OC.Trei%CU20B@sri-unix.UUCP (04/20/84)
From: Peter G. Trei <OC.Trei@CU20B> After seeing a lot of casual talk on this board about the Death Star and its ability to blow up planets, I decided it was time to get a little more specific. Just how much energy does it actually take to blow up, say Earth (we dont have the stats for Alderan). For the sake of argument, I have defined a planet as being 'blown up' when its fragments are receding from its original location fast enough so that they will never coalesce again. In effect, the entire mass of the planet has to be accelerated to its own escape velocity. Using the back of a very large envelope, this is what I came up with. (I hope someone checks these figures). Earths density : 5.52 g/cm^3 Diameter: 12,757 km Escape velocity: 11.3 km/s => vol = 1.087 E13 km^3 mass = 6 E25 kg => Need 3.8307 E33 Joules to blow up. (Of course, this ignores the planets structural strength, and assumes 100% efficiency in production of kinetic energy with the appropriate vectors.) Thats a lot of EverReadys. What could be the source of this energy? Can the Death Star hold that much? The answer is yes, if they use mass conversion at high efficiency. Here is the calculation for the mass equivalent of that energy: 1 kg = 9 E16 Joules (from E = mc^2) => need 4.2555 E16 kg of mass. If this mass is at the same density as the Earth, you will require 8100 Km^3 of it. In one lump, this is a spheroidal rock about 25 Km across. Of course, it gets smaller if you use lead, or neutronium. Some people have been saying that the DS is '100 miles' across. I find this difficult to accept. From its appearence in the movies, I would have said that its diameter was 5-10 miles at the outside. This obviously leads one to wonder where they keep (a minimum of) 4 E16 kg of ammo, and still leave room inside for spacefighter dogfights. Even using antimatter does'nt really help, at best it improves your ammo's effiency by a factor of two. I am forced to the conclusion that the DS's main weapon is not sending out all of that energy itself. Somewhere along the line more energy is being produced, and delivered to the target. The 'chain reaction' hypothesis thus appears. I can think of two ways to do this: 1. Induced fusion. Back when they were testing the first thermonuclear weapons out in the Pacific, some people entertained serious worries that the shock wave of the bombs would induce fusion in the light water of the Ocean, leading to a chain reaction in which all the hydrogen of the Earth would fuse. Also, think of the current work on inertial confinment laser induced fusion. I have heard that the Antares laser produces (momentary) flashes of 4 E19 watts. 2. Matter conversion ray. In one of his Known Space stories, Larry Niven had a weapon, the ray of which would convert anything it touched to energy. Even on an airless moon, you could see the ray because of the destruction of interplanetary gas. At one point the protagonist accidently allows the ray to intersect the horizon, causing a major earthquake. It would be just dandy as a planet destroyer (BTW, this was a HAND WEAPON!). Peter Trei oc.trei%cu20b@columbia-20.arpa PS: I wonder how many times in the past someone has actually done this calculation! Hail Eris! PT -------
markv@dartvax.UUCP (Mark Vita) (05/10/84)
About the Death Star weapon...
I don't know if I am thinking of the same Niven weapon or not,
but in one of his Known Space stories ("World of Ptavvs"), the
Slaver uses a weapon which neutralized the charges on the electrons
in the atoms of whatever matter it touched. The result was
that the atoms blew themselves apart by electromagnetic repulsion,
leaving a cloud of subatomic dust. (It's really gruesome when
he uses it on living flesh.)
Anyone care to speculate on the plausibility of this weapon?
It seems like it should work. My only question was -- how about
the strong nuclear force in the atom? I thought that this force
was much stronger than the electromagnetic force at distances
on the order of an nuclear radius.
--
Mark Vita
Dartmouth College
{decvax,cornell,linus}!dartvax!markvlmc@denelcor.UUCP (Lyle McElhaney) (05/14/84)
Anyone care to speculate on the plausibility of this weapon?
It seems like it should work. My only question was -- how about
the strong nuclear force in the atom? I thought that this force
was much stronger than the electromagnetic force at distances
on the order of an nuclear radius.
The strong nuclear force does indeed hold the nucleus together. There seems
to be confusion between the nucleus and the atom itself. The weapon
neutralizes the charges on the electrons, which become something very
like small-mass neutrinos, and they leave the scene to the unshielded
nuclei. These disperse due to their mutual magnetic repulsion. They do
not themselves disintegrate, presumably because the weapon does not affect
their magnetic repulsion/strong force attraction balance. The radius of
effect of the strong force is on the order of the size of the nucleus; the
size of an atom (its electron shells) is several orders of magnitude greater
and the strong force has no role in keeping the electrons with the nucleus.
The plausibility is the same as for FTL, thiotimoline, and the radio in
Galileo's day - impossibly small *at this time*. Later on, who knows?
--
Lyle McElhaney
(hao,brl-bmd,nbires,csu-cs,scgvaxd)!denelcor!lmcfish@ihu1g.UUCP (05/14/84)
Yes, the strong nuclear force IS much greater than the electromagnetic
force, which is why nuclear weapons make such a big noise. I still
contend that the Death Star weapon starts a nuclear chain reaction at the
target, but I don't know how you could do it. Assuming that Alderan was
made up of iron and silicates, etc, there isn't much readily fissionable
or fusionable material around.
I don't think a weapon that could neutralize the electrostatic charges
is feasible, but a proton beam would be just as effective. Trouble is,
the effect would be local.
--
Bob Fishell
ihnp4!ihu1g!fishsteven@qubix.UUCP (Steven Maurer) (05/17/84)
> The plausibility is the same as for FTL, thiotimoline, and the radio in > Galileo's day - impossibly small *at this time*. Later on, who knows? <sputter sputter foof> FTL is *IMPOSSIBLE* DO YOU HEAR ME???? YOU HAVE A BETTER CHANCE AT MAKING A PERPETUAL MOTION MACHINE THAN YOU HAVE AT MAKING AN FTL DRIVE!!!! <foof sputter sputter> I find it somewhat humorous (in a sick sort of way) that people who are supposed to be as intelligent as SF readers, can totally ignore the findings of Einstein -- without even bothering to read or understand them. What Einstein discovered, is a new (UNBREAKABLE) law: much like the Second Law of Thermodynamics. And ALL THE FUTURE SCIENCE IN THE WORLD, will not change it, or allow one to get around it somehow. The "hyperspace" excuse, arises from an incomplete understanding of what Einstein discovered: you cannot "go around" the distance, because the very act of APPEARING at a place before light gets there, is exactly equivalent to going backwards through time. Steven Maurer
jonab@sdcrdcf.UUCP (05/17/84)
In article <1104@qubix.UUCP> steven@qubix.UUCP (Steve Maurer) writes: > > <sputter sputter foof> > FTL is *IMPOSSIBLE* DO YOU HEAR ME???? > YOU HAVE A BETTER CHANCE AT MAKING A PERPETUAL MOTION MACHINE > THAN YOU HAVE AT MAKING AN FTL DRIVE!!!! > <foof sputter sputter> assert(flame). People who live in grass huts shouldn't throw flames! Before you flam at someone, make sure you know what you are talking about also. > I find it somewhat humorous (in a sick sort of way) that people > who are supposed to be as intelligent as SF readers, can totally > ignore the findings of Einstein -- without even bothering to read > or understand them. I find it humorous (in a sad sort of way) that people who are supposed to be as intelligent as USENET news readers ;-} can totally ignore the findings of Einstein -- without even bothering to read or understand them. 1) There is no intelligence prerequisite to reading SF or USENET news. People who read SF tend to be above average in intelligence, but that is not necessarily so. Your flame is only an ad hominim attack against someone who was posting an article in fun anyway. > What Einstein discovered, is a new (UNBREAKABLE) law: much like > the Second Law of Thermodynamics. And ALL THE FUTURE SCIENCE IN > THE WORLD, will not change it, or allow one to get around it > somehow. Let's examine what Einstein "discovered": Einstein didn't discover anything in his Theories of Relativity. What he did was postulate a new physical world view based on a couple of simple postulates. 1) The laws of physics are unchanged with respect to any observer in a inertial reference frame. 2) The speed of light is measured as a constant for all observers. First, we must realize that Relativity is only a very well substantiated theory. No one has and probably no one EVER will prove it as true. The second postulate above, is one of the laws of physics mentioned in the first postulate. However, that postulate only comes from the observations of researchers in the late 19 century, not as a fact handed down by divine inspiration. These observers have only been able to make their measurments of the speed of light in a non-inertial reference frame, where all bets are off and the Special Theory of Relativity does not apply. Thus, we don't even know what physics is like in a TRUE inertial reference frame, because we don't live in one, and no matter where we go, we will NEVER find one. (There is always an acceleration due to gravity that makes the fram non-inertial, no matter where we go.) So Relativity can be called a very good guess. > The "hyperspace" excuse, arises from an incomplete understanding > of what Einstein discovered: you cannot "go around" the distance, > because the very act of APPEARING at a place before light gets > there, is exactly equivalent to going backwards through time. If you assume that travel by hyperspace is the process of leaving normal space and re-entering elsewhere, then Relativity precludes that form of travel, IF the theory is true. (Actually I wonder whether the theory holds up when one takes it to the limit with singularities like infinite velocity.) If hpyerspace travel is, instead, a method of changing the laws of physics in the local area of space, (such as increasing the speed of light in a limited area), then Relativity could hold and yet from an outside observer, it would appear that one was travelling faster than light. (The observer would probably see you arrive before you left, but that can happen even when you travel at less than the speed of light because of acceleration. retract(flame). PLEASE, PLEASE, PLEASE, do not think that just because a new Theory has been discovered that changed or disproved the old theories, then it must be true. We have only extended our knowledge of the universe, we have not proved that there is nothing more to be learned. Jon Biggar {allegra,burdvax,cbosgd,hplabs,ihnp4,sdccsu3}!sdcrdcf!jonab P. S. If you are wondering what my qualifications are, I have a B. A. in Engineering/Physics. However, I would need many, many more years of study before I could fully appreciate the works of Einstein. That stuff is hard to read!
kechkayl@ecn-ee.UUCP (05/18/84)
#R:sri-arpa:-1253700:ecn-ee:14400006:000:732 ecn-ee!kechkayl May 17 17:25:00 1984 >What Einstein discovered, is a new (UNBREAKABLE) law: much like >the Second Law of Thermodynamics. And ALL THE FUTURE SCIENCE IN >THE WORLD, will not change it, or allow one to get around it >somehow. My, my, my! Such vehemence! I guess we have discovered someone that does not know that it is the THEORY (hint: !law) of Relativity. I thought that one of the basics of the scientific method was that theories can (and must) be changed to fit newly discovered facts. If something is discovered that contradict the THEORY, the theory must be changed to cover the fact. ALL you can say is that the theory appears to describe reality fairly well. Thomas Ruschak pur-ee!kechkayl "Aiee! A toy robot!"
hennessy@nmtvax.UUCP (05/18/84)
qubix!steven states > What Einstein discovered, is a new (UNBREAKABLE) law: much like > the Second Law of Thermodynamics. And ALL THE FUTURE SCIENCE IN > THE WORLD, will not change it, or allow one to get around it > somehow. This unfortunalely is not the case. What Einstein did was create a new formulation of mechanics that works better than Newtonian Mechanics in some situations. When you don't fool around with velocities close to the speed of light old Newton is fine. When tested in areas, for example: the mass increase of electrons at SLAC, Einsteins calculations prove very good. However, no how many experiments confirm a law it only takes one differing experiment to invalidate this law for those areas. Science dosen't make the universe what it is. Science is an attempt to predict what will happen based on previous observations of the universe. Remember Clarke's law. You never know. Sincerely; Greg Hennessy ..ucbvax!unmvax!nmtvax!hennessy or ..ucbvax!unmvax!nmtvax!student
sharp@kpnoa.UUCP (05/19/84)
Poor Einstein is much maligned. See my article on time machines in net.physics.
Relativity queries accepted, but remember I make my living by understanding
both general and special relativity. Not that they're flawless ...
--
Nigel Sharp National Optical Astronomy Observatories
Tucson, Arizona (602) 325-9273
UUCP: {akgua,allegra,arizona,decvax,hao,ihnp4,lbl-csam,seismo}!noao!sharp
ARPA: noao!sharp@lbl-csam.arpajim@ism780.UUCP (05/21/84)
#R:sri-arpa:-1253700:ism780:14200007:000:1782 ism780!jim May 19 22:15:00 1984 > My, my, my! Such vehemence! I guess we have discovered someone that > does not know that it is the THEORY (hint: !law) of Relativity. You have a false notion of what a theory is. I suggest you check the dictionary. No matter how well validated, the theory of relativity will never be called a law, yet almost all astrophysicists accept it. > I thought that one of the basics of the scientific method was that > theories can (and must) be changed to fit newly discovered facts. > If something is discovered that contradict the THEORY, the theory > must be changed to cover the fact. Fine, but no one has offered any new facts to contradict the General Theory of Relativity. And there is not even the faintest sign of a theory which can account for all observed evidence (another basic of the scientific method: a new theory must subsume the old theory; anything explainable under the old theory must be explainable under the new theory) and yet does not accept the speed of light as a limiting factor. > ALL you can say is that the > theory appears to describe reality fairly well. The GR explains a great number of interlocking, otherwise very peculiar observations in a very natural fashion (the theory itself is structurally simple and free of ad hoccery, such as "tired photons", if you have been following net.physics), and has accurately predicted (ability to predict is another fundamental of a theory according to scientific method) many phenomena. This goes way beyond describing reality "fairly well". The fact of the matter is that the odds that GR is correct are very high, and romantic notions such as FTL are just that. As Carl Sagan has said (about ESP and such), "it would be *wonderful*, *if* it were true". -- Jim Balter, INTERACTIVE Systems (ima!jim)
chris@ism780.UUCP (05/21/84)
#R:sri-arpa:-1253700:ism780:14200008:000:1192 ism780!chris May 20 11:26:00 1984 <we got bugs, right here is river city!> I am a little surprised that people with scientific background keep ignoring the first law: "Keep an open mind". If you arbitrarily decide that something is possible or impossible, you stop looking for new evidence, and new ways of interpreting the evidence. Yes, FTL does look unlikely, Given What We Know Now. It may or may not be truly possible. However to decide that it is or is not possible on the scanty evidence we have is the same as me deciding that electrons do not exist just because i have never seen one. Twelve years ago the notion of quarks was one that wasn't taken seriously by very many people at all. Now they are taken very seriously. The whole history of scientific thought shows that what is one decade's heresy is another decade's dogma, and a third decade's popular antiquity. If you don't want to get stuck into a particular line of thought, you have to be willing to look at things from different points of view, and see how things look from there. Isn't that after all the essence of Relativity? What you see depends on where you stand. Chris Kostanick decvax!vortex!ism780!chris decvax!cca!ima!ism780!chris
kcarroll@utzoo.UUCP (Kieran A. Carroll) (05/23/84)
* I agree! The very act of appearing in a place before light has a chance to get there (you know what I mean) is exactly equivalent to going back in time. Now tell me; what so bad about going backwards in time? -Kieran A. Carroll ...decvax!utzoo!kcarroll
cem@intelca.UUCP (Chuck McManis) (05/24/84)
Actually this refers to a previous note that FTL travel was/is IMPOSSIBLE.
Humans, especially sci-fi types have never considered ANYTHING impossible.
Einstien(sp?) was a brilliant physicist and mathematician however the
theory of relativity (general and special) are his best effort at explaining
our universe. Granted they are very good, and much evidence supports it,
however, the same could be said of the central earth theory back in
Galileos time. The only way you can advance you're theoretical sciences
is to NOT believe its impossible and try to explain why it isn't. I know
that with current technology/theories FTL is impossible but that does
not prevent me from attempting to supercede or improve on current science
to show that it is.
-never say never -
--Chuck
P.S. Some very respected scientists in aerodynamics were publicly saying
that C. Yagers jet would disentegrate if it broke the sound barrier.steven@qubix.UUCP (06/01/84)
weapon.
Organization: Qubix Graphic Systems, Saratoga, CA
Lines: 35
[ * ]
I agree! The very act of appearing in a place before light has a chance to
get there (you know what I mean) is exactly equivalent to going back
in time.
Now tell me; what so bad about going backwards in time?
-Kieran A. Carroll
...decvax!utzoo!kcarroll
===================
Well, nothing, except that there is no evidence for it.
I realize that this is a pretty lame excuse to have hanging
around in net.sf-lovers, HOWEVER most sci-fi has FTL without
(for some inexplicable reason) time travel. To name a few:
Star Trek, Star Wars, Niven, Heinlein, MZ Bradley, CJ Cherryh, Pohl,
Asimov, etc., etc., etc. While I have no explicit objection to
the "science" in many stories by Dr. Who (even though exceedingly
improbable, they are at least possible), I would point out that
most science fiction is patently false. (But what if 2 + 2 DID
equal 5??).
Steven Maurer
... As it is, psionics promises to be even funnier than dianetics or Ray
Palmer's Shaver stories. It suggests once more how far from accurate is the
stereotype of the science fiction fan as a bright, well-informed, scien-
tifically literate fellow. Judging by the number of Campbell's readers who
are impressed by this nonsense, the average fan may very well be a chap in
his teens, with a smattering of scientific knowledge culled mostly from
science fiction, enormously gullible, with a strong bent toward occultism,
no understanding of scientific method, and a basic insecurity for which he
compensates by fantasies of scientific power. -- Marvin Gardenerlmc@denelcor.UUCP (Lyle McElhaney) (06/02/84)
> > The plausibility is the same as for FTL, thiotimoline, and the radio in > > Galileo's day - impossibly small *at this time*. Later on, who knows? > > <sputter sputter foof> > FTL is *IMPOSSIBLE* DO YOU HEAR ME???? > YOU HAVE A BETTER CHANCE AT MAKING A PERPETUAL MOTION MACHINE > THAN YOU HAVE AT MAKING AN FTL DRIVE!!!! > <foof sputter sputter> > > {skip the inuendo} > > What Einstein discovered, is a new (UNBREAKABLE) law: much like > the Second Law of Thermodynamics. And ALL THE FUTURE SCIENCE IN > THE WORLD, will not change it, or allow one to get around it > somehow. You are, of course, absolutely correct. Einstein said so, Asimov says so, every physicist I've ever read says so. And yet... After saying so, stridently, in one of his monthly columns, Isaac Asimov followed up the next month with a column of the shearest speculation on what might be possible. Robert M. Powers in "The Coattails of God" says "If rearranging the distances to the stars is not easy to do, there may be ways in which the barrier of the speed of light may be broken...[it] is a tentative "possibility"." To be sure he makes it very doubtful that such may come to pass. I find it very difficult to be as dogmatic as your statement above; but then I'm an engineer, not a physicist (or philosopher, which may be a better judge). As Clarke (Heinlein?) has said, "If a highly placed scientist says that something is possible he is very likely correct; if he says that something is impossible, he is very likely wrong." Of course, that probably doesn't say anything about your position. -- Lyle McElhaney (hao,brl-bmd,nbires,csu-cs,scgvaxd)!denelcor!lmc
bsafw@ncoast.UUCP (Brandon Allbery) (06/04/84)
You err in stating that Star Trek did not have time travel with FTL. In one episode (sorry, I watched most of the episodes when I was 6 -- I re- member the storylines but not the titles) they used FTL around a gravity well to achieve time travel. This may imply an unusual mechanism for FTL which does NOT violate Einstein's mechanics. -- -------------------------------------------------------------------------------- Brandon Allbery decvax!cwruecmp!ncoast!bsafw "...he himself being one universe's prime MCI MAIL: 161-7070 example of utter, rambunctious free will!" USMail (core dump): 6504 Chestnut Road Independence, OH 44131