Re: Ultimate Weapon (plot hole)
IsaacKuo
Note--I'm crossposting this article from alt.battlestar-galactica
into rec.arts.sf.science...
This discussion is about using a SFnal "jump" drive as a weapon
by instantly teleporting one solid object into a target solid object.
What would be the result?
Tim McGaughy wrote:
>OrionCA wrote:
>>The inside of an atom is fairly close to empty space. It's even more
>>"vacant", proportionately, than the space between the planets in our
>>solar system. When they fire an atom smasher they don't call it
>>"neutron bombardment" for nothing - it takes literally billions of
>>high energy neutrons slamming into a nuclei to produce an alpha
>>particle.
>>If you materialized in the middle of a sofa chances are all they'd get
>>would be a miniscule rise in room temperature and a real conversation
>>piece of a couch. Oh, yeah: you'd die. But not of a thermonuclear
>>explosion; just terminally clogged arteries.
This depends on how "hollow" the sofa is. Unless the sofa
is an inflatable, I'd expect a serious explosion. Most
of a human body is nearly incompressable water. It's
not COMPLETELY incompressible, of course. But instantly
intermeshing the water atoms with the sofa's atoms implies a
significant increase in density.
How much potential energy does this density increase
represent? Well, roughly, it's equal to the change in
volume multiplied by the pressure. Because water is
nearly incompressible, the pressure is enormous. So
there's going to be a lot of energy, and this will be
rapidly released in an explosion. My gut feeling is
that the specific energy will be far greater than any
chemical fuel, but I don't know how it would compare
to a nuclear warhead.
>Nope. At the very least, chemical bonds would be disrupted. For
>starters. You WILL have billions of nuclear particles slamdancing
>around, and neutrons are very likely to collide with other subatomic
>particles at some point.
There aren't a bunch of neutrons just bouncing around
beforehand, so there won't be any neutrons at the start.
Therefore, nuclear fission isn't going to happen at the
very start. Also, nuclear fission isn't going to give
you a runaway chain reaction anyway because there simply
aren't any atoms around looking to pop out extra neutrons.
However, there is going to be some nuclear fusion at the
very start. A nucleus is on the order of 0.01% the
diameter of its atom. That implies the nucleus is on
the order of 10^(-12) the volume of its atom. Thus,
where solid materials overlap, each nucleus has on
the order of a one in million million chance of
engaging in fusion. That doesn't sound like a lot,
but there are on the order of 10^28 atoms in a human
body. So maybe some fusion will occur at the start.
It doesn't sound like much energy to me, but I really
don't know.
Assuming the initial fusion doesn't provide all that
much energy, we still have a mass of very unhappily
supercompressed solid material. I'm pretty sure that
water supercompressed into twice its normal liquid
density will be a dense plasma. THAT might conceivably
be fertile grounds for a thermalnuclear fusion bomb
reaction. My gut feeling is that it's still not
enough density/pressure/temperature to really be good
enough for fusion, and that there's not enough of
easily fusable nuclei around anyway...
...My guess is that all nuclear reaction effects
combined will not be significant, but the electromagnetic
effects of atoms being unhappily supercompressed will
still result in a big explosion--bigger than that of
a chemical explosive warhead.
Isaac Kuo
rap...@netscape.net
IsaacKuo wrote:
> This depends on how "hollow" the sofa is. Unless the sofa
> is an inflatable, I'd expect a serious explosion. Most
> of a human body is nearly incompressable water. It's
> not COMPLETELY incompressible, of course. But instantly
> intermeshing the water atoms with the sofa's atoms implies a
> significant increase in density.
It depends on what the sofa is made of. Most sofas are soft, so they
are compressibile.
>
> How much potential energy does this density increase
> represent? Well, roughly, it's equal to the change in
> volume multiplied by the pressure. Because water is
> nearly incompressible, the pressure is enormous. So
> there's going to be a lot of energy, and this will be
> rapidly released in an explosion. My gut feeling is
> that the specific energy will be far greater than any
> chemical fuel, but I don't know how it would compare
> to a nuclear warhead.
Water at 0.9 times its normal density exerts a pressure of 3000A. This
is 300MPa. Assuming that the water is transported into another body of
water and the pressure is constant at 300MPa, the energy released per
m3 transported is:
E = P*dV = P (as dV = 1)
This gives 300MJ
1m3 of water would be 1000kg, so the above gives
300kJ/kg of water.
TNT is 3MJ/kg. This means that water would be 10 times less explosive.
However, the assumption that water pressure will not increase below 0.9
normal density is probably wrong. Decreasing volume from 0.9 normal
volume to 0.5 volume might increase it by a factor of 5, so rise it to
TNT range.
Erik Max Francis
> This depends on how "hollow" the sofa is. Unless the sofa
> is an inflatable, I'd expect a serious explosion. Most
> of a human body is nearly incompressable water. It's
> not COMPLETELY incompressible, of course. But instantly
> intermeshing the water atoms with the sofa's atoms implies a
> significant increase in density.
>
> How much potential energy does this density increase
> represent? Well, roughly, it's equal to the change in
> volume multiplied by the pressure. Because water is
> nearly incompressible, the pressure is enormous. So
> there's going to be a lot of energy, and this will be
> rapidly released in an explosion. My gut feeling is
> that the specific energy will be far greater than any
> chemical fuel, but I don't know how it would compare
> to a nuclear warhead.
As has been mentioned, even very dense materials are mostly composed of
empty space. Suddenly teleporting one object into another will leave
plenty of room for both atoms to exist without some kind of nuclear
interaction taking place.
As for teleporting a human being into a sofa, sure, water is largely
incompressible, but it's not like humans are buckets of water. The
water in the human body is contained in tissues, and the body as a whole
is under some pressure from our skin, but it's not an enormous amount of
pressure. If you're talking about sofas with cushions, there's some
metal structure, but most of it is low-density fluffy stuff.
Seems to me that if you teleport someone into a sofa, then the subject
dies, obviously, but not much else happens other than the sofa gets a
little bigger and maybe distended in some areas. Yes, they'll be a
pressure increase, but unless it's something under so much pressure that
it's already near failure, I don't see hwo this releases a huge amount
of energy.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
Why can't love be / Like molasses rain
-- Sandra St. Victor
brd...@iusb.edu
> not much else happens other than the sofa gets a
> little bigger and maybe distended in some areas
Hmm, I think there would be more than that. Yes, much of the sofa or
the human body is "empty space"... but if that was all that mattered, I
could compress my arm to a very large degree. The *reason* it's mostly
empty space is the large electrostatic forces - and suddenly doubling
the number of atoms/molecules in a volume is certain to imply a very
different electrostatic field configuration (i.e. - molecular bonds
will be dissrupted). The system will eventually come back to
equilibrium, once a new set of bonds have been formed. As far as the
bulk material goes, this still isn't very great. But for any place
where actual molecules overlap, it would be.
I'm not sure how to BotE this, however - probably based on the
electrostaic field energy density, but this is far from trivial in a
molecue, especially when you don't know what's being superimposed. From
the standpoint of the original "ultimate weapon" aspect, there's just
too many other unknowns. For instance, unless BSG wants to throw out
conservation of energy (like they're following it anyway), you've got
the TANSTAAFL thing - if the end result is a high-energy density, then
you had to put the energy in from somewhere (is this why it takes so
bloody long to "spin up" for an FTL jump? No, I suspect that also moves
at the speed of plot). For that matter, just orbit a star opposite your
opponent, and then "jump" to the other side of the orbit in front of
your enemy. Voila', one very high-speed collision.
Any sufficiently advanced plot twist is truely indistinguishable
from magic. And in case anyone wonders, I really *like* BSG - at least
they make a reasonable attempt at Newtonian motion in free space (my
wife get s a kick out of me cheering anytime a Viper does something
rational, as opposed to acting like an airplane).
--
Brian Davis
Erik Max Francis
> Hmm, I think there would be more than that. Yes, much of the sofa or
> the human body is "empty space"... but if that was all that mattered, I
> could compress my arm to a very large degree. The *reason* it's mostly
> empty space is the large electrostatic forces - and suddenly doubling
> the number of atoms/molecules in a volume is certain to imply a very
> different electrostatic field configuration (i.e. - molecular bonds
> will be dissrupted). The system will eventually come back to
> equilibrium, once a new set of bonds have been formed. As far as the
> bulk material goes, this still isn't very great. But for any place
> where actual molecules overlap, it would be.
I imagine the restructuring will be quick, and wouldn't be pleasant to
watch, but I'm seeing more of a "puff" than anything like you'd consider
an explosion.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
No need to tell her there's a world out there / She knows / She just
doesn't seem worried at all -- Nik Kershaw
IsaacKuo
>>Hmm, I think there would be more than that. Yes, much of the sofa or
>>the human body is "empty space"... but if that was all that mattered, I
>>could compress my arm to a very large degree.
If all the "empty space" were all that mattered, then you wouldn't
be able to sit on a sofa--you'd just fall through it. Obviously, that
doesn't happen.
>>The *reason* it's mostly
>>empty space is the large electrostatic forces - and suddenly doubling
>>the number of atoms/molecules in a volume is certain to imply a very
>>different electrostatic field configuration (i.e. - molecular bonds
>>will be dissrupted). The system will eventually come back to
>>equilibrium, once a new set of bonds have been formed. As far as the
>>bulk material goes, this still isn't very great.
For a gas, this is true. It is in fact very easy to compress a gas.
There's plenty of extra space between the molecules in a gas.
Instantly doubling the number of molecules in a gas will merely
double the pressure.
For a liquid? Liquids are called "incompressable" for a reason.
There isn't all that much spare space in there.
>>But for any place
>>where actual molecules overlap, it would be.
>I imagine the restructuring will be quick, and wouldn't be pleasant to
>watch, but I'm seeing more of a "puff" than anything like you'd consider
>an explosion.
Let's put aside the example of a human teleported into a sofa
as needlessly complex, for now. How about simply teleporting
a sphere of water to overlap another sphere of water? What
would the pressure and energy be like?
I really don't know, but the pressure increase surely can't be
linear (as assumed in the analysis estimating specific energy
similar to TNT). A linear increase in pressure would imply
that merely increasing the pressure to ten times that of the 90%
compression pressure would acheive complete compression.
Obviously, the pressure curve must get steeper before that!
Isaac Kuo
IsaacKuo
rap...@netscape.net wrote:
> Water at 0.9 times its normal density exerts a pressure of 3000A. This
> is 300MPa. Assuming that the water is transported into another body of
> water and the pressure is constant at 300MPa, the energy released per
> m3 transported is:
> E = P*dV = P (as dV = 1)
> This gives 300MJ
> 1m3 of water would be 1000kg, so the above gives
> 300kJ/kg of water.
> TNT is 3MJ/kg. This means that water would be 10 times less explosive.
Thanks! This at least gives us an extremely conservative lower
bound.
> However, the assumption that water pressure will not increase below 0.9
> normal density is probably wrong. Decreasing volume from 0.9 normal
> volume to 0.5 volume might increase it by a factor of 5, so rise it to
> TNT range.
Surely, the pressure increase will be more than linear. If the
pressure-volume curve were linear, then increasing the
pressure 11x would imply negative volume!
Isaac Kuo
Erik Max Francis
> For a gas, this is true. It is in fact very easy to compress a gas.
> There's plenty of extra space between the molecules in a gas.
> Instantly doubling the number of molecules in a gas will merely
> double the pressure.
>
> For a liquid? Liquids are called "incompressable" for a reason.
> There isn't all that much spare space in there.
Sure. The materials rapidly rearrange to relieve the pressure. So now
the sofa increases in volume to the size of a sofa plus a human (very
roughly because lots of parts of the human and the sofa are both very
compressible). This rearrangement wouldn't be pleasant to watch or
experience, but I doubt it would qualify as an explosion in the
vernacular most people expect.
> Let's put aside the example of a human teleported into a sofa
> as needlessly complex, for now. How about simply teleporting
> a sphere of water to overlap another sphere of water? What
> would the pressure and energy be like?
At that point it really depends on what the scenario details. If you
have a tank of water that is under pressure and ten teleport a sphere of
additional water into it, sure, the increase in pressure could certainly
be enough to burst the tank, and that would probably happen pretty
energetically -- the most pressure the tank was initially under, or the
most water was teleported in, the more energetically. Take aerogel and
teleport it into some more aerogel, sure, there's some shifting around
and energy release, but not very much.
It really depends on the specifics. For a human and a sofa, the result
would be mighty gross and wouldn't be fun to watch (and even less fun to
experience), but I don't think you're talking "explosion" level
energetics. You could certainly choose scenarios where it would be
quite energetic, I'm sure.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
Have you ever loved somebody / Who didn't know
-- Zhane
IsaacKuo
Erik Max Francis wrote:
>IsaacKuo wrote:
>>For a gas, this is true. It is in fact very easy to compress a gas.
>>There's plenty of extra space between the molecules in a gas.
>>Instantly doubling the number of molecules in a gas will merely
>>double the pressure.
>>For a liquid? Liquids are called "incompressable" for a reason.
>>There isn't all that much spare space in there.
>Sure. The materials rapidly rearrange to relieve the pressure. So now
>the sofa increases in volume to the size of a sofa plus a human (very
>roughly because lots of parts of the human and the sofa are both very
>compressible). This rearrangement wouldn't be pleasant to watch or
>experience, but I doubt it would qualify as an explosion in the
>vernacular most people expect.
And for the same reason, when you fire a gun, the bullet
gets pushed forward out of the barrel by expanding gases
and then the bullet drops to the ground just outside the muzzle.
No, the expansion of volume is accompanied by a
conversion of potential energy into kinetic energy. This
energy doesn't just magically disappear once the
expansion has stopped.
>>Let's put aside the example of a human teleported into a sofa
>>as needlessly complex, for now. How about simply teleporting
>>a sphere of water to overlap another sphere of water? What
>>would the pressure and energy be like?
>At that point it really depends on what the scenario details. If you
>have a tank of water that is under pressure and ten teleport a sphere of
>additional water into it, sure, the increase in pressure could certainly
>be enough to burst the tank, and that would probably happen pretty
>energetically -- the most pressure the tank was initially under, or the
>most water was teleported in, the more energetically.
Let's assume the water in both cases start off at one
atmosphere, at room temperature. It actually doesn't
matter much what the original pressure is, I think.
What really matters is that suddenly increasing the
density to twice the normal amount is going to massively
increase the water pressure in and of itself.
How much energy is released? Well, if rap...@netscape.net's
conservative calculations are right, it's at least on the order
of TNT. I expect the pressure increase is much greater
than linear, though.
>Take aerogel and
>teleport it into some more aerogel, sure, there's some shifting around
>and energy release, but not very much.
Yes, but I was specifically talking about spheres of water.
With an aerogel, the energy release should be small.
After all, it takes very little work to squeeze a volume of
aerogel into half the original volume.
With water, I expect the situation to be very different.
It's hard to physically squeeze a volume of water
into half the original volume.
Isaac Kuo
rap...@netscape.net
IsaacKuo wrote:
> However, there is going to be some nuclear fusion at the
> very start. A nucleus is on the order of 0.01% the
> diameter of its atom. That implies the nucleus is on
> the order of 10^(-12) the volume of its atom. Thus,
> where solid materials overlap, each nucleus has on
> the order of a one in million million chance of
> engaging in fusion. That doesn't sound like a lot,
> but there are on the order of 10^28 atoms in a human
> body. So maybe some fusion will occur at the start.
> It doesn't sound like much energy to me, but I really
> don't know.
Assuming water, there are 3 possible reactions:
O16 + O16 -> S32 (stable)
H1 + O16 -> F17 (unstable half life of 60 seconds)
H1 + H1 -> He2 (not listed ... so maybe doesn't even form or formation
is endothermic)
IsaacKuo
rap...@netscape.net wrote:
>IsaacKuo wrote:
>>However, there is going to be some nuclear fusion at the
>>very start. A nucleus is on the order of 0.01% the
>>diameter of its atom. That implies the nucleus is on
>>the order of 10^(-12) the volume of its atom. Thus,
>>where solid materials overlap, each nucleus has on
>>the order of a one in million million chance of
>>engaging in fusion. That doesn't sound like a lot,
>Assuming water, there are 3 possible reactions:
>O16 + O16 -> S32 (stable)
>H1 + O16 -> F17 (unstable half life of 60 seconds)
>H1 + H1 -> He2 (not listed ... so maybe doesn't even form or formation
>is endothermic)
Hmm...
He2 can't form. The protons will instantly fly apart
from each other. This isn't fusion; it's not a nuclear
reaction at all. However, it DOES release energy.
The oppositely charged protons will repel each other
with a 1/r^2 electrostatic force. This applies for
near misses as well as direct overlaps. My gut feeling
is that the fraction of "near misses" is still going to
be so low that the energy involved won't be much.
Not compared to the electrostatic forces of the
overlapping atomic electron shells, that is.
Isaac Kuo
David Mitchell
>
> Erik Max Francis wrote:
>>brd...@iusb.edu wrote:
>
>>>Hmm, I think there would be more than that. Yes, much of the sofa or
>>>the human body is "empty space"... but if that was all that mattered, I
>>>could compress my arm to a very large degree.
>
> If all the "empty space" were all that mattered, then you wouldn't
> be able to sit on a sofa--you'd just fall through it. Obviously, that
> doesn't happen.
>
Still seems like quite a handy toy though - presumably you can use it to
create extremely efficient fission weapons (by teleporting two
sub-critical spheres of Pu to the desired detonation point, for example).
It might also be possible to do something similar with fusion: if
instantly doubling the density of your target solid doesn't do it, you
could cascade your teleporters to achieve whatever compression ratio you
want.
ObSF: ORA:CLE
--
=======================================================================
= David --- If you use Microsoft products, you will, inevitably, get
= Mitchell --- viruses, so please don't add me to your address book.
=======================================================================
chorned...@hushmail.com
> >Take aerogel and
> >teleport it into some more aerogel, sure, there's some shifting around
> >and energy release, but not very much.
>
> Yes, but I was specifically talking about spheres of water.
> With an aerogel, the energy release should be small.
> After all, it takes very little work to squeeze a volume of
> aerogel into half the original volume.
>
And yet it is an explosion.
In a volume of air, the molecules are distributed randomly. Therefore,
if you teleport a volume of air into another volume of air, you have
few effects other than suddenly doubling the pressure.
Which creates an explosion. Pressurized aircraft can decompress
forcibly, and gas/vapour explosions or dust explosions can be
destructive. But nothing to compare with an explosion of a comparable
volume of liquid or solid explosive!
> With water, I expect the situation to be very different.
> It's hard to physically squeeze a volume of water
> into half the original volume.
>
> Isaac Kuo
Indeed. Yet it is doable.
For example, I think plutonium can be compressed to half its original
volume by implosion of chemical explosive charge. So, even if no
nuclear explosion happens, a detonation of a nuclear bomb is
destructive.
But now another factor enters. In a solid or liquid compressed to half
its original volume, the atoms are not in random positions, as they are
in gases. Their locations are rather well arranged to avoid each other.
Which does not apply if you teleport matter into matter.
I would say that the chances of a particle winding up in a vicinity of
another decrease as the volume considered - that is, with the cube of
the distance.
The potential energy of an electrical charge in field of another
increases with the inverse of the distance between charges. Thus, there
will be a high-energy tail of nuclei that have been teleported to
near-collision.
But as the size of this tail decreases with cube of distance and energy
increases only with inverse distance, that tail should integrate to a
finite amount of energy, of the same order of magnitude as the
compression component.
Another thing - you are teleporting fermions (mostly electrons, but
also odd mass nuclei) into vicinity of indistinguishable particles.
The minimum momentum of a fermion in the vicinity of its fellow
increases with inverse of the distance - and therefore, the energy
increases with inverse of the SQUARE of the distance, generating a tail
of fast electron which is way bigger than the tail of fast nuclei.
However, since the energy of the tail - square of the distance - still
increases slower than the size of the tail decreases - cube of the
distance - that tail should also integrate to a finite total energy, of
the same order of magnitude as the compression and charge disorder
components. So, in full, there should be an explosion a few times more
powerful than a chemical explosive of comparable volume, accompanied by
a tail of ionizing mild beta radiation - much less powerful than a
nuclear explosion in a similar volume unless a fission chain reaction
is allowed by the critical mass reached.
Wayne Throop
: It really depends on the specifics. For a human and a sofa, the
: result would be mighty gross and wouldn't be fun to watch (and even
: less fun to experience), but I don't think you're talking "explosion"
: level energetics. You could certainly choose scenarios where it would
: be quite energetic, I'm sure.
Well, returning to the simpler model of two volumes of water, it seems
to me that when they are poofed together, they will initially be under as
much pressure as it would take to compress water to half its volume, and
that pressure would decrease as the water expanded. If you take water
under pressure, eg, from the seafloor, and turn it loose, it's under
huge pressures just beforehand, but even a very teeny expansion casues
the pressure do drop off very quickly. So you don't get an explosion.
But how deep would you have to go to get water at half-volume? And what
happens if this pressure continues (ramping down, but continuing) until
the volume has doubled? Force times distance (using the pressure and
expansion to get these, and making some simplifying assumption about
how pressure-times-surface-area would decrease with volume) would say
how much energy is released; I don't know what the pressure would be,
though. (Where would one look up the pressure required to compress
water to half its volume? pv=nrt since at those pressures it's probably
misleading to think of the water as a "liquid" in any meaningful sense?)
But I suspect the energy release would be larger than you seem to suspect.
Wayne Throop thr...@sheol.org http://sheol.org/throopw
Erik Max Francis
> And for the same reason, when you fire a gun, the bullet
> gets pushed forward out of the barrel by expanding gases
> and then the bullet drops to the ground just outside the muzzle.
>
> No, the expansion of volume is accompanied by a
> conversion of potential energy into kinetic energy. This
> energy doesn't just magically disappear once the
> expansion has stopped.
Sure. The question is how much energy is actually involved. For the
question _I_ was answering -- a person teleporting into a sofa -- the
answer is not going to be very much.
> Yes, but I was specifically talking about spheres of water.
> With an aerogel, the energy release should be small.
> After all, it takes very little work to squeeze a volume of
> aerogel into half the original volume.
>
> With water, I expect the situation to be very different.
> It's hard to physically squeeze a volume of water
> into half the original volume.
Yes, for water, the energy release is likely to be pretty large.
Water's bulk modulus B is 2.2 GPa, and bulk modulus is
B = -V dp/dV
This is in response to applied pressure, not internal pressure, hence
the negative sign. So the change in pressure resulting from an internal
volume change would be
dp = B (dV/V).
dV/V is the fractional increase the volume of the water, and dp would be
the resulting increase in pressure. Worst case, this doubles (so dV =
V) so
p = B = 2.2 GPa.
above and beyond the ambient pressure of 100 kPa (which is in comparison
negligible). As for the energy content of the water at this point,
p = dF/dA
Acting through a distance this relates work and volume by
p = dW/dV.
Knowing rho = dm/dV, we can solve for dW/dm and get
dW/dm = p/rho
for p = 2.2 GPa and rho = 2000 kg/m^3 (it's double the density now),
that gives you an internal energy of about 1 MJ/kg. So yeah, nothing to
cough at.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
Never contend with a man who has nothing to lose.
-- Baltasar Gracian
Wayne Throop
: Sure. The question is how much energy is actually involved. For the
: answer is not going to be very much.
A lot of the compressibility of the sofa is largely because it's got
lots of voids inside it. But take cloth fibers or wood cellulose or the
such; they are going to be very hard to compress. And of course, the
human body is mostly water. So while you could push the sofa materials
aside and squeeze the air out of them, if you take the volume of the
wood and fibers aside from the air, that's going to act much like a
similar volume of water; that is to say, you should be getting a similar
energy-per-kilogram-in-the-overlap-region as water interpenetrating,
though far less energy-per-liter-overlap.
Or so it would seem to me.
If it were two sofas... then it gets more compilcated, since each
non-air-void region in the sofa/human case is going to collide, but not
in the sofa-sofa case.
Erik Max Francis
> Erik Max Francis <m...@alcyone.com>
>
> > It really depends on the specifics. For a human and a sofa, the
> > result would be mighty gross and wouldn't be fun to watch (and even
> > less fun to experience), but I don't think you're talking "explosion"
> > level energetics. You could certainly choose scenarios where it would
> > be quite energetic, I'm sure.
...
> But how deep would you have to go to get water at half-volume? And what
> happens if this pressure continues (ramping down, but continuing) until
> the volume has doubled? Force times distance (using the pressure and
> expansion to get these, and making some simplifying assumption about
> how pressure-times-surface-area would decrease with volume) would say
> how much energy is released; I don't know what the pressure would be,
> though. (Where would one look up the pressure required to compress
> water to half its volume? pv=nrt since at those pressures it's probably
> misleading to think of the water as a "liquid" in any meaningful sense?)
It's the bulk modulus, B = 2.2 GPa. To get deep enough in water to
reach that pressure, you'd have to go down over 200 km.
> But I suspect the energy release would be larger than you seem to suspect.
I was specifically asking a question about a very specific scenario, one
that even you don't think would be energetic. Teleport a guy into a
sofa and he'll die, but you won't get anything remotely like an
explosion. In the paragraph of mine you quoted above, I explicitly
acknowledged that you could choose situations where there would be huge
energy releases. The apparent miscommunication here is that I was
asking someone else's question, whereas you seemed to want me to be
answering _your_ question.
Sure you can pick cases where the effects would be very energetic. The
question that was being asked, and which I answered, wasn't one of them.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
Behind an able man there are always other able men.
-- (a Chinese proverb)
rap...@netscape.net
Erik Max Francis wrote:
> for p = 2.2 GPa and rho = 2000 kg/m^3 (it's double the density now),
> that gives you an internal energy of about 1 MJ/kg. So yeah, nothing to
> cough at.
That is pretty close to my BOE calculation of 300kJ/kg. In fact using
my estimate of multiplying by 5 due to extra compression gives,
1.5MJ/kg which is even closer :).
Erik Max Francis
> A lot of the compressibility of the sofa is largely because it's got
> lots of voids inside it. But take cloth fibers or wood cellulose or the
> such; they are going to be very hard to compress. And of course, the
> human body is mostly water. So while you could push the sofa materials
> aside and squeeze the air out of them, if you take the volume of the
> wood and fibers aside from the air, that's going to act much like a
> similar volume of water; that is to say, you should be getting a similar
> energy-per-kilogram-in-the-overlap-region as water interpenetrating,
> though far less energy-per-liter-overlap.
Cloth fibers and cellulose are hard to compress? Huh?
As I said before, yes, human beings are mostly water. But that waters
is not contained in the form of a reservoir that can interpenetrate when
they teleport into each other; it's contained in the form of tissues.
Bones are hard and ostensible seem hard to compress, but they're also
porous and contain voids. These things are what count in determining
whether there will be significant overpressure in the
human-teleporting-into-sofa case.
Yes, teleport a vat of water into another vat of water and you'll get a
large energy release. But not teleporting a human into a sofa.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
rap...@netscape.net
Wayne Throop wrote:
> Well, returning to the simpler model of two volumes of water, it seems
> to me that when they are poofed together, they will initially be under as
> much pressure as it would take to compress water to half its volume, and
> that pressure would decrease as the water expanded. If you take water
> under pressure, eg, from the seafloor, and turn it loose, it's under
> huge pressures just beforehand, but even a very teeny expansion casues
> the pressure do drop off very quickly. So you don't get an explosion.
Compressing water to 90% of normal volume requires 3000A. This means
that from 0.5 to 0.9 the pressure is at least. It would drop fast, but
that also means that is climbs fast as the volume decreases.
IsaacKuo
Erik Max Francis wrote:
>Wayne Throop wrote:
>>A lot of the compressibility of the sofa is largely because it's got
>>lots of voids inside it. But take cloth fibers or wood cellulose or the
>>such; they are going to be very hard to compress. And of course, the
>>human body is mostly water. So while you could push the sofa materials
>>aside and squeeze the air out of them, if you take the volume of the
>>wood and fibers aside from the air, that's going to act much like a
>>similar volume of water; that is to say, you should be getting a similar
>>energy-per-kilogram-in-the-overlap-region as water interpenetrating,
>>though far less energy-per-liter-overlap.
>Cloth fibers and cellulose are hard to compress? Huh?
If you don't count the voids, yes. In the places where there's
actual overlap, it's the overlapping of hard to compress solids
and liquids.
>As I said before, yes, human beings are mostly water. But that waters
>is not contained in the form of a reservoir that can interpenetrate when
>they teleport into each other; it's contained in the form of tissues.
Huh? The interpenetration occurs because of the nature of the
instant teleportation. I'm not sure what you're getting at.
>Bones are hard and ostensible seem hard to compress, but they're also
>porous and contain voids.
Human bones are filled with marrow. The only major voids which
come to my mind are the lungs.
>These things are what count in determining
>whether there will be significant overpressure in the
>human-teleporting-into-sofa case.
>Yes, teleport a vat of water into another vat of water and you'll get a
>large energy release. But not teleporting a human into a sofa.
Isaac Kuo
Erik Max Francis
> If you don't count the voids, yes. In the places where there's
> actual overlap, it's the overlapping of hard to compress solids
> and liquids.
And the pressure involved causes the them to expand in into the cavities
and voids, where it encounters more material and the expansion is
halted. Like I said all along, a "foomp," not an explosion.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
There is nothing wrong with sobriety in moderation.
-- John Ciardi
Wayne Throop
: And the pressure involved causes the them to expand in into the cavities
: halted. Like I said all along, a "foomp," not an explosion.
Yes, I can see that; you've got less energy per volume, maybe 10 or 20
percent of the water-to-water energy per volume, and that volume has
all the fibers and tissues and stuff throughout it to act as a sort of muffle.
I still wonder wwhat it would look like. Maybe... as if you had very fluffy
guncotton (instead of compressed into a dense wad...), or maybe a bit
less spectacular than that.
I suspect it might disassemble pretty thoroughly, at least in the
interpenetrating region, if not spectacularly. That is, left with
puree of glop, rather than a gruesome mostly-solid mass.
But that's just guessing.
Gilbert
I don't think there will be an explosion like in "explosion", i.e.
fire, heat, smoke, big bang etc. I'd imagine it more like you'd hit an
orange hard with a sledge hammer. At least with a human body and
another "wet" object unlike a sofa, a sofa would just be "soaked". I
don't think there will be nuclear reactions, since the very same
electrostatic forces that binds and seperates atoms and molecules would
already forbid the materialization of these within each other, because
what is teleportation? It's matter transmitted as energy and somehow
focused and forced back into shape. And the assumpted energy beam of a
single molecule would be diverted/deflected by an already existing,
solid molecule, shortly before and during rebuilding.
Which brings me to the nature of this "beaming". All the energy that is
meant to be the matter of the teleported object has somehow got to get
from A to B. If it will be one single beam, and reconstructing will be
from the center of the teleported object outward, displacement of the
object that was already in the position of the teleported matter would
even be less disruptive (speaking of milliseconds here!), less
"explosive". And additionally, talking of an "ultimate weapon", that
energy beam having all the energy which contains all the nuclear power
to reform all the molecules would be "sizzling hot". I must add that
should the teleported matter be transmitted via another (mathematical)
dimension I'm out of the game and would just assume the infamous
"poof!" (but even modern, reallife teleportation experiments of
teleporting a single atom/molecule here in Vienna stay in our known and
usual dimension IIRC). If the nature of teleporting has been discussed
and taken as prerequisite here, I'm missing the point, so plase be so
kind as to give me some pointers/urls, thx.
Tim McGaughy
Whaaaa?
There are ALWAYS neutrons in every element except hydrogen.
Fission isn't initiated by a neutron "popping out". It's started by a
random neutron DECAYING. If there's another neutron in line with one of
the particles sprayed out from the original destroyed neutron, it also
can be triggered to decay.
Erik Max Francis
> Whaaaa?
>
> There are ALWAYS neutrons in every element except hydrogen.
>
> Fission isn't initiated by a neutron "popping out". It's started by a
> random neutron DECAYING. If there's another neutron in line with one of
> the particles sprayed out from the original destroyed neutron, it also
> can be triggered to decay.
I'm not sure what you're talking about here. A fission chain reaction
isn't triggered by neutrons decaying into particles which trigger more
neutrons to decay into more particles, etc. It's caused by neutrons of
a certain energy inducing a nuclear reaction in a heavy nucleus which,
in addition to fissioning into several smaller daughter nuclei, as well
as releasing energy, also emits a few neutrons of the right energy,
which encounter more _heavy nuclei_ in the same manner, and so on. Pack
them tightly enough and the fissioning leads to a runaway effect, hence
a fission explosion.
What you seem to be referring to above is beta decay, where a neutron
(in a nucleus) decays into a proton, an electron, and a neutrino (an
electron-antineutrino, actually). It's called beta decay because the
atomic number increases by one (a neutron becomes a proton).
This is the same process under which neutrons in isolation also normally
decay, so there's nothing special going on here. It has nothing to do
with chain reactions or neutron "slamdancing around." And fission chain
reactions have nothing to do with any process you're describing.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 20 N 121 53 W && AIM erikmaxfrancis
For a promise made is a debt unpaid.
-- Robert W. Service
Mad Bad Rabbit
into a volume of air, would the entire block oxidize at once?
--
>;k
Wayne Throop
: Hmm. If you teleported a block of solid aluminum (or wood, etc.)
: into a volume of air, would the entire block oxidize at once?
Air of equal volume would supply only... hm... well, unless I've dropped a
decimal, something like 1 part in 10,000 of the oxygen needed to oxydize
"the entire block" of aluminum[1]. Possibly one atom in 10,000 would be
bound up in oxides, but I wouldn't count that as "the entire block".
[1] Air is something like 1/2000 as dense as aluminum, you need
something like equal masses of aluminum and oxygen to make Al2O3,
and air is only 1/5 oxygen. Again, unless I've dropped a decimal
or something like.
Andy
The more interesting question is what happens to you if you teleport into
even a fair vacuum - all of a sudden you have foreign particles appearing
randomly thruout your body. Ow.
If you teleport into an earth-style atmosphere, you'd likely get something
akin to an instantaneous version of the bends along with massive
malfunctioning of your neurons. I'd prefer not to think about that. :)
Unless, of course, you can somehow magically clear your way ahead of
you ;-) Lots of "teleportation" in scifi seems to work that way, there's an
"air displacement" during the occurrence. The only way that makes sense is
if the air molecules are physically shoved aside by some mysterious
side-effect of the teleportation, before the actual displacement of the
mass occurs. Of course, this has massive military applications.
If you teleport into solid rock or it's like, you are dead. Might be
merciful. I'll leave the nuclear reactions to someone else, but I'd imagine
it'd be like sitting on a nuke when it goes off. One moment you're there,
the next you aren't ;-)
*shrug* ;-)
--
A
"You won't sh-"... Bravo, Lee :)
Aaron Denney
On 2006-02-05, Andy <an...@NOFRAKKINSPAM.spe.midco.net> wrote:
> Unless, of course, you can somehow magically clear your way ahead of
> you ;-) Lots of "teleportation" in scifi seems to work that way, there's an
> "air displacement" during the occurrence. The only way that makes sense is
> if the air molecules are physically shoved aside by some mysterious
> side-effect of the teleportation, before the actual displacement of the
> mass occurs. Of course, this has massive military applications.
The other common option is to exchange whatever is at where you're going
with where you currently are.
--
Aaron Denney
-><-
Andy
Which leads to many other story arcs ;-)
But isn't that the same thing as removing the target area? ;-)
rap...@netscape.net
Andy wrote:
> Aaron Denney wrote:
>
> > The other common option is to exchange whatever is at where you're going
> > with where you currently are.
> >
>
> Which leads to many other story arcs ;-)
>
> But isn't that the same thing as removing the target area? ;-)
It would prevent transporting into a quarantine area.
Dave H.
"Andy" wrote
>
> The more interesting question is what happens to you if you teleport into
> even a fair vacuum - all of a sudden you have foreign particles appearing
> randomly thruout your body. Ow.
>
> If you teleport into an earth-style atmosphere, you'd likely get something
> akin to an instantaneous version of the bends along with massive
> malfunctioning of your neurons. I'd prefer not to think about that. :)
>
> Unless, of course, you can somehow magically clear your way ahead of
> you ;-) Lots of "teleportation" in scifi seems to work that way, there's
> an
> "air displacement" during the occurrence. The only way that makes sense is
> if the air molecules are physically shoved aside by some mysterious
> side-effect of the teleportation, before the actual displacement of the
> mass occurs. Of course, this has massive military applications.
>
>
> If you teleport into solid rock or it's like, you are dead. Might be
> merciful. I'll leave the nuclear reactions to someone else, but I'd
> imagine
> it'd be like sitting on a nuke when it goes off. One moment you're there,
> the next you aren't ;-)
>
I agree, teleporting into a "fair vacuum" or an atmosphere might just result
in the equivalent of Caisson Disease ("The Bends") due to the sudden
appearance of gases within the body tissues - *all* the body tissues. A
near-vacuum shouldn't be too bad, but on entering atmospheric pressure gas
it would immediately start fizzing out as if the sufferer had surfaced in
an emergency from around 30ft / 10m depth in water - it would almost
certainly rupture the eardrums immediately (no time for the Eustacian tubes
to shed the excess), the lungs would have a hard time (don't hold your
breath!) as they'd have double their capacity of gas, the excess gases in
the bones would fizz out gently (but probably painfully) - the most
significant damage would probably be in the brain, though, as excess gases
sought a path of least resistance into the vascular system...
If you were doing it and intending to survive, a very thin atmosphere would
be best to hit, with a way of very rapidly dumping gas into a receiving
chamber (similar to a divers' decompression chamber?) to equalise pressure
immediately after arrival?
Dave H.
(The engineer formerly known as Homeless)
Gilbert
space, the higher the difference between the masses (like 1m3 gas and
1m3 water), the more energy would be used (E=mc2?!). So, if you're
exchanging the exact same mass, the needed energy would be minimal. Too
trivial?
Luke Campbell
Erik Max Francis wrote:
> As has been mentioned, even very dense materials are mostly composed of
> empty space.
As someone who has been performing computer simulations of the
electronic structure of condensed matter and molecules for the last
decade, I must say that the space between the nuclei is not very empty.
It is just crammed full of electrons. You can't say the electrons are
tiny and only occupy a small part of that space, because the electrons
are spread out into quantum wavefunctions and occupy all of that space.
Sure, most of the mass is located in tiny little regions (the nuclei),
but all the energy for chemical bonding is spread throughout the whole
volume of the solid and that energy is quite significant compared to
our everyday life - it is what powers our bodies and our automobiles,
it is what we need to overcome to break a metal bar or wooden door, and
it is what causes problems when bombs go off or bullets go through us.
A rough estimate of the amount of energy you get by suddenly putting a
volume of water (say) inside another volume of water can be obtained by
considering the water in what is called the "jellium" model - ignore
the nuclei except insofar as they act to neutralize the electric charge
of the electrons. We'll ignore the two core electrons of the oxygen as
well - they are so tightly bound they don't take up much space. The
remaining 8 electrons per water molecule we will assume are
structureless - they float around in a free electron gas. The
electrons will be highly degenerate at any reasonable temperature, much
like the matter in white dwarf stars (this model of electrons is quite
useful for predicting the properties of metals. For insulators like
water it is only approximate, and ignored details like chemical bonding
and whatnot, but should be good enough to get rough estimates). Using
this model, I get the valence electronic energy in uncompressed liquid
water is about 90 kJ per cubic centimeter. This energy increases as
the density to the 5/3 power, so doubling the density gives you about 3
times the electron energy, or 270 kJ/cm^3. Two grams of double density
water has 270 kJ. The stable form of two grams of water is two cubic
centimeters at 1 g/cm^3, or 180 kJ. The difference, 90 kJ, is
liberated upon expansion. Note that 90 kJ/gram is roughly 20 times
the energy released by detonating TNT. I would say that would produce
a very powerful explosion if even moderate quantities of material were
involved. Just for yuks, note that the pressure is p=dE/dV ~ 90 kJ/1
cm^3 = 9E10 Pa = 900,000 atmospheres.
Luke