelarated
> particles. I was wondering if there was ever an experiment in which
> such particles where accelerated (and showed time-dilation), and
> where subsequently decelerated back to non-relativistic speeds.
The detection of time dilation generally involves timing the
decay of some decay-prone particle; i.e. the particle moves farther
than it should, given its velocity and the decay time. Thus, it's hard
to slow the thing down because it doesn't exist any more. ;-)
If, however, if you were to manage such a thing (which is
certainly possible), it's not clear why you'd be doing it. A proton is
a proton, regardless of how fast it was going yesterday.
/\
\/
Dave Steffen Wave after wave will flow with the tide
Dept. of Physics And bury the world as it does
Colorado State University Tide after tide will flow and recede
stef...@lamar.colostate.edu Leaving life to go on as it was...
- Peart / RUSH
"If you live in interesting times, I pray the fact causes you no alarm"
- Frank Herbert
-----------------------------------------------------------------------
John August
: : > whats' the bottom line on this faster than light travel yes or no?
: : So far as I know, they have gotten particles up to 99.9% of the speed of
: : light in accelerators, but they have yet to break that barrier. The math
: : behind the barrier is also fairly solid: You can't increase the velocity of
: : a body with a mass approaching infinity, (at least not with anything we
: : have now.)
Well, the * acceleration * diminishes and the * interpretation * is that this
is due to increasing mass. But it could just as easily be due to decreasing
force.
Ritz explained the then known effects of fields on high speed particles in this
way.
: : But always remember, for a long time the idea of breaking the sound barrier
: : was equally absurd.
Mmmm .... I don't think there was a "speed limit" - its just that there
was the doubt any feasible technology could push you that fast. So not
equally absurd - but still very difficult.
: Before they managed to get planes to break the sound barrier they
: knew that other things did like when you crack a whip. Nothing goes
: faster than the speed of light.
Karen - I understand you clearly mean the speed of light in vacuum here.
Well, we can make nothing go faster than the speed of light at present
with present approaches, yes .....
But, consider the following situation : we fire shells out of cannons, get
them to a maximum possible speed, and then decide it is * physically
impossible * to move faster than this speed.
We're talking about a phantom barrier here.
When you accelerate particles by applying a force from something which
is receding behind at a speed approaching that of light, as with an
electron gun, it is like a cannon. The mass is constant, but the force
diminishes.
With a rocket, however, you are talking about entirely different physics.
The barrier is not there anymore.
: : The bottom line is there is no bottom line yet.
Yep - definitely.
It does depend on whether you embrace Relativity - but even with in the
framework of relativity, there are still fiddles you can do anyway - for
example, squeezing the space in front of you and explanding the space
behind you, in a General Relativistic sense (which is all nonsense anyway).
--
John August
The Ritzian alternative to Relativity -
Robert Coe
On Sun, 13 Oct 1996 03:37:38 GMT, pc...@cris.com (Paul Cuni) wrote:
: whats' the bottom line on this faster than light travel yes or no?
No.
--
___ _ - Bob
/__) _ / / ) _ _
(_/__) (_)_(_) (___(_)_(/_____________________________________ b...@1776.COM
Robert K. Coe ** 14 Churchill St, Sudbury, MA 01776-2120 USA ** 508-443-3265
atwi...@traveller.com
In <53sv1h$c...@news.xs4all.nl>, mar...@xs2.xs4all.nl (Marco "Mark-1" Nelissen) writes:
>Karen M Cramer (kmc_...@gwis2.circ.gwu.edu) wrote:
>: : > whats' the bottom line on this faster than light travel yes or no?
>: : light in accelerators, but they have yet to break that barrier. The math
>: Before they managed to get planes to break the sound barrier they
>: knew that other things did like when you crack a whip. Nothing goes
>: faster than the speed of light.
>
>in the sense of going somewhere via some sort of 'shortcut', giving the impression
>that you travelled faster than light, even though you never reached c.
>(although I wish someone would explain to me why some people categorically refuse
>to accept any form of faster than light travel, even though there appear to be
>'tricks' that would allow it, without violating causality in any way.)
I guess the reason is that wormholes and such gimmicks have never been
demonstrated to exist. However, more to your point, some professors have
suggested the fact that the image of scissor-blades can be shown to travel
faster than light as the intersection approaches the tips of the scissors.
In this case the image itself has no mass. The troublesome part is just
philosophical in that the image is travelling faster than the light that
carries the image.
I am looking for someone to explain this better than I. So feel free...
ATW
atwi...@traveller.com
In <3262a326...@news.villagenet.com>, akl...@villagenet.com writes:
>Tardyons, of course. Tachyons have to be slowed to the speed of
>light.
I was under the impression that tachyons went faster than light in their
medium by definition. If they were slowed down, then they would no longer
be tachyons. - I think.
ATW
David L Evens
atwi...@traveller.com wrote:
A tachyon is an particle which cannot travel at or slower than the speed
of light. With this limitation, it is perfectly possible to deduce
general properties of tachyons. These are interesting, but don't look
like likely candidates for any kind of useful applications, even if they
exist.
Richard Andrew Bryan
You are indeed correct. I read in an issue of "popular Mechanics" that
the speed of light is indeed a limit (in the sense of calculus) meaning
that the velocity can be approached from both sides but never reached. At
the speed of light mass becomes undefined or infinite. At subluminal
speeds mass is a positive quanitiy while at superluminal speeds, mass
becomes a negative quantity. The problem is that negative mass hass never
been found and that negative mass would imply negative energy. These
theories need more discussion.
Richard Bryan (MECH 9T7)
On 20 Oct 1996 atwi...@traveller.com wrote:
> In <3262a326...@news.villagenet.com>, akl...@villagenet.com writes:
> >Tardyons, of course. Tachyons have to be slowed to the speed of
> >light.
>
> I was under the impression that tachyons went faster than light in their
> medium by definition. If they were slowed down, then they would no longer
> be tachyons. - I think.
>
> ATW
>
>
>
me...@cars3.uchicago.edu
In article <Pine.SGI.3.91.961021...@skule.ecf>, Richard Andrew Bryan <bry...@ecf.toronto.edu> writes:
>You are indeed correct. I read in an issue of "popular Mechanics" that
>the speed of light is indeed a limit (in the sense of calculus) meaning
>that the velocity can be approached from both sides but never reached. At
>the speed of light mass becomes undefined or infinite. At subluminal
>speeds mass is a positive quanitiy while at superluminal speeds, mass
>becomes a negative quantity.
Not negative. Imaginary.
Christopher R Volpe
Richard Andrew Bryan wrote:
>
> You are indeed correct. I read in an issue of "popular Mechanics" that
> the speed of light is indeed a limit (in the sense of calculus) meaning
> that the velocity can be approached from both sides but never reached. At
> the speed of light mass becomes undefined or infinite. At subluminal
> speeds mass is a positive quanitiy while at superluminal speeds, mass
> been found and that negative mass would imply negative energy. These
> theories need more discussion.
Negative? I think you mean "imaginary".
--
Chris Volpe Phone: (518) 387-7766
GE Corporate R&D Fax: (518) 387-6560
PO Box 8 Email: vol...@crd.ge.com
Schenectady, NY 12301 Web: http://www.crd.ge.com/~volpecr
Jonas Mureika
In article <54chcd$h...@tsunami.traveller.com>, <atwi...@traveller.com> wrote:
>In <3262a326...@news.villagenet.com>, akl...@villagenet.com writes:
>>Tardyons, of course. Tachyons have to be slowed to the speed of
>>light.
>
>I was under the impression that tachyons went faster than light in their
>medium by definition. If they were slowed down, then they would no longer
>be tachyons. - I think.
>
>ATW
>
Yes, tachyons travel faster than light by definition; they are entirely
spacelike particles (i.e. exist outside the light cone, whereas all
normal particles exist within). Tachyons themselves cannot slow below
c. However, there has been some recent discussion of two distinct
issues which relate to what you suggest.
(1) Faster-than-light photons. An apparent contradiction by name, this
theoretical construction shows that the geometric optics approximation
in various topologies of high curvature (strong gravitational field)
can permit the velocity of photons to apparently exceed c.
(2) Superluminal particles. It has been proposed that all matter that
we know (well, not necessarily *all* matter) belongs to a class of
particles which must obey a maximal velocity, c. However, by showing
that the Minkowskian structure of local frames is not necessarily a
fundamental property of spacetime (i.e. the latter could be at heart
Galilean, and the universe a sine-Gordon function resting in this
space), it is possible to allow the existence of other classes of
matter which can have maximal velocities whihc exceed c. What this all
means is that there may be some particles zipping through the universe
with real masses that can travel faster than c, but not faster than some
limiting speed for them, say c_1 > c. These types of particles could
possibly explain things such as the whereabouts of dark matter. They
should not be confused with the Standard Model families of particles,
though (i.e. electrons, muons, taus, quarks, ...)
Jim Akerlund
Derek Sorensen wrote:
<snip>
> --
> Curiosity *may* have killed Schrodinger's cat.
Whose curiosity; the cat's, or the experimenter's?
Humanities understanding of the universe is't only weird, it's weirder
then you can imagine.
Jim Akerlund
Bill Frolik
In sci.astro atwi...@traveller.com wrote:
: However, more to your point, some professors have
: suggested the fact that the image of scissor-blades can be shown to travel
: faster than light as the intersection approaches the tips of the scissors.
: In this case the image itself has no mass. The troublesome part is just
: philosophical in that the image is travelling faster than the light that
: carries the image.
:
: I am looking for someone to explain this better than I. So feel free...
:
: ATW
Since you've brought up the scissors, I'd like to know what the reasoning
would be if the moving intersection *did* have mass. Let's say you have
this scissor-like mechanical system with two movable straight edges that
meet at an angle A. One edge, moving toward the other at the speed of
light, imparts a force on a bearing assembly (O) located at the intersection
of the two edges. Since the bearing is forced to ride along the second
edge, would it not be forced to move at velocity c/sin(A)?
A \ F \ MOVING
__(\ I \_________|____
__\ X \________|____
\ E \(O) |
\ D \ V c
\ \
This is like the sailboat moving faster than the wind by sailing at an
angle relative to the wind. How fast does it go if the wind is moving
at or near the speed of light?
- Bill
__________________________________________________________________
BILL FROLIK HEWLETT-PACKARD COMPANY
bi...@hp-cv.cv.hp.com Workstation Technology Division
http://cvuiwww.cv.hp.com/~bill 1010 NE Circle Blvd, M/S 524A
tel/541.715.4082 fax/541.715.6258 Corvallis, Oregon 97330 USA
David L Evens
Richard Andrew Bryan (bry...@ecf.toronto.edu) wrote:
: You are indeed correct. I read in an issue of "popular Mechanics" that
: the speed of light is indeed a limit (in the sense of calculus) meaning
: that the velocity can be approached from both sides but never reached. At
: the speed of light mass becomes undefined or infinite. At subluminal
: speeds mass is a positive quanitiy while at superluminal speeds, mass
: becomes a negative quantity. The problem is that negative mass hass never
: been found and that negative mass would imply negative energy. These
: theories need more discussion.
I was under the impression that some effects had been observed which,
according to our present models, should indicate negative energy densities.
: Richard Bryan (MECH 9T7)
: On 20 Oct 1996 atwi...@traveller.com wrote:
: > In <3262a326...@news.villagenet.com>, akl...@villagenet.com writes:
: > >Tardyons, of course. Tachyons have to be slowed to the speed of
: > >light.
: >
: > I was under the impression that tachyons went faster than light in their
: > medium by definition. If they were slowed down, then they would no longer
: > be tachyons. - I think.
: >
: > ATW
: >
: >
: >
Richard Ottolini
The current issue of Science, a respected journal, speculates on a FTL mechanism
on v. 274 p. 202. Apparently some escape clause in general relativity
(accelerating reference frames) compared to special relativity (constant velocity).
I haven't reviewed the equations myself, but am mystified by this Star Trek'ish
article in Science.
Christopher Michael Jones
Robert Coe (b...@1776.COM) wrote:
: On Sun, 13 Oct 1996 03:37:38 GMT, pc...@cris.com (Paul Cuni) wrote:
: : whats' the bottom line on this faster than light travel yes or no?
: No.
Not true. Travel Faster than the speed of light relative to another
object is impossible in SR (special relativity) where all space-time is
assumed to be flat (a simplifying but innacurate assumption). However,
in GR (general relativity) space time does not have to be flat (since it
isn't really, this is good). You can manipulate space-time (in GR) in
such a way that you _can_ actually go faster than the speed of light.
I'm not making this up either, you can read a description of FTL in
Science magazine's I believe 11 Oct issue. Anyway, anyone who says going
faster than the speed of light is "totally 100% absolutely impossible"
isn't thinking as scientifically as they should be. I'm not saying that
faster than light travel is easy or that it is even possible to construct
a device which can make it possible. All I'm saying is that FTL is
_permitted_ by the laws of physics as we know them.
Marcel
Hello, everyone!
I'm new to this (these?) newsgroup(s) and this is a discussion which interests me
greatly. Sorry to cross-post, but to those who don't get the feed of SOME of these
groups, they might not see my input (and consequently wouldn't get the responses).
I propose a question:
What about the "laws" of physics in an alternate univers or alternate dimension?
This is relative to the "hyper-space" or, maybe "warp-bubble" idea presented in so many
classic Sci-Fi adventures. It sounds like fantasy, but before you dismiss this notion,
read on...
Experiments have been done in electromagnetics. One experiment that comes to mind is the
famous "Philadelphia" Experiment. I know, it's been covered up by the government for a
long time, but the data gathered from this could be quite useful in furthering research
in the "possibility" of c+ travel. If a way to "drop out", if you will, of this
"universe" were possible, then would not we be able to attain c+ travel? The other
possibility would be that we would not be travelling faster than light, but, rather,
utilize space curvature to get to where we want to go. In essence, "hyper-space".
Does anybody know of any results of this kind of experiments?
Marcel
Robert. Fung
Richard Andrew Bryan wrote:
>
> You are indeed correct. I read in an issue of "popular Mechanics" that
> that the velocity can be approached from both sides but never reached. At
> the speed of light mass becomes undefined or infinite. At subluminal
> speeds mass is a positive quanitiy while at superluminal speeds, mass
> becomes a negative quantity. The problem is that negative mass hass never
In Einstein's 1905
SR paper, he develops the coordinate transforms first,
and gets the length and time dilations. This defines an
EM interferometry of space and time,
then
he asks "what happens to EM laws in these coordinates"
and gets the Doppler effects, aberration, intensity
relations.
Then he says that since you can take any ponderable [neutral]
mass and put a small charge on it, the SR EM relations will hold
for neutral matter also. From this he gets the mass
dilation amd E=mc^2.
But does this only applies to a classical (composite) masses
since a neutron isn't a neutron when it's charged ?
> been found and that negative mass would imply negative energy. These
> theories need more discussion.
>
> Richard Bryan (MECH 9T7)
> On 20 Oct 1996 atwi...@traveller.com wrote:
>
> > In <3262a326...@news.villagenet.com>, akl...@villagenet.com
writes:
> > >Tardyons, of course. Tachyons have to be slowed to the speed of
> > >light.
> >
David L Evens
Marcel (mar...@javanet.com) wrote:
[Much snippage.]
: Experiments have been done in electromagnetics. One experiment that comes to mind is the
: famous "Philadelphia" Experiment. I know, it's been covered up by the government for a
: long time, but the data gathered from this could be quite useful in furthering research
: in the "possibility" of c+ travel. If a way to "drop out", if you will, of this
: "universe" were possible, then would not we be able to attain c+ travel? The other
: possibility would be that we would not be travelling faster than light, but, rather,
: utilize space curvature to get to where we want to go. In essence, "hyper-space".
: Does anybody know of any results of this kind of experiments?
They were TRYING to build a cloaking device. It worked well enough, but
was extremely harmful to life forms inside the field. No good.
iggy6
Robert Coe wrote:
>
> On Sun, 13 Oct 1996 03:37:38 GMT, pc...@cris.com (Paul Cuni) wrote:
> : whats' the bottom line on this faster than light travel yes or no?
>
> No.
> ___ _ - Bob
> /__) _ / / ) _ _
> (_/__) (_)_(_) (___(_)_(/_____________________________________ b...@1776.COM
> Robert K. Coe ** 14 Churchill St, Sudbury, MA 01776-2120 USA ** 508-443-3265
While it has been a long time (very) since I was a student of physics
and longer still since I was actually interested (thanks prof Rodman)I
will ask so I can learn. If a particle is drawn int a black hole, will
it not accelerate to beyond the speed of light before it actually
reaches the singularity? please support your stance as I generally am
considered a skeptic and don't believe anyone without proof of much.
(thanks Rev Baker)
Gordon D. Pusch
[NOTE: massive crossposting removed; 'Followup-To:' set to
'alt.sci.physics.new-theories']
In article <54rcao$r...@ccshst05.cs.uoguelph.ca> dev...@uoguelph.ca
(David L Evens) writes:
> Marcel (mar...@javanet.com) wrote:
> [Much snippage.]
> : Experiments have been done in electromagnetics. One experiment
> : that comes to mind is the famous "Philadelphia" Experiment.
> : I know, it's been covered up by the government for a long time,
[more snippage]
It wasn't ``covered up'' --- it >> NEVER HAPPENED.<<
The ``Philadelphia Experiment'' is an URBAN LEGEND; it was fabricated
whole-cloth, and perpetuated by UFO nuts and other conspiracy-theorists.
> : Does anybody know of any results of this kind of experiments?
No --- because it was NEVER PERFORMED.
> They were TRYING to build a cloaking device. It worked well enough,
> but was extremely harmful to life forms inside the field. No good.
Egad, Evens, not *you* too ??? Until now, I thought you were _rational_
(albeit arrogant and obnoxious). If this fool ``cloaking device''
actually =worked=, even on *inanimate* objects!,- then why didn't the
USA build a fleet of ``cloaked'' drone-ships for enemy-fleet annihilation
=DECADES= ago ??? Why aren't there ``cloaked'' drone-planes for
surveillance-purposes ??? Why weren't these ``extremely harmful'' effects
on ``life-forms'' weaponized ???
If =ANYTHING= like the ``Philadelphia experiment'' had ever =REALLY=
occurred, its applications would have leaked out a =LONG= time ago...
-- Gordon D. Pusch <pu...@mcs.anl.gov>
But I don't speak for ANL or the DOE, and they *sure* don't speak for =ME=...
Mad Scientist
In article <326f5ac7...@News.TIAC.NET>, Robert Coe <b...@1776.COM>
writes
>On Sun, 13 Oct 1996 03:37:38 GMT, pc...@cris.com (Paul Cuni) wrote:
>: whats' the bottom line on this faster than light travel yes or no?
>
>No.
Pay a visit to you local nuclear power station. Turn the lights off and
look down into the water. What do you see? Blue light, that's what.
The escaping electrons (et al) are travelling faster than the local
speed of light, hence, they "leave their EM field behind" --> blue
light.
Or did Paul mean "in a vacuum"? :-)
Prof.
,-----------------------------------+---------------------------. IS THERE
| Antigravity research and advanced | Colin F. Russ | ANY TEA
| time travel development committee | ru...@antigrav.demon.co.uk | ON THIS
`-----------------------------------+---------------------------' SPACESHIP?
jsnodgrass
Time dilation does not occur. This is a myth. Our time system is based
on space. Think about it; the atomic clock calculates how long it takes
an electron to travel from one point in space to another point in that
same space. This only tells us about time in our space. Relativity
assumes that the speed of light is constant in all space. Therefore, if
you go into some space that is compressed by gravity or some other
force, light would be the same speed, but only for you. If I saw that
light in your space, it is possible that the light would move slower
from where I was looking and therefore, I would measure time differently
for you than you would measure for yourself. This is due to the fact
that you are in a different type of space than me. Just examine the
perihelion(a type of circle) shift of mars. Relativity explains this
shift due to the fact that light travels from the sun to us but it goes
through different space which is warped by the gravity of the sun. When
the sunlight is reflected from mars, it looks like it is at xyz, but it
is really at some other xyz because the light that hits earth travels at
a constant speed and gets here earlier than we expect because space is
compressed near the sun... blah-blah-blah
jsnodgrass
Faster than light travel is not possible in a closed system. If you
consider looking at a particle from 1000000000 miles away, it is
conceivable to go faster than light, but if you look at it from 50ft
away at all times, it is not possible. Look, this rule of light isn't
only a rule for light, it is a property of space. If we want to
understand this universe, we need to look at space with relativity in
mind.
Akhlesh Lakhtakia
The only NG-Cyberspace with relativity "in mind" is
Sci.Physics.Relativity.
Please confine your musings to that NG. Don't clog
Sci.Physics.Electromag.
--
Akhlesh Lakhtakia (AX...@PSU.EDU; Tel: +1-814-863-4319;
Fax: +1-814-863-7967)
Department of Engineering Science and Mechanics, 227 Hammond
Building,
Pennsylvania State University, University Park, PA
16802-1401, USA
http://www.esm.psu.edu/HTMLs/Faculty/ALakhtakia.html
Telford Forgety
> (2) Superluminal particles. It has been proposed that all matter that
> we know (well, not necessarily *all* matter) belongs to a class of
> particles which must obey a maximal velocity, c. However, by showing
> that the Minkowskian structure of local frames is not necessarily a
> fundamental property of spacetime (i.e. the latter could be at heart
> Galilean, and the universe a sine-Gordon function resting in this
> space), it is possible to allow the existence of other classes of
> matter which can have maximal velocities whihc exceed c. What this all
> means is that there may be some particles zipping through the universe
> with real masses that can travel faster than c, but not faster than
some
> limiting speed for them, say c_1 > c. These types of particles could
> possibly explain things such as the whereabouts of dark matter. They
> should not be confused with the Standard Model families of particles,
> though (i.e. electrons, muons, taus, quarks, ...)
>
Perhaps this can be explained by a different class of superstring rather
than a whole new class of particle. If one imagines differently the
properties of the strings, one would have a set of standard-model particles
(quarks, taus, mous) that will be quite capable of FTL motion.
GLBRAD01
In article <3270B8...@citicorp.com>
our own universe? Where standing still was very close to moving at the
speed of light and moving through space very fast would be the equivalent
of our standing still (hypothetically standing still, that is)?
If matter can never get up to the speed of light from this side of the
mirror, and tachyons can never get down to the speed of light from the other
side of the mirror, then doesn't it stand to reason that everything there is
on both sides of mirror exists at the speed of light? Within the horizon of
light? As we exist right here on Earth within the horizon of Earth, a horizon
we can see but can never catch up to.
GLB
Christopher Michael Jones
On Sun, 27 Oct 1996, jsnodgrass wrote:
> Faster than light travel is not possible in a closed system. If you
> consider looking at a particle from 1000000000 miles away, it is
> conceivable to go faster than light, but if you look at it from 50ft
> away at all times, it is not possible. Look, this rule of light isn't
> only a rule for light, it is a property of space. If we want to
> understand this universe, we need to look at space with relativity in
> mind.
>
Oh, so I suppose you understand the way the universe works better
than all those scientists that write papers for peer reviewed
journals. I suppose it gives you a warm cuddly feeling in your
belly to know how smart you are doesn't it :-)
David L. Smith Jr.
abos...@netcom.com (Alan Bostick) writes:
>gre...@ptdcs2.intel.com (Jeff Greason) writes:
>>In article <53sv1h$c...@news.xs4all.nl>, mar...@xs2.xs4all.nl (Marco "Mark-1"
>>Nelissen) writes:
>>Your premise is flawed. Yes, there are some "tricks" or "loopholes" in
>>presently understood physics which would appear to permit "apparent" FTL
>>travel. Most of them are understood to be mathematical artifacts of
>>non-physical conditions, but a few of them (tunneling & Thorne-type
>>wormholes, for example), may be physically attainable by a suitably advanced
>>technology.
>>However, to the best of our current understanding, *all* of these tricks
>>violate causality as it is presently understood. That doesn't mean they're
>>impossible -- but it means that either our understanding of the physics
>>is wrong, or our definition of causality needs improvement. If you want an
>>opinion, my opinion is that our understanding of causlity is imperfect, but
>>the universe doesn't respect my opinion :-)
>Kip Thorne's wormhole-based time travel devices do not seem to violate
>causality; at least it does not generate grandfather (Kip calls it "matricide")
>paradoxes. He discusses the issue in his popular book, BLACK HOLES AND TIME
>WARPS: EINSTEIN'S OUTRAGEOUS LEGACY.
These types of time machines do violate the father paradoxes.
If one worm hole end is brought to a relativistic speed and dialated
in time, anyone from the forward time part of the hole could travle
back in to cause such a paradox, remember the dilation is only a local
effect for that end of the worm hole.
>He *does* warn, however, that a wormhole-based time machine would very likely
>blow itself up in a fountain of amplified vacuum energy.
>--
>Alan Bostick | "Dole is so unpopular, he couldn't sell beer on
>mailto:abos...@netcom.com | a troop ship." (Ohio Republican Senator William
>news:alt.grelb | Saxbe on Bob Dole's early career in the Senate)
>http://www.alumni.caltech.edu/~abostick
>http://www.theangle.com/ The first site with a brain. Yours.
Erik Max Francis
Digital Voodoo wrote:
> It simply means that you have to take into consideration the Imaginary
> Universe. The land where sqrt-1 and his friends hang out.
>
> Right?
No.
This is only one of many reasons pointing to the conclusion that
faster-than-light travel is impossible. The main objection is that, if a
particle travels faster-than-light, you can set up things such that
causality violations occur, or equivalently, that information is sent
backwards in time.
--
Erik Max Francis | m...@alcyone.com
Alcyone Systems | http://www.alcyone.com/max/
San Jose, California | 37 20 07 N 121 53 38 W
&tSftDotIotE | R^4: the 4th R is respect
"But since when can wounded eyes see | If we weren't who we were"
Kethas epetai-Khemara
akl...@villagenet.com wrote:
: On 13 Oct 1996 23:03:05 GMT, "Kevin Moore" <kev...@okoboji.com> wrote:
: >> whats' the bottom line on this faster than light travel yes or no?
: >So far as I know, they have gotten particles up to 99.9% of the speed of
: >light in accelerators
: Tardyons, of course. Tachyons have to be slowed to the speed of
: light.
: >(If anything I have said is somewhat or completely wrong, feel free to
: >thrash me. I'm just a hobby physicist but I pretty confident in what I do
: >know.)
From what I remember of my reading(Start SR in two weeks, apparently, so even *I* could be wrong on this ;),
something called the "Clarke corralary"(sp.?) is used, which is basically a quadratic curve, with velocity
along the x-axis and energy along the y-axis, whose 'hump' occurs at infinite energy and the speed of light,
then gradually becomes asymptotic with the x-axis. I'd try and draw it if I wasn't totally incompetent at ASCII
art ;)
As the previous poster mentioned, a tachyon has to be *slowed* to the speed of light. It is a mirror image of
this side of the curve; at zero energy it has infinite velocity, at infinite energy it travels at the speed of
light. This may even explain why none have been detected(Too fast for current detection techniques . . .). Or
have they?
Corrections welcome,
Wayne.
: Al
--
************************************************
* *
* From: Wayne Haley *
* a.k.a."Kethas epetai-Khemara" *
* < wm...@saturn.bton.ac.uk > *
* Homepage:http://www.comp.it.bton.ac.uk/~wmh1 *
*----------------------------------------------*
* "Malt does more than Milton can, *
* to justify Gods ways to man." *
* *
* -G. Benford. *
************************************************
Digital Voodoo
But isn't the problem really that nothing in the Real Universe can travel
faster than the speed of light? Isn't true that the only reason anyone
thinks that fsl travel is impossible the fact that at speeds past c, time
and distance become imaginary? Does this mean that it can't happen?
No.
It simply means that you have to take into consideration the Imaginary
Universe. The land where sqrt-1 and his friends hang out.
Right?
Ash---------------------------------------"It only hurts if you let it"
JUST SAY NO TO DRUMS!!!---Join the Partnership for a Drum Free Amerika
------------------------------------------------<dvo...@ix.netcom.com>
jsnodgrass <jsnod...@mho.net> wrote in article <32732E...@mho.net>...
Kevin Thomas
The "grandfather paradoxes" are actaully just erros of logic. There really
is no paradox when the logic errors are weeded out. As Kip Thorn pointed
out, if you are planning to go back in time tomorrow to kill you
grandfather 50 years ago, although you haven't experience the journey yet
yourself, as far as the universe is concerned, you have already completed
you actions in the past. So although you yourself do not know what is
going to happen when you get into the past, you may infer by the fact that
you are alive, as well as your grandfather, that for some reason on your
journey to the past you fail to kill him.
The logic error is putting "cause" before "effect" in a journey to the
past. In this situation, "effect" comes before "cause". In other words,
you actions have already been carried out before your decision to perform
them. So in the so-called "grandfather paradox" you know that regardless
of your intentions to kill your grandfather, for whatever reason, you will
fail to do so in your journey to the past.
David L. Smith Jr. <phy...@atlas.vcu.edu> wrote in article
<553u2i$l...@atlas.vcu.edu>...
Brad J Cadle
In article <01bbc62c$da817b00$7ec4abcf@default>,
Kevin Thomas <foo...@slip.net> wrote:
>The "grandfather paradoxes" are actaully just erros of logic. There really
>is no paradox when the logic errors are weeded out. As Kip Thorn pointed
>out, if you are planning to go back in time tomorrow to kill you
>grandfather 50 years ago, although you haven't experience the journey yet
>yourself, as far as the universe is concerned, you have already completed
>you actions in the past. So although you yourself do not know what is
>going to happen when you get into the past, you may infer by the fact that
>you are alive, as well as your grandfather, that for some reason on your
>journey to the past you fail to kill him.
>
>The logic error is putting "cause" before "effect" in a journey to the
>past. In this situation, "effect" comes before "cause". In other words,
>you actions have already been carried out before your decision to perform
>them. So in the so-called "grandfather paradox" you know that regardless
>of your intentions to kill your grandfather, for whatever reason, you will
>fail to do so in your journey to the past.
>
they didn't consider the scenario, but more that it implies that free will
is an illusion. For instance, let's say a video recorder records the actions
of a man from the future. IF at some future date the man views this recording
he knows that he will have to show up and perform those actions. The
information he just got cannot possible change that fact. in your scenario.
Hence we would be unable to commit suicide, or any other action he might
want to do to ensure that he does not go back in time. To take it one step
further, any time machine that is constructed could not freely allow
time travel to any point in the past at any place. If you had a stable
low gravity wormhole that send objects back in time five minutes into
the past, and you have been around it for 15 minutes, you cannot send
a bomb through to blow yourself up in the past. According to the scenario
described above something would prevent it from making it. Even if you
had a bomb that was timed based on the known rates of radioactive decay
it could not go off. yet if you suddenly recieved a deactivated bomb come
through the wormhole, it is still possible, and indeed must occur, that in five
minutes some action will happen that causes a deactivated bomb to be sent
through it. The worm hole is starting to sound rather selective.
If you had a worm hole such as this an you constantly tried to
throught things into it that would alter the past, something would happen
to prevent that from occuring everytime. It starts sounding as if
extremely improbable events would have to start occuring with a high
frequency. Now this may not be the case, but I think this is the source
of people's complaints with the resolution of the grandfather paradox
above. Granted, the scenarios I proposed are likely unrealistic, by it
is the implications of that scenario people have problems with.
-Brad
jw
In <01bbc62c$da817b00$7ec4abcf@default> "Kevin Thomas"
This hardly resolves the paradox.
For every thought experiment of changing retroactively
anything at all that is already on record - an unexplained
new factor, different in each case - "for whatever reason" - is
introduced to prevent the paradoxical result.
This is not good enough.
It begs the question. We already know that the
past can't be changed - because then the present
would be different - the question is *why*? For a special,
accidental, unknown reason in each case,
a *deus ex machina*? Or - a much neater explanation - because
a general, formal, analytical law of nature prohibits causality
to propagate from the present to the past? Occam's razor selects
the latter explanation, if it is possible.
In decent classical cases, it is: we have such a law:
the light speed limit. Cases involving singularities
(like wormholes) need to be
elaborated; but the end result, when and if the
theory is complete, must again be non-paradoxical
for any thought experiment - i.e. it must forbid
sending a signal to the past to change it -
in particular, forbid time travel.
Is there a natural, not *ad hoc* way, to
introduce such a prohibition? Apparently yes.
To quote from Kip Thorne's book
_Black Holes & Time Warps_, Chapter 14:
||"Hawking has a firm opinion on time machines.
||He thinks that nature abhors them, [...]
||Hawking suspects that the growing beam of vacuum
||fluctuations is nature's way of enforcing
||chronology protection: *Whenever one tries
||to make a time machine, and no matter what
||kind of device one uses in one's attempt
||(a wormhole, a spinning cylinder, a "cosmic
||string", or whatever), just before one's
||device becomes a time machine, a beam of
||vacuum fluctuations will circulate through
||the device and destroy it.*
||Hawking seems ready to bet heavily on this
||outcome.
||I am *not* willing to take the other side in
||such a bet. [...] My strong gut feeling is
||that I would lose this one. My own calculations
||with Kim, and unpublished calculations that
||Eanna Flanagan (a student of mine) has done
||more recently, suggest to me that Hawking is
||likely to be right. However, we cannot know
||for sure until physicists have fathomed in depth
||the laws of quantum gravity."
Robert. Fung
Erik Max Francis wrote:
>
> Digital Voodoo wrote:
>
> > It simply means that you have to take into consideration
> > the Imaginary Universe. The land where sqrt-1 and his friends
> > hang out.
> >
> > Right?
>
>
> This is only one of many reasons pointing to the conclusion that
> faster-than-light travel is impossible. The main objection is that,
> if a particle travels faster-than-light, you can set up
> things such that causality violations occur, or equivalently,
> that information is sent
> backwards in time.
>
A "project" determines the course of "actions".
The parameters of the project expectations as they
are intended to exist in the future,
are propagated through time
(mentally, virtually, neuralogically ?)
to provide a causual effect on our present actions.
Ripper
You are incorrect.
The quantom mechanics theory say that we can never know the exact speed and
direction of a partical.So, sometimes, a few particles CAN move faster than
light for a short period. This is also why black holes radiate photons,
like anything with temperture.
Ripper
I admit I'm also not a "professional" physicist but from what I know
Tachyons were never proven to exsist. They were made up as an attempt to
create particles that moved back in time. I don't think that any particle
moves normally beyond C but every particle can sometime do it (It explains
why black holes omit radiation).
Kethas epetai-Khemara <wm...@bton.ac.uk> wrote in article
<5557rv$f...@saturn.brighton.ac.uk>...
J. Matthew Nyman
This is interesting since I am still working towards understand the
Alcubierre warp drive paper. As I am sure everyone knows, this theory
postulates a type of motion that is never faster-than-light, and yet
gets something to a distant point in a faster-than-light fashion. So I
guess it depends on what you mean by "faster-than-light." Do you mean
is something really going faster than light or does it simply appear to
be doing so.
Also, as to the tachyons that I saw brought up. An interesting theory
was brought up in one of my classes about Erasmo Recami's "extended"
electromagnetic spectrum that allows the motion of superluminal
particles. This is being touted as "proof" that tachyons do exist, but
I do not know how valid the theory is.
John Torset
>You are incorrect.
>The quantom mechanics theory say that we can never know the exact speed and
>direction of a partical.So, sometimes, a few particles CAN move faster than
>light for a short period. This is also why black holes radiate photons,
>like anything with temperture.
I have read somewhere (possible stephen hawkins) that black holes radiates
photons because there are being created matter/antimatter along the
eventhorison, and before the matter/antimatter created can annhilate to energy
again they splitt apart, one particle goes into the black hole while the other
particle escapes and radiates photons.
<tsb>
<sb>John Torset
<sb>joh...@iceonline.com
Uwe Lauth
On Sat, 2 Nov 1996, J. Matthew Nyman wrote:
> This is interesting since I am still working towards understand the
> Alcubierre warp drive paper. As I am sure everyone knows, this theory
I'm one of those who don't know yet :-)
Can someone tell me where to find this paper?
Thanks
Uwe Lauth
Rick Ellis
Steve Gilham
> > This is interesting since I am still working towards understand the
> > Alcubierre warp drive paper. As I am sure everyone knows, this theory
> I'm one of those who don't know yet :-)
> Can someone tell me where to find this paper?
http://www.astro.cf.ac.uk/local/groups/relativity/papers/abstracts/miguel94a.html
-- Personal mail to steve*windsong.demon.co.uk (for which PGP is preferred) --
Steve Gilham |GDS Ltd.,Wellington Ho. |My opinions, not those of GDS
Software Specialist|East Road, Cambridge |Corporation or its affiliates.
steveg@ |CB1 1BH, UK |---------------------------------
uk.gdscorp.com |Tel:(44)1223-300111x2904|http://www.windsong.demon.co.uk/
Eric Kniffin
Ripper wrote:
>
> I admit I'm also not a "professional" physicist but from what I know
> Tachyons were never proven to exsist. They were made up as an attempt to
> create particles that moved back in time. I don't think that any particle
> moves normally beyond C but every particle can sometime do it (It explains
> why black holes omit radiation).
Actually, I don't think that black holes have been proven to exist either.
Aren't they are just the best explanation so far for some weird radiation we
encounter? Or the logical result of a star's life cycle? (That is, if our
theories about how stars actually work are correct.)
-Eric "Nowhere NEAR a professional physicist" Kniffin
Eric Kniffin
Well, I don't know much of anything about the theory of relativity, or
anything else dealing with this stuff. I'm only going to comment on the
observable results of all of this.
As I see it, there are two possible answers:
1-Time travel is not possible. We don't have any evidence of any
time-travellers from our future. And I don't believe that it could ever be
kept in total secrecy. I imagine that there will always be bad guys who want
to come back and rule the world, and we'd know about them.
2-In answer to "We already know that the past can't be changed - because then
the present would be different - the question is *why*?", we DON'T know this
at all. There was a science-fiction book called "Thrice Upon A Time", where
a guy figured ot how to send information back a few minutes in time to
himself. Those who received that information acted on it, and changed
everything from the moment they received the information onward. They talked
about what they called the "Superobserver", who existed outside of
time/space/reality. The superobserver would see things happen. Then it
would see the information being sent back in time. Then it would see the new
reality forming from the moment that the informatin was received.
This could be what is happening all the time for us. We think that Hitler
was a monster. But maybe something worse happened, people went back in time
to change it, and Hitler was the result. Maybe the "previous" problem was
so much worse that they didn't bother to go back and do away with Hitler.
Maybe they've tried to change things a billion times, and Hitler was the
least evil of all the outcomes. (Maybe something bad MUST happen
occasionally)
me...@cars3.uchicago.edu
that fit with the hypothesis that black holes exist. There are no
observed phenomena that fit with the tachyon hypothesis.
Mati Meron | "When you argue with a fool,
me...@cars.uchicago.edu | chances are he is doing just the same"
Doug Craigen
Eric Kniffin wrote:
>
> jw wrote:
> >
> > In <01bbc62c$da817b00$7ec4abcf@default> "Kevin Thomas"
> > <foo...@slip.net> writes:
> > >
> > >The "grandfather paradoxes" are actaully just erros of logic. There
The "grandfather paradoxes" are for wimps. Anybody with guts would go back
and kill themself. The grandfather parodox has me terrified to encourage my
kids to follow my footsteps in physics. If I start up a dynasty of
physicists, I increase the odds of being bumped off as a part of somebody's
thesis research.
My favorite of these is to arrange a completely mechanical situation, such as
a pair of worm holes such that a ball goes into one, enters the second at the
end, and comes out the other at the right time to knock itself out of going
into the first one. No spilled guts, but a paradox nevertheless.
|++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++|
| Doug Craigen |
| |
| If you think Physics is no laughing matter, think again .... |
| http://cyberspc.mb.ca/~dcc/phys/humor.html |
|++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++|
Cody Saunders
Eric Kniffin (lao...@warwick.net) wrote:
: This could be what is happening all the time for us. We think that Hitler
: was a monster. But maybe something worse happened, people went back in time
: to change it, and Hitler was the result. Maybe the "previous" problem was
: so much worse that they didn't bother to go back and do away with Hitler.
: Maybe they've tried to change things a billion times, and Hitler was the
: least evil of all the outcomes. (Maybe something bad MUST happen
: occasionally)
Not only the least evil, but the best possibility. It comes back to
personal subjectivity, in my opinion. My present situation requires that I
believe that Hitler existed and did the best job that he could. It also
requires me to believe that those who fought Hitler did the best job,
Hiroshima was the best solution, etc. It is about _your_ life that all
these theories fall back upon. I don't mean to imply the relativity
philosophy which probably led to Hitler (as an incorrect understanding of
Einstein's theories, and all), but there is something in near death
experiences (not the kind where you see the light, this is a Christianized
pre-programmed response, dream-like in the brain and stored in memories
right before the brain shuts down momentarily for your reboot), which
gives me the sense of utmost importance. My ego is as big as the
universe, and ever-expanding.
The point then on time travel is that it is possible. I would go as far as
to say I have received messages confirming this, but don't want to come
off loopy (who isn't these days, all days?). I will know sometime next
year what the message was intended to be interpreted as, and who sent it.
I believe it was myself, and I believe it was love her.
Wayne Hayes
In article <327FA3...@warwick.net>,
Eric Kniffin <lao...@warwick.net> wrote:
>2-In answer to "We already know that the past can't be changed - because then
>the present would be different - the question is *why*?", we DON'T know this
>at all. There was a science-fiction book called "Thrice Upon A Time", where
>a guy figured ot how to send information back a few minutes in time to
>himself. Those who received that information acted on it, and changed
>everything from the moment they received the information onward. They talked
>about what they called the "Superobserver", who existed outside of
>time/space/reality. The superobserver would see things happen. Then it
>would see the information being sent back in time. Then it would see the new
>reality forming from the moment that the informatin was received.
But this reduces to the same paradox. If, say, the guy gets mugged and
then sends himself a message back in time saying "don't turn left into
that dark alley down the street 2 minutes from now", and then gets the
message, and doesn't turn down the alley, then... who sent it? Certainly
not the same guy who DIDN'T turn into the alley, because he never turned
into the alley, and so didn't get mugged, and so didn't send the message.
Well, then, who DID send the message? And what happened to the entire
universe belonging to the guy who DID send the message? Did it cease
to exist? When did it cease to exist? The moment he sent the message,
or the moment (5 minutes previous) that the message is recieved.
Time travel may not be impossible, but if it does occur, it's almost
certainly not possible to change *anything* in the past --- at least not
in the same universe that you're doing the travelling in.
--
"Unix is simple and coherent, but it takes || Wayne Hayes, wa...@cs.utoronto.ca
a genius (or at any rate, a programmer) to || Astrophysics & Computer Science
appreciate its simplicity." -Dennis Ritchie|| http://www.cs.utoronto.ca/~wayne
Eric Kniffin
Yes, your "can't change anything in the past" scenario is certainly another
possibility. And it takes care of the paradox problems nicely. But I don't
think that anyone can travel to the past and NOT change it. Just being
there, without doing anything, will change things. If you just stand on a
street corner observing, someone will have to step out of the way to avoid
you. So maybe they step into the path of a car. Or maybe someone says "Hi"
to you. Not wanting to get into a conversation that somehow changes that
person, you don't respond. Wondering what makes rude people rude, they get
interested in human behavior. And there's the movie (or Twilight Zone
episode?) where the time traveller steps on a prehistoric butterfly. Which
would have fed some animal. The animal starves, as does the caveman who
would have ate that animal. Maybe you kill a mosquito that was destined to
start a malaria epidemic.
My point is that we don't need to intentionally change things, but I
don't see you it can be avoided. So either time travel is changing things
all the "time", and we can't possibly be aware of them, or there is no time
travel. Personally, I think that it's a fun fantasy. Great for sci-fi.
There have been scientific theories that seemed obvious, but did not actually
work. I think that's what we're dealing with here. Believing in it is a
huge leap of faith.
Chris
Hi. With regard to the "killing your grandfather" paradox, why
is it assumed that if one were to go back in time and kill
one's own grandfather, the effects of that action would propogate
instantaniously and bite you on the rump? Sime we are moving
through time at a specific, and appearently constant rate, would
you not expect the changes, ie no Dad, no conception, no you,
to propogate at that same rate, and therefore never catch up to
you, and therefore never erase you. The time line would overwrite
or split, meaning after a period of time, you could never
go home.
Just a thought,
Chris
--
43 Preston Dr. Dr. Christopher Fortin hackings just another
Wickford R.I. 02852 ch...@omega.mit.edu word for nothing
quakeID:nitrof http://users.ids.net/~fortin left to kludge.
WAPPLER FRANK
Chris Fortin asked:
> Hi. With regard to the "killing your grandfather" paradox, why
> is it assumed that if one were to go back in time and kill
> one's own grandfather, the effects of that action would propogate
> instantaniously and bite you on the rump?
Past effects propagate instantaneously through their `histories' or
`appropriate slices of space-time' as conserved quantities (family pictures
come to mind ...), w.r.t. them the slices are perfectly isolated.
However, we also observe that certain quantities are not conserved (space
coordinates of objetcs/entities as measured at local time, e.g. whether or not
some picture faces the wall - once everybody agrees which side the face is).
(in doubt: my `Ma', not your `Ma' :)
Occasionally I go back in time to meet my `secret grandfather'. The guy's
a total `wooden klutz' and usually kinda freaks me out, so I sh...ake my head
(off &).
Mysteriously/fortunately other people usually insist that I have not.
Go figure ... (not to pieces :).
Frank W ~@) R
Whatever in not forbidden in Physics is mandatory.
(after R. Feynman)
> Just a thought
Kevin Thomas
But see, you are not changing the past when you stand on the street corner,
because you were always there. It's not like the past existed once without
you in it, and then you went back in time, and now the past is rerunning
with you in it. Remember, you stood on that street corner BEFORE you went
back in time, from the universe's perspective. It's only from your
perspective does standing on the corner come after you make the trip
through time. You're not changing anything because you were there the
first (and only) time through. You were part of what happened.
It's really very simple once you understand it, and all these "thought
experiments" just crumble away. I am able to explain this rather
successfully in person, however, I am somewhat poor at communicating these
ideas "on paper". So I'm afraid, through my own fault, that I will
probably not have cleared anything up for anyone.
Dan Crispin Matthew Brown
Wayne Hayes (wa...@cs.toronto.edu) wrote:
: But this reduces to the same paradox. If, say, the guy gets mugged and
: then sends himself a message back in time saying "don't turn left into
: that dark alley down the street 2 minutes from now", and then gets the
: message, and doesn't turn down the alley, then... who sent it? Certainly
: not the same guy who DIDN'T turn into the alley, because he never turned
: into the alley, and so didn't get mugged, and so didn't send the message.
But the person he is sending the message to who didn't end up getting
mugged is not him as he is now. He will still have gotten mugged whether
he sends the message to prevent himself from getting mugged in the past.
I've read through this thread and it seems people are assuming that there
is only one timeline. If you go back into the past to change an event
which will affect your current future, then you would be disassociating
yourself from your current timeline and placing yourself into the one you
created by changing the event. The problem is however that if you do this
you will a) not be able to get back to your own future. You will be stuck
existing with another self for the rest of your life because that self
will never have to go into the past now to change that event. or b) you
will go into the future, but since it wont be your future you may have the
perfect oportunity to kill off yourself (since he wont be going anywhere
anytime soon) and replace him. :)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
dan....@usask.ca
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
To attract good fortune, spend a new penny on an old friend, share an old
pleasure with a new friend and lift up the heart of a true friend by
writing her name on the wings of a dragon.
-Chinese proverb
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Christopher Michael Jones
Doug Craigen (d...@cyberspc.mb.ca) wrote:
: Eric Kniffin wrote:
: >
: > jw wrote:
: > >
: > > In <01bbc62c$da817b00$7ec4abcf@default> "Kevin Thomas"
: > > <foo...@slip.net> writes:
: > > >
: > > >The "grandfather paradoxes" are actaully just erros of logic. There
: The "grandfather paradoxes" are for wimps. Anybody with guts would go back
: and kill themself. The grandfather parodox has me terrified to encourage my
: kids to follow my footsteps in physics. If I start up a dynasty of
: physicists, I increase the odds of being bumped off as a part of somebody's
: thesis research.
: My favorite of these is to arrange a completely mechanical situation, such as
: a pair of worm holes such that a ball goes into one, enters the second at the
: end, and comes out the other at the right time to knock itself out of going
: into the first one. No spilled guts, but a paradox nevertheless.
Not really. The paradox is a fault of logic not a fault of physics (or
an indication that time travel is impossible). If your going to violate
causality, you can not do it willy nilly, you must do it "whole hog".
Thus, one is left with the question of where the time traveling ball (or
you or research student) was when the original ball was being hit. You
didn't mention it, but if it travelled back in time, it should have been
there at that time _always_. The problem with all these "paradoxes" is
that they try to create a so-called "hard encounter". However, when a
particluar situation is worked over correctly with careful attention to
logic, the "hard encounter" doesn't happen. At most, the pool balls can
strike a glancing blow, but they do not create a paradox, ever. Besides,
there is also the possiblity that none of this matters anyway. If the
universe is really a "multiple minds / multiple reality" universe, then
all these things can happen (including the hard encounter / "paradox")
without a paradox acutally occuring. Why? Because when you send
something back into the past, it merely creates new branches on the tree
of quantum realities. Cool huh?
lb...@aol.com
Im Artikel <5604cc$o...@pith.uoregon.edu>, cjo...@gladstone.uoregon.edu
(Christopher Michael Jones) schreibt:
>: > > >The "grandfather paradoxes" are actaully just erros of logic.
There
>
>: The "grandfather paradoxes" are for wimps. Anybody with guts would go
back
>
The only reasonable take on the "grandfather paradox" IMO has been written
by someone, whose name is lost to me right now. The story was about
someone exploiting the desert for oil IIRC and there meeting this strange
guy telling him about a time machine. Now the interesting thing was, that
he explained time to be a spiral or helix with one circle having the
dimension of 60 million years. And with his machine he could only jump
from leap to leap, thus 60 Myears to or fro. With the additional notion,
that any chaotic system (this was written at least 30 years back, so
before all the hype about chaos) will converge (like the net is finding a
way for it's mails to arrive where they should, no matter what happens in
between), which would cancel out any grandfather problems. Anyone
remembering the story? Ah, there was a 60 million year old sneaker
footprint being found at the end of the story in a layer of slate()....
The most dangerous untruths are truths slightly deformed.
Lichtenberg, Sudelbuecher
__________________________________
Lorenz Borsche
Per the FCA: this eMail adress is not to
be added to any commercial mailing list.
Uncalled for eMail maybe treated as public.
Eric Kniffin
Christopher Michael Jones wrote:
> Besides,
> there is also the possiblity that none of this matters anyway.
That's for sure.
> If the
> universe is really a "multiple minds / multiple reality" universe, then
> all these things can happen (including the hard encounter / "paradox")
> without a paradox acutally occuring.
Well, I was thinking of possibility: that time travel only exists in comic
books and movies.
I can't remember if I posted this or emailed it to someone. But I'd like to
know why anyone thinks that time travel is possible. I know that Einstein
theorized that if we travel REALLY fast, it will seem like we were traveling
for a short time, but when we stop we will find that the rest of the world
has experienced a much greater time. I suppose that the faster we travel,
the greater the time difference will be. But how has this theory been
tested? (I've only heard of this theory. I dont know why Einstein thought
this would happen. I just don't know anything about this stuff.)
But what I don't understand is how people decided that, because of that
theory, we must be able to go forward and backward in time. That's quite a
bit different. I mean WAY different. Is there another theory, based on
Einstein's, that explains this? (In which case, it's a theory based on a
theory, not a theory based on fact.) Is the other theory completely
unrelated to Einstein's? Who is the author of this other theory?
I really wish I knew more about this stuff. Are there any "E=mc2 For
Dummies" type of books out there that I can read?
jw
In <327FA3...@warwick.net> Eric Kniffin <lao...@warwick.net>
writes:
>jw wrote:
>> We already know that the
>> past can't be changed - because then the present
>> would be different - the question is *why*?
>
>anything else dealing with this stuff. I'm only going to comment on
the
>observable results of all of this.
>As I see it, there are two possible answers:
>
>1-Time travel is not possible. We don't have any evidence of any
>time-travellers from our future. And I don't believe that it could
ever be
>kept in total secrecy. I imagine that there will always be bad guys
who want
>to come back and rule the world, and we'd know about them.
This explanation (macroscopic time travel is not possible)
covers all known facts - also fits
the relativity theory. I see nothing wrong with
this simple and elegant explanation. Do you?
>2-In answer to "We already know that the past can't be changed -
because then
>the present would be different - the question is *why*?", we DON'T
know this
>at all. There was a science-fiction book called "Thrice Upon A Time",
where
>a guy figured ot how to send information back a few minutes in time to
>himself. Those who received that information acted on it, and changed
>everything from the moment they received the information onward. They
talked
>about what they called the "Superobserver", who existed outside of
>time/space/reality. The superobserver would see things happen. Then
it
>would see the information being sent back in time. Then it would see
the new
>reality forming from the moment that the informatin was received.
But the superobserver's observation time was obviously *not*
our physical time. It is misleading to speak of
both in the same terms... Yes, it *is* possible,
even for us, to *observe* events in a different time sequence:
just videotape them, and then flash back and forth
watching the tape. This could create an *illusion*
of time travel. Similarly, your superobserver is experiencing
an illusion...
>This could be what is happening all the time for us. We think that
Hitler
>was a monster.
Sure. And we are right, are not we? I mean: if we *do* think
that, we can't simultaneously think that we are wrong...
>But maybe something worse happened, people went back in time
>to change it, and Hitler was the result.
But if they went back - and *did* change it - then
it *never happened*; and if it never happened, then
these people had no reason to go back
and change it, and so did not! (Indeed, the *same*
people would not even *live* if the past had been
changed, because conception and chromosome
dance are such sensitive, delicate processes).
The "superobserver", therefore,
observed what *never was*, experienced an
*illusion*, "virtual reality".
There is no problem with that.
This interpretation covers all angles, even in
the science fiction scenario that you described.
>Maybe the "previous" problem was
>so much worse that they didn't bother to go back and do away with
>Hitler.
So, your theory has it that our world is the *best
possible*, and *this* is why no one goes
back in time - though they could - they
just don't want to spoil what's already optimal.
This would still make time travel impossible - but
it would be, according to you, a *moral* impossibility.
Your theory is that no being *physically* capable
of time travel is *morally* capable of it; and so
it never happens.
I find this implausible, first, because
moral constraints are not so rigid; people would differ
in their estimates of what's the best past and
the best present. But more importantly, there
remains the problem of "what if". Suppose a
certain experiment just never happens to be run, I
*still* want the laws of nature to give me the answer to
what would happen if it *was* run. And here we still run
into paradox with time travel: the effect would annihilate
its own cause and therefore itself.
There are, however, two other ways to look at it, which I
rather like, which would both make what
*looks* like time travel possible.
One cannot change one's own past -
because that change would negate itself.
But one can change the past's exact *replica*.
(1) Suppose that all that *can* happen
really *does* - all possibilities are realized.
(Why and how should the universe choose between
them?) However, not all things that are possible
are *compossible*: it was possible for Hitler to
live *or* not to live - but not *both*.
So, for all possibilities to be realized,
the universe has to split, every split moment, into
many parallel universes, each of which realizes
one set of compossible events.
Then there would be no *logical* problem with "traveling" into
the *present* of a parallel universe - which is just *like*
our past - and changing it.
(2) The other possibility does not require
parallel universes. Suppose we could *re-create*
the past - make an exact replica of it, resurrect
all the people that lived then, put them in
exactly the same situations etc.
There is nothing logically impossible
in this, and nothing that violates causality.
But then one could change this resurrected "past",
and replay the events differently.
In both (1) and (2), the "time travelers" are also
"superobservers" - they observe *both* time
sequences, the original and the revised.
Both sequences are *real* - yet the time travel is illusory.
jw
In <327F7F...@cyberspc.mb.ca> Doug Craigen <d...@cyberspc.mb.ca>
writes:
>Eric Kniffin wrote:
>>
>> jw wrote:
>> >
>> > In <01bbc62c$da817b00$7ec4abcf@default> "Kevin Thomas"
>> > <foo...@slip.net> writes:
>> > >
There
>
>The "grandfather paradoxes" are for wimps. Anybody with guts would go
back
encourage my
>kids to follow my footsteps in physics. If I start up a dynasty of
>physicists, I increase the odds of being bumped off as a part of
somebody's
>thesis research.
On the other hand, maybe your *conception* was a result
of just such a project: so don't keep your kids away from
physics, or you may go out like
a candle, never to have existed. :-)
>My favorite of these is to arrange a completely mechanical situation,
such as
>a pair of worm holes such that a ball goes into one, enters the second
at the
>end, and comes out the other at the right time to knock itself out of
going
>into the first one. No spilled guts, but a paradox nevertheless.
Kip Thorne describes exactly this model.
One case was for the billiard ball to give itself, in the past,
a glancing blow on the right, to change its trajectory
so that next "time" - back into the past again -
it gave itself a glancing blow on the *left* - and so on.
The result is that a macroscopic, classical body
would behave in an indeterministic fashion, having
two or many futures.
But then Hawking figured out that a beam
of vacuum oscilations would arise, apparently always
destroying the whole
setup just before it could become a time machine...
||"Hawking suspects that the growing beam of vacuum
||fluctuations is nature's way of enforcing
||chronology protection: *Whenever one tries
||to make a time machine, and no matter what
||kind of device one uses in one's attempt
||(a wormhole, a spinning cylinder, a "cosmic
||string", or whatever), just before one's
||device becomes a time machine, a beam of
||vacuum fluctuations will circulate through
||the device and destroy it.*
||[...] My own calculations [...]
|| suggest to me that Hawking is
||likely to be right. However, we cannot know
||for sure until physicists have fathomed in depth
||the laws of quantum gravity."
(Kip Thorne, _Black Holes & Time Warps_, Chapter 14)
Michael L Roginsky
Pardon my comment, colleagues: Light travels at a precise speed, 186000
miles/sec or so. At that speed relative time=0. This is a paradox that
Einstein treated as a fact. As you well know travel is both a particle
and a wave. Not until we transcend to another set of dimensions, one of
which is time itself, light will be a paradox. How about "black holes"
and pulsars? Gtes to another universe we cannot detect because our
senses are incapable to do so? Cheers........:) Micro.
In <553u2i$l...@atlas.vcu.edu> phy...@atlas.vcu.edu (David L. Smith
Jr.) writes:
>
>abos...@netcom.com (Alan Bostick) writes:
>
>>gre...@ptdcs2.intel.com (Jeff Greason) writes:
>
>
>>>In article <53sv1h$c...@news.xs4all.nl>, mar...@xs2.xs4all.nl (Marco
"Mark-1"
>>>Nelissen) writes:
>
>>>Your premise is flawed. Yes, there are some "tricks" or "loopholes"
in
>>>presently understood physics which would appear to permit "apparent"
FTL
>>>travel. Most of them are understood to be mathematical artifacts of
>>>non-physical conditions, but a few of them (tunneling & Thorne-type
>>>wormholes, for example), may be physically attainable by a suitably
advanced
>>>technology.
>
>>>However, to the best of our current understanding, *all* of these
tricks
>>>violate causality as it is presently understood. That doesn't mean
they're
>>>impossible -- but it means that either our understanding of the
physics
>>>is wrong, or our definition of causality needs improvement. If you
want an
>>>opinion, my opinion is that our understanding of causlity is
imperfect, but
>>>the universe doesn't respect my opinion :-)
>
>>Kip Thorne's wormhole-based time travel devices do not seem to
violate
>>causality; at least it does not generate grandfather (Kip calls it
"matricide")
>>paradoxes. He discusses the issue in his popular book, BLACK HOLES
AND TIME
>>WARPS: EINSTEIN'S OUTRAGEOUS LEGACY.
>
>These types of time machines do violate the father paradoxes.
>If one worm hole end is brought to a relativistic speed and dialated
>in time, anyone from the forward time part of the hole could travle
>back in to cause such a paradox, remember the dilation is only a local
>effect for that end of the worm hole.
>
>
>>He *does* warn, however, that a wormhole-based time machine would
very likely
>>blow itself up in a fountain of amplified vacuum energy.
>
>>--
>>Alan Bostick | "Dole is so unpopular, he couldn't sell
beer on
>>mailto:abos...@netcom.com | a troop ship." (Ohio Republican Senator
William
>>news:alt.grelb | Saxbe on Bob Dole's early career in the
Senate)
>>http://www.alumni.caltech.edu/~abostick
>>http://www.theangle.com/ The first site with a brain. Yours.
Cris Jacobin
In article <328433...@mbox2.singnet.com.sg>, "Doug \"thE_bUG\" Tham"
<ray...@mbox2.singnet.com.sg> wrote:
> lb...@aol.com wrote:
>
> ---[GIGANTIC snip! sorry!]---
>
> > Ah, there was a 60 million year old sneaker
> > footprint being found at the end of the story in a layer of slate()....
>
> Interesting story...sorry about intruding here, but there are tons of
> REAL fossil anomalies, e.g. imprint of what looks like a sandaled
> footprint crushing a trilobite; toads, frogs, spark plugs, nails and
> even a pterosaur found trapped in unbroken coal...looks like the guy who
> made that time machine was pretty careless, huh?? :)
I've heard stories of frogs, trapped within coal, seemingly hibernating since
they spring back to life. How they knew there was a frog in a particular rock
of coal, I don't know. Maybe they went around x-raying chunks. ;)
Of course, the shows/articles on stories of this ilk, tend to be spouted
mostly from WeeklyWorldNews genre of periodical. Heh, "Sightings", in print.
Since you quote that there are 'tons' of REAL fossil anomalies, can you
be so kind as to give me a URL or two, or other sources for further information?
-Jac 'Thanks in advance'
mbcx...@stud.man.ac.uk
If time travel was possible and you could go into the past and alter it,
i.e. I went back and shot my grandad, Then I would no longer exist to
kill my grandad, but if I did exist then I did kill my grandad. So both
things have happend ( there would be an infinate interchange between my
existance and nonexistance ) so a paradox wopuld be set up and the time
relative to the universe would stop. So it would be possible to alter
history but at a great expense to where the alteration occurd.
Mike Abernathy
wa...@cs.toronto.edu (Wayne Hayes) wrote:
>In article <327FA3...@warwick.net>,
>Eric Kniffin <lao...@warwick.net> wrote:
>>2-In answer to "We already know that the past can't be changed - because then
>>the present would be different - the question is *why*?", we DON'T know this
>>at all. There was a science-fiction book called "Thrice Upon A Time", where
>>a guy figured ot how to send information back a few minutes in time to
>>himself. Those who received that information acted on it, and changed
>>everything from the moment they received the information onward. They talked
>>about what they called the "Superobserver", who existed outside of
>>time/space/reality. The superobserver would see things happen. Then it
>>would see the information being sent back in time. Then it would see the new
>>reality forming from the moment that the informatin was received.
>But this reduces to the same paradox. If, say, the guy gets mugged and
>then sends himself a message back in time saying "don't turn left into
>that dark alley down the street 2 minutes from now", and then gets the
>message, and doesn't turn down the alley, then... who sent it? Certainly
>not the same guy who DIDN'T turn into the alley, because he never turned
>into the alley, and so didn't get mugged, and so didn't send the message.
>Well, then, who DID send the message? And what happened to the entire
>universe belonging to the guy who DID send the message? Did it cease
>to exist? When did it cease to exist? The moment he sent the message,
>or the moment (5 minutes previous) that the message is recieved.
>Time travel may not be impossible, but if it does occur, it's almost
>certainly not possible to change *anything* in the past --- at least not
>in the same universe that you're doing the travelling in.
As far as branching into another universe, that's an old SF idea. A
good recent take-off of this was Hogan's The Proteus Operation. If
you want to allow time travel in without branching and still avoid
paradoxes, and want to carry this to it's bitter end, there was an old
SF story about a guy who went back in time and discovered raindrops
like bullets (not being able to change the past, his body couldn't
change their original path), sandwiches that couldn't be bitten, etc.
You can go even further, because the body of our theoretical
time-traveler wouldn't even displace air, so he'd die horribly right
after arrival. Maybe he'd even explode. Maybe there'd even be some
sort of nuclear explosion, if the atoms of his body (and time
machine?) tried to occupy the same space as air / soil / trees, etc?
Hmmm, remember the Tunguska blast in Siberia back early this century?
Could it be? Nah!
Mike Abernathy
"Doug \"thE_bUG\" Tham" <ray...@mbox2.singnet.com.sg> wrote:
>lb...@aol.com wrote:
>---[GIGANTIC snip! sorry!]---
>> Ah, there was a 60 million year old sneaker
>> footprint being found at the end of the story in a layer of slate()....
>Interesting story...sorry about intruding here, but there are tons of
>REAL fossil anomalies, e.g. imprint of what looks like a sandaled
>footprint crushing a trilobite; toads, frogs, spark plugs, nails and
>even a pterosaur found trapped in unbroken coal...looks like the guy who
>made that time machine was pretty careless, huh?? :)
Say what? Have you got any sources for this? I'd be fascinated.
Wayne Throop
: jbur...@crl.com (Jason Burrell)
: I was told by a high school physics instructor (a very bright man,
: incidentally) that, quote, "They tested this. They took two clocks,
: one on the ground, and put the other in a 747 and flew it around the
: world a couple of times. After 6 or 8 times around, there was a
: microsecond difference or so in the clocks." He might have been making
: up that anecdote to get the point across, though.
Note [1], below. There has been a recent criticism of the statistical
analysis of this experiment, claiming that the statistical analysis
by which the error limits were calculated are invalid, but most don't
take this criticism seriously. Further, the GPS satellites are going
fast enough, and need enough accuracy, that their clocks need to be
rate-adjusted to account for time dilation (both gravitational and
traditional velocity time dilation). See the book "Was Einstein Right"
by Clifford Will for other (mostly general relativity and gravity)
cases where relativity has been confirmed.
:: But what I don't understand is how people decided that, because of
:: that theory, we must be able to go forward and backward in time.
: I believe people are assuming that since the time dilation follows a
: particular curve, and since Einstein theorized that time "stops" when
: you're at c, the natural progression is for time to regress when one
: is travelling in excess of c. [...]
: Folks correct me if I'm wrong here.
"You're wrong here."
The time experienced by an object traveling nearer and nearer lightspeed
does indeed approach zero as a limit, but above lightspeed, it becomes
imaginary, not negative. Thus, the usual "FTL implies time travel" meme
is NOT due to extrapolating time dilation to FTL speeds. It is,
instead, based on a *different* relativistic effect that most popular
treatments don't mention, what Feynman called "failure of simultaneity
at a distance" in his "Lectures on Physics".
See also Hinson's FTL page and my own less detailed essay explaining this.
http://www.physics.purdue.edu/~hinson/ftl/FTL_intro.html
http://sheol.org/throopw/tachyon-pistols.html
--
Wayne Throop thr...@sheol.org http://sheol.org/throopw
thr...@cisco.com
--
[1] Hafele&Keating, Around-the-World Atomic Clocks Science, 1972 v177, p166-170
Around-the-World Atomic Clocks: Predicted Relativistic Time Gains
During October 1971, four cesium beam atomic clocks were flows on
regularly scheduled commercial jet flights around the world twice,
once eastward and once westward, to test Einstein's theory of
relativity with macroscopic clocks. From the actual flight paths of
each trip, the theory predicts that the flying clocks, compared
with reference clocks at the U.S. Naval observatory, should have
lost 40+-23 nanoseconds during the eastward trip, and should have
gained 275+-21 nanoseconds during the westward trip. The observed
time differences are presented in the report that follows this one.
Around-the-World Atomic Clocks: Observed Relativistic Time Gains
Four cesium beam clocks flows around the world on commercial jet
flights during October 1971, once eastward and once westward,
recorded directionally dependent time differences which are in good
agreement with predictions of conventional relativity th eory.
Relative to the atomic time scale of the U.S. Naval Observatory,
the flying clocks lost 59+-10 nanoseconds during the eatward trip
and gained 273+-7 nanoseconds during the westward trip, where the
errors are the corresponding standard deviations. These results
provide an unambiguous emperical resolution of the famous clock
"paradox" with macroscopic clocks.
Jim Batka
First of all, I've *heavily* editted the followup for this (I'm sure
that many of the newsgroups originally in the header couldn't care
less about this topic).
Doug "thE_bUG" Tham wrote:
> lb...@aol.com wrote:
<snip>
> > Ah, there was a 60 million year old sneaker
> > footprint being found at the end of the story in a layer of slate()....
> Interesting story...sorry about intruding here, but there are tons of
> REAL fossil anomalies, e.g. imprint of what looks like a sandaled
> footprint crushing a trilobite; toads, frogs, spark plugs, nails and
> even a pterosaur found trapped in unbroken coal...looks like the guy who
> made that time machine was pretty careless, huh?? :)
Good grief! Don't let the creationist "nu-nus" hear this or it'll
drive this newsgroups s/n -> 0 (if you are a creationist & not a
"nu-nu" then that remark was not direct @ you).
If anyone is aware of information regarding these "geologic anomalies"
on the net, could you please post information on how to review it?
Thanks,
--
Jim Batka Email: jim....@sdrc.com
Contrary to popular opinion, the word "gullible" is not in
(American) Dictionaries.
Jim Batka
David L Evens wrote:
>
> Marcel (mar...@javanet.com) wrote:
> [Much snippage.]
>
> : Experiments have been done in electromagnetics. One experiment that comes to mind is the
> : famous "Philadelphia" Experiment. I know, it's been covered up by the government for a
> : long time, but the data gathered from this could be quite useful in furthering research
> : in the "possibility" of c+ travel. If a way to "drop out", if you will, of this
> : "universe" were possible, then would not we be able to attain c+ travel? The other
> : possibility would be that we would not be travelling faster than light, but, rather,
> : utilize space curvature to get to where we want to go. In essence, "hyper-space".
<More creative elimination>
I read an interesting bit of fiction regarding "hyper-space"...
For some reason humans desperately needed some form of FTL. A scientist
mathmatically proved the existance of and a method of getting into
"hyper-space". He kept trying to get the government to notice and fund
his project and he kept getting passed over in favor of "goof-ball"
theories.
He finally storms into the office of the scientist in charge of
allocating
research money and demanded an explanation.
The Chief scientist replied that they had discovere "hyper-space" a long
time ago and that light move *slower* in "hyper-space" than it did in
"normal space".
Just something to keep those mental wheels turning :).