Recommended Book:"Shifting Worlds Changing Minds"
Steve Reiser
I'm currently reading the book "Shifting Worlds, Changing Minds" by
Jeremy W. Hayward published by New Science Library An Imprint of
Shambala Publications, Inc. Horticultural Hall, 300 Massechusetts
Avenue, Boston, Massechussetts 02115 dated 1987.
Quote:
New Science Library presents traditional topics from a modern
perspectice, particularly those associated with the hard sciences -
physics, biology, and medicine - and those of the human sciences -
psychology, sociolgy, and philosophy.
The aim of this series is the enrichment of both the scientific and
spiritual view of the world through their mutual dialogue and exchange.
End quote.
This book discusses man's perception of reality through science and
humanities and how objective any thoughts really are, whether ego exists
or not, duality, versus unity, objects, processes, an in-depth
evaluation of how the mind processes input from our senses, the need to
study subjective experience, and much more.
He indicates that a revolution in thinking more important than
relativity or quantum theory is occurring.
This book demands a whole new perspective on science, religion,
psychology, etc.
I feel that if a large number of people on this network were to read
this book it could drastically alter the content and perspective of all
discussions between the religious and scientific communities represented
here. Dogmatic people from either side of the issue will not like what
they read here, however for me it is altering and unifying my view of
the universe from perspectives I had never even dreamed of.
Steve
--
Steve Reiser (rei...@pmafire.UUCP or ...!uunet!pmafire!reiser)
Eric Marsh
I have been reading a book on quantem reality over the Yule holiday, and
came up with a simple question that I'm sure someone here can answer.
My question is this:
If an object is approaching me from one direction at .9c, and another
object is approaching me from the opposite direction at .9c, it would
seem to me that relative to the first object, the second object would
be moving at 1.8c. Since nothing can move faster than c, this is thus
impossible, yes? But if that is the case, then it would follow that from
my initial position neither of those two objects could be approaching
me at a greater combined speed than c. This does not appear to work.
What gives?
Thanks,
Eric
Greg Kuperberg
>If an object is approaching me from one direction at .9c, and another
>object is approaching me from the opposite direction at .9c, it would
>seem to me that relative to the first object, the second object would
>be moving at 1.8c.
Tangents of angles do not add the normal way, they add by the sum-angle
rule:
tan(a+b) = (tan(a)+tan(b))/(1-tan(a)*tan(b))
It's also true that velocities in special relativity do not add the
normal way, they add by the velocity addition rule:
vtotal = (v1+v2)/(1+v1*v2)
in units in which c=1. Note that if v1<c and v2<c, then vtotal<c also.
The similarity between these two formulas is not an accident. Indeed,
it is natural to associate to a velocity v another number r, called the
rapidity, such that v = tanh(r), where "tanh" is the hyperbolic tangent.
Rapidities add in the usual way.
Why do we need a velocity addition rule? Special relativity predicts
time dilation and Lorentz contraction for moving objects, and both of
these effects modify velocities of objects. Perhaps the most important
effect that must be considered is the fact that if two events occur at
the same time but in different places for a stationary observer, then
in general they occur at different times for a moving observer.
Putting all of these effects together, the bottom line is the above
formula.
----
Greg Kuperberg
gr...@math.berkeley.edu
Bull Engineers
v = v1 + v2 (1)
is merely an approximation. The actual formula is
v = (v1 + v2) / (1 + (v1 * v2) / c ** 2)) (2)
Note that for velocities v1 << c and v2 << c, (2) is very close to (1).
Note also that if either v1 or v2 is equal to c, everything else
cancels, and the result is v = c, as required by the Special Theory.
Mcirvin
>object is approaching me from the opposite direction at .9c, it would
>seem to me that relative to the first object, the second object would
>be moving at 1.8c. Since nothing can move faster than c, this is thus
>impossible, yes? But if that is the case, then it would follow that from
>Thanks,
> Eric
Actually, relative to the first object, the second object is moving at LESS
than c, even in this situation. Just adding the velocities to go from one
reference frame to another is called a Galilean transformation, and it applies
with a high degree of accuracy for small velocities, but for velocities
near c you must use something called a Lorentz transformation instead; then, if
object 1 is approaching you at velocity v1 and object 2 is approaching at
velocity v2, in opposite directions, v2 relative to v1 is moving at
(v1 + v2) / (1 + v1*v2/c^2).
(Beiser, CONCEPTS OF MODERN PHYSICS, New York: McGraw Hill, 1987, p. 39)
In the specific situation you describe the relative velocity is 0.994475c.
Weird, isn't it? It's not quantum mechanics, just special relativity.
Matt McIrvin
n
Steven Daryl McCullough
>
> Things can move faster than c. Just cause Albert E. speculated that they
> can't don't make it so. Albert was spot on about alot of the mechanics
> of our old universe and completely wrong about others. His notion of c
> being unexceedable was his biggest goof and he died trying to make his final
> equasions work because of it.
I have two points. The first is that this discussion should be changed
to sci.physics, since it has nothing to do with psychology. The second
is that, Daniel, I think you are almost completely wrong. Einstein's
special theory of relativity has passed every test with flying colors,
and I would consider it his greatest success, rather than his biggest
goof.
What Einstein was working on in the last years of his life was a
Unified Field theory combining gravity and the electromagnetic force.
The reason he was stumped had nothing to do with whether the speed of
light can be exceeded.
Daryl McCullough
Hunting the Snark
In article <52...@husc6.harvard.edu>, mci...@husc9.harvard.edu (Mcirvin) writes...
I read the question a little differently. A is approaching ME at .9c,
B is approaching ME from the opposite direction at .9c. So relative to ME,
A is approaching B at 1.8c. That is, if I measure A to be .9 light minutes away
and B to be .9 light minutes away, then 1 minute from now, A and B will meet;
a seperation of 1.8 light minutes will have been traversed in 1 minute. Is this
wrong?
I thought only when it is A trying to measure B's speed or vice-versa that one
must use
v = (v1 + v2) / (1 + v1*v2/c^2).
Steven Marshall
"Hard to say Ma'am. I think my cerebellum just fused" -- Calvin
Richard M. Mathews
>I always thought that what Einstein said was that nothing with mass could
>ever travel *at* the speed of light, and not that nothing could travel
>*faster* than c (tachyons).
This was recently covered in sci.physics. Einstein did say nothing could
go faster than light and only massless particles can go at the speed of
light. I presented a simple proof that if Special Relativity is correct
and if information can be transmitted faster than light as seen by any
observer, then causality can be violated (you can get a response before
you send the inquiry). If tachyons exist and can interact with regular
matter, then either Special Relativity or causality have problems.
> Don't the Lorentz transformations give strictly imaginary values for
>apparent length, mass, etc. for tachyons, though, due to sqrt(1 - v^2 / c^2)?
>How could we ever observe such objects!?
Actually, my proof did not require any particles to move faster than light.
It only assumes that information makes it a certain distance in a certain
time such that distance/time > c. This avoids all imaginary numbers. You
still end up with causality violation.
References:
A.P.Lightman, W.H.Press, R.H.Price, and S.A.Teukolsky,
_Problem_Book_in_Relativity_and_Gravitation_ (Princeton,
1975), pp. 5-6,135-136,358
Richard M. Mathews D efend
ric...@locus.com E stonian-Latvian-Lithuanian
lcc!ric...@seas.ucla.edu I ndependence
...!{uunet|ucla-se|turnkey}!lcc!richard
Mcirvin
>
>
>I read the question a little differently. A is approaching ME at .9c,
>B is approaching ME from the opposite direction at .9c. So relative to ME,
>A is approaching B at 1.8c. That is, if I measure A to be .9 light minutes away
>and B to be .9 light minutes away, then 1 minute from now, A and B will meet;
>a seperation of 1.8 light minutes will have been traversed in 1 minute. Is this
>wrong?
>
>"Hard to say Ma'am. I think my cerebellum just fused" -- Calvin
OK, if that's what the question meant, there's nothing in relativity that
forbids that happening. The statement in special relativity (I will ignore
general relativity, Hubble flow, etc.) that says c is a limit for relative
speeds simply means that an observer in one reference frame will never
encounter an object moving relative to him/her with a speed greater than
c. The observer will in fact measure the separation between the two objects
closing at faster than c, but an observer standing on either of the two
objects A or B will measure the relative speed as less than c. That is
what is meant by relative velocity in special relativity.
Another way of saying this is to imagine that all observers in inertial
reference frames are naive and only measure what they think to be absolute
velocities, assuming that they are standing still. SR says that nobody will
measure a velocity greater than c under such a program of observation.
Again, I am deliberately ignoring GR effects such as the expansion of the
universe.
Thanks for forcing me to clarify my statements....
Matt McIrvin
s
ben a green
We shouldn't pound this question into the ground, but consider the
fact that we don't need all these observers, even "ME", to state the
facts. Just say, there are two objects A and B located with respect to
frame F at -.9 light-minute and +.9 light-minute. The velocity of A
with respect to F is .9c; that of B is -.9c. They meet in 1 minute.
No problem. Nobody has speed greater than c.
If you ask about the speed of A relative to B, then you are changing frames,
and you need the Lorentz transformation to do that. And you can derive the
formula for composition of velocities, etc. Still nobody exceeds speed c.
When we drag in observers and require them to be naive, etc., it looks to
beginners as if physics is subjective, and it isn't.
Ben
--
Ben A. Green, Jr.
gre...@crd.ge.com
Speaking only for myself, of course.
ted.horoschak
Given that the frame F is in empty space, how would you know that it is an
inertial frame?
Ted Horoschak
ben a green
In article <GREENBA.91...@gambia.crd.ge.com>, gre...@gambia.crd.ge.com (ben a green) writes:
> We shouldn't pound this question into the ground, but consider the
> fact that we don't need all these observers, even "ME", to state the
> facts. Just say, there are two objects A and B located with respect to
> frame F at -.9 light-minute and +.9 light-minute. The velocity of A
> with respect to F is .9c; that of B is -.9c. They meet in 1 minute.
> No problem. Nobody has speed greater than c.
Given that the frame F is in empty space, how would you know that it is an
inertial frame?
Didn't say "empty space" -- just no observers.
Dave_Waller
>
> Given that the frame F is in empty space, how would you know that it is an
> inertial frame?
By taking that superball out of your spacesuit pocket and releasing it
from your hand. If it doesn't fly away, then you're in an inertial
frame.
>
> Ted Horoschak
> ----------
Dave Waller \ The opinions expressed are solely my own, and in no way
Hewlett-Packard Co. \ represent those of my employer (but we all know
da...@hpdstma.ptp.hp.com | hplabs!hpdstma!dave \ they should!)
Ray Cromwell
>heks...@Apple.COM (Ben Hekster) writes:
>>I always thought that what Einstein said was that nothing with mass could
>>ever travel *at* the speed of light, and not that nothing could travel
>>*faster* than c (tachyons).
>
>This was recently covered in sci.physics. Einstein did say nothing could
>go faster than light and only massless particles can go at the speed of
>light. I presented a simple proof that if Special Relativity is correct
>and if information can be transmitted faster than light as seen by any
>observer, then causality can be violated (you can get a response before
>you send the inquiry). If tachyons exist and can interact with regular
>matter, then either Special Relativity or causality have problems.
Why is causuality used to prove FTL is false. What is wrong with violating
causuality? Because it violates common sense? Relativity and Quantum
Mechanics already have done that.
And doesn't the uncertainty principle provide a loophole? For instance,
what would happen if an object came within 1 planck length/second of the
speed of light. ( c-plancklenght/s) Couldn't this object perhaps
'tunnel' past the speed of light barrier (which requires infinite
energy)? Does Causuality violation violate thermodynamics? (entrophy could
go in reverse?) The way I see it, physics breaks down at greater
than light speeds. We really don't know what happens? Perhaps time flows
backs, and you are in a mirror universe where the slowest speed is light,
mass is negative, and gravity is of the opposite curvature? Who knows?
I'm not a physicist, I'm just speculating. But why is causuality used
as proof that FTL does not exist?
Mcirvin
>I'm not a physicist, I'm just speculating. But why is causuality used
>as proof that FTL does not exist?
Not proof, just a good reason to believe it doesn't exist. Causality violation
would indeed violate common sense, but more importantly, it would require a
lot of reinventing to make up a physical theory that would include it, and
since nothing has yet been seen that violates causality, it would at present
be unmotivated. All that would change if causality violation emerged from
an experimental result: physicists would scramble to invent theories that
violated causality, and faster-than-light travel might seem like a viable
possibility.
Matt McIrvin