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Antimatter and Antistars?

payndz asks: "I'm currently writing an SF novel, and came up with a weird thought for a piece of background flavour that, if there's any scientific basis for it, might get expanded into a larger element. The most up-to-date theories for the creation of the universe 13.7 billion years ago (give or take...) suggest that at the Big Bang, matter *and* antimatter were created. Over time, the fact that there was slightly more matter than antimatter means that mutual annihilation has left a universe of matter. (I'm not going to open up the whole can of 'dark matter' worms, unless somebody wants to...). I have a 'what if' question, which since Hubert Farnsworth isn't around I thought would get some good responses here: what if, rather than antimatter being annihilated by matter in the universe at large, there are 'clumps' of both matter and antimatter making up the universe? Since our clump is almost entirely matter, billions of LY away could there be galaxies made up of antimatter?More to the point, what physical properties would these galaxies have? Would a star made of antimatter function in the same way as a matter star, and would its emissions be made of antiparticles? Can you have anti-photons, and if you could, what impact would they have on any matter they illuminated? Could life evolve in an antimatter environment?"

156 comments

  1. silly constraints by chewy · · Score: 1, Interesting

    Since you are writing fiction, it doesn't really matter whether it's real at all or not. All real physics are only just theory, so anything you can dream of should be possible in your fantasies!

    1. Re:silly constraints by Lshmael · · Score: 3, Insightful

      But he isn't writing a fantasy, he is writing science fiction. Therefore, his "constraints" are valid, since they are what define the genre. For example, writing about a flat earth should not be considered true science fiction, for the simple reason that it is quite unlikely that the earth is flat. Standard scientific opinion is that the earth is round. While it is true that much of astrophysics is "theory," it is educated theory.

    2. Re:silly constraints by chewy · · Score: 1
      " writing about a flat earth should not be considered true science fiction"


      Fortunately I don't see Terry Pratchett as SF either :)

      But there are scifi (Bladerunner, some Iain Banks books, Neuromancer. Matrix) which directly contradicts true "facts" or known science, yet are still called scifi. My point is rather that one shouldn't try to make something fit inside some "genre". Write what fascinates and compells you.
    3. Re:silly constraints by AndyElf · · Score: 1

      What are the true facts of known science that are directly contradicted in Bladerunner? Same with Neuromancer. Suggesting things that are beyond "known science" is not, necessarily, a contradiction.

      --

      --AP
    4. Re:silly constraints by sql*kitten · · Score: 4, Insightful

      But he isn't writing a fantasy, he is writing science fiction. Therefore, his "constraints" are valid, since they are what define the genre.

      Actually, the thing that matters in scifi is consistency. You can make up the rules, but once you have you have to stick to them, otherwise your stories disintegrate into deus ex machina handwaving. That is why Star Trek is bad scifi* - the capabilities of all its technological artifacts change from episode to episode, and they can always "technobabble" their way out of any situation. In Star Trek, technology is indistinguishable from magic. Far, far better is the work of Alastair Reynolds - he does use technologies which don't yet exist, but his characters are forced to work within fixed limitations (i.e. humans colonize the nearby stars relying on relativistic time dilation and suspended animation - there is no FTL, and anyone who tries it fails, no matter how useful it might be for the story).

      --
      * However it can be good drama, it's not scifi even tho' it's in space.

    5. Re:silly constraints by pmz · · Score: 1

      That is why Star Trek is bad scifi* - the capabilities of all its technological artifacts change from episode to episode, and they can always "technobabble" their way out of any situation.

      I don't think Star Trek was ever intended to be great Sci Fi. The original series pushed the then-modern social envelope more than anything. It really wasn't until the 1990's that it decomposed into a politically-correct serial.

    6. Re:silly constraints by gseidman · · Score: 1
      "writing about a flat earth should not be considered true science fiction"

      Fortunately I don't see Terry Pratchett as SF either :)

      I recommend Terry Pratchett's Strata, which is science fiction and deals rather scientifically with a flat Earth.

    7. Re:silly constraints by FesterDaFelcher · · Score: 1

      Yeah, and Idaho is really a state. http://kuoi.asui.uidaho.edu/idaho_does_not_exist.h tml

      --
      My user number is prime. Is yours?
    8. Re:silly constraints by Radical+Rad · · Score: 2, Funny
      Since you are writing fiction, it doesn't really matter whether it's real at all or not. All real physics are only just theory, so anything you can dream of should be possible in your fantasies!

      You're Dubya's speech writer, aren't you???

    9. Re:silly constraints by anetic · · Score: 0

      I take it that you never saw Dark City ?

  2. Don't land on one :-) by oren · · Score: 5, Informative

    Larry Niven had this great short story where Elephant looks for the most unusual piece of real estate in the known space... nicknamed "Cannonball", it is a solar system zooming *very fast* through our galaxy. While that is unusual by itself, it isn't the *most* unusual thing about it, as you can guess.

    Luckily for him his pilot is a coward, so they don't land :-)

    Seriously, the existrance of large amount of anti matter (whole galaxies of it) isn't _that_ far fetched. Consider that the original big-bang universe is made out of hot plasma. A blob of matter pressed against a blob of anti matter will create a terribly violent reaction in the interface zone; this would act as a "wall" repelling both matter and anti-matter away from it, preserving them as seperate regions. Also, any electrical current flowing through the plasma will tend to separate matter and anti-matter. Given the whole universe is expanding madly in the duration it is possible that ant-matter "islands" survived.

    AFAIK (IANAP) anti-matter galaxies/stars would be indistinguishible from normal-matter ones. Photons don;t care whether they are created by matter fusion or anti-matter fusion, etc.

    1. Re:Don't land on one :-) by Anonymous Coward · · Score: 0
      Luckily for him his pilot is a coward, so they don't land
      YOU TAKE THAT BACK! Bey Shaeffer is emphatically not a coward - look at how he behaves in Grendel. He's merely a much more experienced spaceman than Elephant, and knows the difference between bravery and foolhardiness.
    2. Re:Don't land on one :-) by Tukla · · Score: 1

      I can't remember...did he make his "no landing" decision before or after the GP hull went *poof*?

    3. Re:Don't land on one :-) by rokzy · · Score: 1

      "AFAIK (IANAP) anti-matter galaxies/stars would be indistinguishible from normal-matter ones. Photons don;t care whether they are created by matter fusion or anti-matter fusion, etc."

      an anti-matter world would look mostly the same, but you could tell it apart from a matter world using kaon decay rates - matter/anti-matter symmetry is not exact.

    4. Re:Don't land on one :-) by ajs · · Score: 1

      The GP hulls were always my favorite Niven idea (though flash-crowds were pretty cool). The idea of a single-molecule macroscopic structure is just so freaky that I *want* to see one! :)

    5. Re:Don't land on one :-) by Anonymous Coward · · Score: 0

      A blob of matter pressed against a blob of anti matter will create a terribly violent reaction in the interface zone; this would act as a "wall" repelling both matter and anti-matter away from it, preserving them as seperate regions.


      Except that isn't what happened. There weren't separate blobs of matter and antimatter coming into contact with each other; the matter-antimatter annihilation occurred before that. Matter and antimatter were completely mixed together at the level of individual particles.
    6. Re:Don't land on one :-) by RedCard · · Score: 1

      The idea of a single-molecule macroscopic structure is just so freaky that I *want* to see one! :)

      Here's one you've seen before: A diamond.

      Any diamond - a pure one - is a crystalline structure of carbon atoms, and hence any diamond, no matter how large is a single molecule.

      Doesn't seem so freaky anymore, does it?

    7. Re:Don't land on one :-) by ajs · · Score: 1

      A crystalline structure is not quite the same as, say, a single strand of polymer, 200 miles long, and wound into a space-capable spherical hull.

  3. Don't go there by the_DaRKaNGLe · · Score: 3, Funny

    It has been done before, about a million times in one form or another. Somhow this article triggered some Startrek flashback...

    --




    A problem cannot be solved at the same level of awareness that created it.
    1. Re:Don't go there by Anonymous Coward · · Score: 0

      Somhow this article triggered some Startrek flashback...

      Made me think of an episode of the animated ST series featuring an antiuniverse with black stars and white space. Simply recalling the memory of that series gives me involuntary shudders...

  4. Larry Niven thinks so... by Thornae · · Score: 3, Interesting

    There's a Larry Niven short story called Flatlander which deals with the concept of antimatter stellar objects - only briefly, but it's worth a read.
    Also, wander up to your nearest university and look up the astro-physics department. Chances are there'll be a couple of knowledgable types in there who could point you in the right direction.

    --
    |>
    Here be Dragons
  5. Physical properties of antimatter galaxies by baywulf · · Score: 4, Funny

    "Since our clump is almost entirely matter, billions of LY away could there be galaxies made up of antimatter?More to the point, what physical properties would these galaxies have?"

    One thing is for sure. There would be a person identical to you except they would have a goatee and no sleeves on their uniform.

    1. Re: Physical properties of antimatter galaxies by Black+Parrot · · Score: 5, Funny


      > One thing is for sure. There would be a person identical to you except they would have a goatee and no sleeves on their uniform.

      That's how everyone looks here. Where the heck are you posting from?

      --
      Sheesh, evil *and* a jerk. -- Jade
    2. Re:Physical properties of antimatter galaxies by n1ywb · · Score: 1

      Goatee == EVIL
      Like, from the NEGAVERSE

      --
      -73, de n1ywb
      www.n1ywb.com
    3. Re:Physical properties of antimatter galaxies by fliplap · · Score: 1

      "I'm tired of parallel Bender lording his cowboy hat over me!"

    4. Re: Physical properties of antimatter galaxies by op00to · · Score: 1

      How terrible! A world full of goatses!

    5. Re: Physical properties of antimatter galaxies by Paul+d'Aoust · · Score: 1

      ha ha. nice try, bud. I bet you were just waiting for an opportunity like that, weren't you? ^_^

      --
      Standing at the very edge of my imagination, I peered into the inky void and realised -- I couldn't think up a new sig.
    6. Re:Physical properties of antimatter galaxies by Unordained · · Score: 1

      luckily for us, Spock's logic remains the same ... anti-logic? bah!

    7. Re: Physical properties of antimatter galaxies by Anonymous Coward · · Score: 0

      This is why I love slashdot. :)

  6. Some info as i remember by Sklivvz · · Score: 5, Informative

    First of all, there's basically no difference between a galaxy (or a physical body) made of matter and antimatter... Actually you wouldn't be able to tell. The major physical difference is the charge of particles (e.g. anti-electrons, or positrons, have +ve charge) but of course you wouldn't be able to tell since you would call +ve charge -ve and vice versa.

    Secondly, according to the theories you mentioned, there's basically very little chance that large lumps of antimatter were formed during the big bang, since most of the annihilation would have taken place at a stage when all the matter was condended in a very small place, and therefore the distribution of antimatter would be quite uniform (so you wouldn't have a galaxy of am here and one of normal matter there).

    Thirdly, there are no antiphotons. Photons are the antiparticles of themselves!

    Hope it helps!

    1. Re:Some info as i remember by McCarrum · · Score: 1

      I'm sorry .. this is so lame .. but your sig is just fantastic.

      Oh ghod, what have I become .. a sig fanboy ..

      M

    2. Re:Some info as i remember by cthugha · · Score: 4, Insightful

      Not only that, but it would seem that any clump of A-M of less than galactic size would have a hard time existing in a harsh, matter-filled region. A-M objects in an M galaxy would have to contend with the fact that interstellar space isn't empty, but has a faint hydrogen "wind" blowing thorugh it. For an inert body like an asteroid or rogue planet, this would mean gradual but inevitable erosion. For a star system, things might get interesting, since the star's own solar wind would sweep the interstellar medium out to its heliopause, which would presumably show up as a gamma-ray "halo" surrounding the system.

      I wouldn't even want to speculate on the conditions necessary for the formation of such a system, since I'm simply talking out of my rear-end here (I Am Not An Astrophysicist).

    3. Re:Some info as i remember by Gyl · · Score: 2, Interesting
      This could be an interesting effect for a sci-fi. Assume the universe is large enough to hold pockets of matter and anti-matter, then the regions between these pockets may be highly active areas of near empty space where matter and anti-matter collide and release lots of energy. Like a sort of second cosmic microwave background, though it probably wouldn't be microwaves.


      Could be fun designing a starship to cross this boudry.

    4. Re:Some info as i remember by canadianjoe · · Score: 1

      That'd be kind of interesting, could look something like a kind of large "planetary" nebula.

    5. Re:Some info as i remember by Yrd · · Score: 1

      One condition for the possible existance of an anti-matter galaxy in a region of matter galaxies: some crackpot alien race built the thing.

      I have no idea why they might want to, and very little conception of where they'd get the energy to do it, but these silly thoughts occur to me sometimes.

      --
      Miri it is whil Linux ilast...
    6. Re:Some info as i remember by PurpleBob · · Score: 1

      Congratulations, you've crossed the matter/antimatter boundary with a starship. Now what do you do?

      I mean, you're sure as heck not going to land anywhere.

      --
      Win dain a lotica, en vai tu ri silota
    7. Re:Some info as i remember by Anonymous Coward · · Score: 1, Funny

      Congratulations, you've crossed the matter/antimatter boundary with a starship. Now what do you do?

      I'm going to Anti-Disney World!!

    8. Re:Some info as i remember by Gyl · · Score: 1
      well, that's for the story writer to decide.


      You know how scientists have lots of trouble producing even tiny amounts of anti-matter. Where better to get copious amounts of the stuff? Could be used for such things as alternative energy source, or removing planets to make way for hyperspace bypasses.

    9. Re:Some info as i remember by L10N · · Score: 0

      The thing is, I feel exactly the same way. Imagine" "reading /. posts in near boredom numbness...sights the Charm of Making! Suddenly remembers an awesome movie, feels complelled to tell wife who is on a computer right beside me...wife shrugs and fains a smile...posts .sig fan post..."

      And there ya go...I'm thinking machines are evil, I need to go live in the woods in tent for a few weeks.

      FEAR SKYNET!

      --
      "What we do in life echoes in eternity." Maximus Decimus Meridius
    10. Re:Some info as i remember by aminorex · · Score: 1

      > since most of the annihilation would have taken place at a stage when all the matter was condended

      ah, but annihilation releases energy, and the energy would
      also have been extremely condensed, leading to the
      formation of new matter, in equal proportions of charge.
      this is during the period of rapid inflation, at the end of
      which, i speculate, equilibrium between matter creation
      and destruction existed. by that time, clumping had
      already occurred, corresponding to galatic superclusters.

      hey, it's plausible. i haven't tried the numbers, though.

      --
      -I like my women like I like my tea: green-
    11. Re:Some info as i remember by GigsVT · · Score: 1

      As a permanant defense against war and invasion?

      After all, we are talking about premises for a Sci-Fi book here. If the aliens could somehow come up with a technology to convert matter to anti, it would be a great shield against invasion. At least until some other race discovers it.

      --
      I've had enough abrasive sigs. Kittens are cute and fuzzy.
    12. Re:Some info as i remember by Yrd · · Score: 1

      Maybe, but they would also make themselves very vulnerable to any other race outside their conversion field who happened to get hold of a lot of disposable matter and chuck it through their galaxy. Might take a while, but you could annihilate every significant installation if you wanted to. If you assume that one race develops the technology to perform such an anti-matter conversion, it seems reasonable that some other race would be able to develop the technology to use stars as projectile weaponry.

      --
      Miri it is whil Linux ilast...
    13. Re:Some info as i remember by Doom+Ihl'+Varia · · Score: 1

      I think stars as projectile weaponry would be a bit of a problem for anybody, regardless of matter/anti-matter.

  7. holy shit by Anonymous Coward · · Score: 0

    gimme some of whatever ur smokin. please

    i haven't add any thoughts that mind provoking for a LONG time.

  8. Re:one observation by gsergiu · · Score: 0

    Yeah, i've noticed that kind of beaviour in a scientist. "If I can't see it, it's not there" . Well, a lot o theories are based on this simple fact, and i think that it is wrong. It's basically, like the premise that the universe is expanding. I don't know if this is true. It is expanding for us. Every year the universe is bigger with a light year. But i think is normal. But it doesn't mean that it really expands. Only we *think* it does. I think scientist could get over the facts that you see, and the facts that can be, only need to be proven to be out there.

  9. Re:one observation by mishac · · Score: 1

    there is so such thing as an anti-photon...photons are their own anti-particle. An antimatter star would emit regular photons. Sorry dude.

  10. Shameless Plagiarism by benjamindees · · Score: 5, Insightful
    (picks up "Six Not-So-Easy Pieces" by Richard Feynman next to computer)

    In this fundamental physics book, Feynman describes all of the states of physical matter and the laws of symmetry that go along with them. When discussing the right and left-handed rules, he asks the obvious question of whether they are arbitrarily chosen; whether right-handed means anything other than in opposition to left-handed. He asks this to spur our interest in discovering the basis for the symmetry of physical laws.

    To illustrate, he imagines a conversation between a human and a distant alien, the purpose of which is for the human to communicate to the alien, after describing the human body and anything else of import, which hand is the left and which is the right, in order to know on which side to place the human heart. After dismissing a few possible physical phenomena by which this information could be conveyed, Feynman describes an instance (during a weak decay of a cobalt nucleus) in which the emitted electron always has a left angular momentum. This, he says, can be used to indicate to our alien friend which is left and which is right. Hold onto that for a second...

    In the next section, he describes antimatter. He first theorizes that, other than annhilating each other on contact, objects made entirely of antimatter would not be noticeably different from those made of matter: It is one of the principles of the symmetry of physics, the equations seem to show, that if a clock, say, were made of matter on one hand, and then we made the same clock of antimatter, it would run in this (exact same) way. He then adds the example of the left-handed beta decay above by constructing a theoretical antimatter clock made of cobalt nuclei. He speculates that since left and right-handed matter clocks could be constructed to behave differently, thus violating the law of mirror symmetry, that antimatter clocks would also behave dissimilarly depending upon their handedness.

    He goes through all of that to simply tell us that a left-handed matter clock is equivalent in every way to a right-handed antimatter clock. Unfortunately for sci-fi novelists, changing matter to antimatter merely alters the handedness of the particles, rather than actually violating symmetry or having any other noticeable effect. Of course, his lectures are no longer cutting-edge and the book only gives a laymans description of the underlying physics, but it doesn't look too good.

    Feynman ends up concluding:

    So, if our Martian is made of antimatter and we give him instructions to make this "right" handed model like us, it will, of course, come out the other way around. What would happen when [...] we each have taught the other to make space ships and we meet halfway in empty space? We have instructed each other on our traditions, and so forth, and the two of us come rushing out to shake hands. Well, if he puts out his left hand, watch out!

    --
    "I assumed blithely that there were no elves out there in the darkness"
    1. Re:Shameless Plagiarism by kmak · · Score: 1

      Exactly. If we lived in an "anti-matter" world, we would've have noticed, and would've just had different textbooks..

      --

      I'm not the devil.. just his advocate.
    2. Re:Shameless Plagiarism by jiahao · · Score: 1, Informative

      Check out CPT violation on the net. Feynman is 40 years out of date on this topic.

    3. Re:Shameless Plagiarism by SEWilco · · Score: 2, Funny
      Check out CPT violation on the net. Feynman is 40 years out of date on this topic.

      He is having difficulty getting his updates past the Editor.

    4. Re:Shameless Plagiarism by Glock27 · · Score: 1
      He goes through all of that to simply tell us that a left-handed matter clock is equivalent in every way to a right-handed antimatter clock. Unfortunately for sci-fi novelists, changing matter to antimatter merely alters the handedness of the particles, rather than actually violating symmetry or having any other noticeable effect. Of course, his lectures are no longer cutting-edge and the book only gives a laymans description of the underlying physics, but it doesn't look too good.

      Hmmm. I was going to say that perhaps left-over antimatter from the Big Bang was the source of "dark energy" that is inferred from recent Hubble observations. That struck me as a very bizarre result.

      If antimatter repelled everything, including itself, then there couldn't be astronomical objects made of antimatter. I suppose another possibility might be that antimatter attracts itself (normal G law) but repels normal matter, and vice versa. This would tend to segregate the universe into distinct matter/antimatter regions.

      Interesting stuff. Never forget that we live in an object more exotic than a black hole (the universe).

      --
      Galileo: "The Earth revolves around the Sun!"
      Score: -1 100% Flamebait
    5. Re:Shameless Plagiarism by CTachyon · · Score: 1

      Actually, antimatter has real, positive mass, so it behaves identically to matter w.r.t. gravity. Antimatter not only attracts itself gravitationally, but it also attracts matter (and vice versa). To get gravitational repulsion, you would need some form of matter with negative mass (at least for Newtonian physics).

      --
      Range Voting: preference intensity matters
  11. Anti-photons by Anonymous Coward · · Score: 0

    Photons are their own anti-particles, so yes and no, there are anti-photons, photons.

    -- Paul Tötterman ( I would have logged in, but I'm at work)

  12. Re:one observation by keesh · · Score: 2, Informative

    Which ignorant asshole modded him up? He doesn't have a clue what he's on about. Anti-photons *are* photons.

  13. Heyyyy by Anonymous Coward · · Score: 1, Funny

    I am fucked up and that was quite the idea for a book. I consider it quite entertaining.

  14. photons by BoxedFlame · · Score: 2, Informative

    The equations that describe matter and anti-matter have identical solutions for the case of photons, meaning that anti-photons and photons are the exact same thing. This is logical since if they were not then what would photons and anti-photons react to create?

    1. Re:photons by Anonymous Coward · · Score: 0

      what would photons and anti-photons react to create?

      Kaphlooey-ons?

  15. Re:one observation by sql*kitten · · Score: 3, Interesting

    we don't see anti-matter photons hitting our telescopes, therefore anti-matter stars do no exist...

    I'm pretty sure that a photon from a matter-antimatter reaction is the same as a regular photon, and that gamma radiation from said reaction is just regular gamma radiation also, not "anti-gamma". Therefore, I don't think anti-hydrogen fusion is going to be that different from regular hydrogen fusion. I don't think you would be able to tell the difference between a matter and an antimatter star just by looking at it, you'd have to get close enough (or observe something made of matter that got close enough) to get caught in its solar wind (anti-hydrogen is definitely different from regular hydrogen, see).

  16. Matter in Reverse by Associate · · Score: 0

    I recall reading somewhere that animatter is what matter would be but traveling the oposite direction in time. Hell, what do I know? I count boxes for a living.

    --
    Someone hates these cans.
    1. Re:Matter in Reverse by EvilSporkMan · · Score: 1

      Alice in Quantumland, perhaps?

      --
      -insert a witty something-
  17. The thing about antimatter... by Anonymous Coward · · Score: 0

    ... is that it is indistinguishable from normal matter. The interesting thing is when matter and antimatter particles interact (come into contact with each other). They are both annihilated, leaving behind a ball of energy according to Einstein's E = m * c^2 equation.

    So if you meet your antimatter-self, don't shake hands with him! The only thing that would be left is a giant crater in the ground.

    Maybe that could be the plot for a sci-fi novel, a world full of matter and antimatter people carefully avoiding each other :)

  18. WTF? Do your own research! And protect yourself! by WIAKywbfatw · · Score: 5, Insightful

    Seriously, some recent Ask Slashdot's have been ridiculous - doesn't anyone know how to use Google, etc anymore?

    This one takes the biscuit though. You're a writer (or want to be) - at the very least you should be able to do your own research for your work!

    Posting an Ask Slashdot is a very bad idea, for at least two reasons:

    1. There's no way you can easily distinguish between accurate and inaccurate statements.

    Just because something quotes a scientist or it's been modded up it doesn't make it any more reliable then anything else.

    2. You leave yourself open to litigation.

    George Lucas makes a point of not looking at Star Wars fan fiction because he doesn't want to leave himself vulnerable to the guy who'll scream "Hey, you stole that scene/character/whatever in Episode III from my story!". You might not have billions to lose but by canvassing for information and ideas so publicly you're still leaving yourself wide open to that sort of allegation.

    You might think that Slashdot is an open forum, populated by open source advocates who would all be opposed to intellectual property litigation and would do nothing more than help out and wish you luck but it'll only take one asshole to prove you wrong.

    Someone's bound to mod this down as flamebait or as a troll but if you're going to be an author then you can't afford to ignore this stuff.

    --

    "Accept that some days you are the pigeon, and some days you are the statue." - David Brent, Wernham Hogg
  19. differences by AntiNeutrino · · Score: 1

    firstly (obviously) all particles would be exchanged for antiparticles. That means that in the star, anti-protons would fuse to anti-helium releasing electron-neutrinos (as opposed to our sun releasing anti-electron-neutrinos)
    [this is an effect of the weak interaction]

    note also: a poton is it's own antiparticle, this the stars would shine just like ours do.
    gravity wise you wouldn't be able to tell the difference either. paricles and anti-particles have the same gravitational mass...

    I'm sorry but I don't think an anti-matter setting for your book would be particularly interesting or exotic...

    perhaps if there are sentient (anti)beings who realise that they are overpowered by matter and live in constant fear of being anhilated *grin*
    (...makes more for dark kind of scifi ...)

    anyway,
    good luck

    AntiNeutrino

    --
    I can't even remember what it was I came here to get away from - Bob Dylan
  20. Yum by sporty · · Score: 4, Funny

    Just don't put the pasta near the anti pasta. That could be bad.

    /rimshot

    --

    -
    ping -f 255.255.255.255 # if only

    1. Re:Yum by Anonymous Coward · · Score: 0

      But if Italians are able to eat the anti-pasta right before the pasta, does that mean that they have two separate stomachs? It kind of sounds plausible, considering that cows have four stomachs.

  21. Re:one observation by Zachary+Kessin · · Score: 3, Informative

    The anti particle of a Photon is a photon. However if you had an anti-mater star, it would probably be blindingly obvious. Stars emit photons, but they also blow off a stellar wind of other particles (electrons, protons etc) If it was an anti star as soon as this stuff hit the intersteller media (that loose collection of hydrogen and other stuff between the stars) it would react in a stream of gamma rays around the star.

    --
    Erlang Developer and podcaster
  22. just do it, worry more about the plot.. by gl4ss · · Score: 3, Insightful

    it doesn't REALLY matter if theres some sillyness from physics point of view(hyperjump is one) as far as the book tells a good story and is intresting otherwise, has good flow of text and other things that make a book a great book. keep the sillyness logical and constant though, _DON'T_ fall into explaining every little tidbit how it works and how it is possible unless it's essential from viewpoint of some character in the book(or similar).

    most great scifi books/ short novels could have been just as easily setted in non typical scifi setting(heinleins starship troopers could be set without much fuss into ancient greek), bad scifi is where the 'scifi' is used just to cover up something else, like the lack of plot or bad writing. though, one can use the story to tell of a world to come and it can work pretty well, and predict possibilities of technology, but without good storytelling these are just academical papers on possible future.

    and most things that apply to scifi apply to fantasy too, mostly because underneath they are pretty much the same for most authors, it doesn't really matter if the lockpick is a complicated electronic hacker gadget or a spell, or if you use a robot instead of a demigod as an ageless being watching over humanity for thousands of years.

    --
    world was created 5 seconds before this post as it is.
    1. Re:just do it, worry more about the plot.. by SEWilco · · Score: 1
      sillyness from physics point of view(hyperjump is one)

      An antihyperjump moves you a very short distance?
      Or it moves you a very great distance in a time longer than it would take to travel there in real space?

    2. Re:just do it, worry more about the plot.. by Anonymous Coward · · Score: 0

      "most great scifi books/ short novels could have been just as easily setted in non typical scifi setting"

      I disagree.

      Paul Atreides could not have shaken the universe anywhere else but Arrakis, and I doubt that we'd find Bilbo Baggins anywhere else but the Shire.

      For every thousand stories that could have taken place anywhere, there is a single epic that could only take place in the world that the author has envisioned. Never take the setting for granted.

      "it doesn't really matter if the lockpick is a complicated electronic hacker gadget or a spell, or if you use a robot instead of a demigod as an ageless being watching over humanity for thousands of years."

      And if Paul Atreides had shot fireballs from his eyes and bolts of lightning out of his arse on the plains of Arakeen, Dune would not be Dune. If Legolas had pulled out an AK-47 and layed into a legion of Uruk-Hai, The Lord of the Rings would not be The Lord of the Rings.

    3. Re:just do it, worry more about the plot.. by gl4ss · · Score: 1

      you don't quite get it don't you? dune could have been quite easily set in medieval europe, or ancient rome, of course the environment would change but those don't matter that much. you could set dune in a 1960s midwestern farm for gods sake. just take the plot up and downs and change everything accordingly and keep it constant, if legolas had an ak47 his name would probably have been dimitri and the whole story set in late 20th century, in which case it wouldn't have seemed that strange he had an ak47, the ring could have been a vial of some disease, drugs or bomb, the shire could have just easily been some backwater town(or a planet) too. now, some people do just read books because theyre scifi, fantasy, cheesy love or other, and buy them too, but that's like watching scifi channel just because it is scifi channel, not caring what the program actually is. there are other reasons too for setting the story in a scifi setting, like getting through censorship(why do you suppose so much good scifi came from eastern europe?) or prompting some social issues to come whilst telling a good story. disneys treasure planet is in it's own way an example of this, it's the same old treasure island story in a mildly different setting, donald duck comics common in europe use this kind of alternate setting for already known story _very_ often. three musketeers could be setted easily in modern los angeles(and has been) and still be the same story underneath albeit with a different setting, name and characters.

      --
      world was created 5 seconds before this post as it is.
  23. Some differences by Lady+Jazzica · · Score: 5, Funny

    There are a few differences between an antimatter galaxy and a matter galaxy like our own. For instance, in an antimatter galaxy, the element Antimony is called "Mony". They use it as a means of facilitating the exchange of goods and services. Also, in antimatter England, they drive on the right side of the road.

    1. Re:Some differences by Anonymous Coward · · Score: 0

      Almost everyone in England has heard this joke: You yanks may drive on the right side of the road, we drive on the correct side.

    2. Re:Some differences by MagikSlinger · · Score: 1
      Also, in antimatter England, they drive on the right side of the road.


      "Be careful with that [matter inversion gizmo]... we could end up undoing unthings untogether!

      -- Doctor Who, John Pertwee

      --
      The bitter lessons of a veteran coder: http://bitterprogrammer.blogspot.com
    3. Re:Some differences by Anonymous Coward · · Score: 0
      I place this idea under the GPL. Take it, use it, extend it, or print it out and use it for toilet paper.
      Please don't do the latter. Remember, under the GPL, if you release something based upon a GPL work, you're obliged to share it all with everyone.

      I don't really want you sharing your used toilet paper.

    4. Re:Some differences by Anonymous Coward · · Score: 0

      Of course, we tell a joke here about the English: they let their guns get taken away, just like the Jews let Hitler take their guns away.

    5. Re:Some differences by Anonymous Coward · · Score: 0

      In antimatter russia YOU drive CAR!

  24. Strong constraints exist from gamma rays by pfdietz · · Score: 5, Interesting

    Observation of annihilation gamma rays places strong constraints on the amount of antimatter in the universe. For example, we can confidently say that most of this galaxy is normal matter. Were this not the case, annihilation of matter and antimatter gas in interstellar space would produce too much annihilation radiation at 511 keV (electron/positron annihilation) and at ~100 MeV (photons from neutral pion decay.)

    IIRC, the smallest scale at which antimatter can dominate is galactic superclusters, but even that may now be ruled out.

    1. Re:Strong constraints exist from gamma rays by Bootsy+Collins · · Score: 1

      IIRC, the smallest scale at which antimatter can dominate is galactic superclusters, but even that may now be ruled out.

      I just wanted to respond to back this up; at least as of the mid-90's, you'd have to go out beyond the Local Supercluster. I haven't followed this since then, unfortunately, so I don't know what the implication of the current (GRO?) data is.

  25. Re:one observation by QNX · · Score: 0

    Get a anti-telescope and you will see it.
    Those work great also to see under the clothes. ....Mmmm, that would be a good story....Anti-Telescope, Nude woman, $$$
    I should write a sc-f book about this

    --
    Karma: Very Very Very Very Bad
  26. couple of things by alexjohns · · Score: 3, Interesting
    There are no anti-photons so light from anti-matter stars looks the same as from regular stars. So you wouldn't be able to tell from that. However, somewhere there would be an interface of some sorts. A boundary where on one side is anti-matter and the other matter. This isn't a hard boundary, but if you have two galaxies, about half-way in between there would be a lot of shit going on.

    See, empty space isn't really empty. There's Hydrogen out there. There would be an amazing light show at the border. The constant meeting of matter and anti-matter (space dust, if you will, emitted by both galaxies) would most likely be very visible. Matter/anti-matter reactions are very energetic, far more so than fusion, even.

    The only way to have anti-matter galaxies in your universe is if they were more than 13.7 billion light years distant, so the light from the interface hasn't reached us yet. Or maybe there could be a single anti-matter galaxy somewhere out there, discovered by the weird light reaching us from that corner of the universe. I doubt our telescopes have looked everywhere, yet.

    Aside from all that, science is just a hook. As long as you're internally consistent, it doesn't matter if your science is far-fetched. Plot, characters, story. Interesting things happening to interesting people will be what sell books. I probably didn't need to tell you that. I still read a lot of old sci-fi that has bad science in it. 'Lensmen', Heinlein juveniles like 'Tunnel in the Sky', 'Citizen of the Galaxy', and 'Starman Jones', Campbell's 'Arcot, Morey, and Wade' stories. Love that stuff.

    1. Re:couple of things by dfranks · · Score: 2
      I am suggesting this as a story line, not as real physics, but since we are seeing signs that dark matter/energy exhibits a repulsive force of some kind, how about if dark matter was "neutral matter" that did not react with M or A-M except through it's repulsive force. This could implement the buffer between the M and A-M galaxies and explain the lack of observed annihilation events between the galaxies.

      Just an idea...

  27. Nobody here reads Greg Bear? by borgboy · · Score: 3, Interesting

    In Anvil of Stars, Bear introduces a civilization so advanced that they could manipulate vast ammounts of matter over large distances and convert M objects to A-M. Including people. The human's who were converted to A-M died slowly because their organic chemistry was subtly different. Made for a nasty suprise when the pilots tried to re-dock with their mother ship.

    Not that this represents anything based in reality or the laws of physics. Just "prior art" from a respected hard sci-fi writer.

    --
    meh.
    1. Re:Nobody here reads Greg Bear? by jafuser · · Score: 1

      Another fun trick for someone with an advanced enough technology would be to rotate someone in 4D space, so their left and right are switched.

      I am quite curious as to how this would alter their perception. Would everything look backwards to them?

      --
      Please consider making an automatic monthly recurring donation to the EFF
    2. Re:Nobody here reads Greg Bear? by Anonymous Coward · · Score: 0

      Ohhhh....that makes my brain twitch.

  28. Alternate Galaxies by Anonymous Coward · · Score: 0

    The Weak Beta Decay can be used to determine the handedness of the galaxy, as described above.
    However, there is a further interesting twist. It seems that theoretically it is possible to have alternate universes based on mirror symmetry. In this theory there are both ordinary and mirror particles (not to be confused with anti-particles). For example, even the photon would have a mirror particle.
    Ordinary and mirror particles would interact only via gravity. This would explain the "missing mass" problem of "dark matter".
    There is even a web page dedicated to this: http://www.geocities.com/mirrorplanets/
    The main proponent seems to be R. Foot at the University of Melbourne.
    I'm sure you can get some ideas for an SF novel from this!
    H. Sandin
    (theoretical physicist)

  29. Mad Max 4 by PaddyM · · Score: 1

    Matter vs. Anti-Matter

  30. So, by pmz · · Score: 1

    in this anti-galaxy, would there be anti-comedians? Would everyone's boss be an anti-asshole? I'm getting dizzy...

    1. Re:So, by eoyount · · Score: 1

      No, that would be next door in the bizarro galaxy.

      --
      To understand recursion,
      you must first understand recursion.
  31. My thoughts on the physics. by Randolpho · · Score: 0

    First, let me say IANAP. I'm also basically brainstorming; if this, then maybe that.

    So... what is antimatter? It's matter whose particles have an opposite charge from the particles we know as matter. A matter proton has a positive charge. An antimatter proton (negaton?) has a negative charge. A matter electron has a negative charge. An antimatter positron has a positive charge.

    What would antimatter be like?

    The first thing I can think of is that antimatter electricity (positricity?) will flow in the opposite direction. All things that depend upon the charge of electricity, for example, say, magnetic attraction, will be reversed. Matter north would attract antimatter north, and repel antimatter south, and vice-versa.

    Also, electromagnetism would be reversed. With matter, magnetic fields generated by an electric current follow the left-hand rule. Magnetic fields generated by a positric current would follow the right-hand rule.

    Here's something to think about that follows: light emitted by antimatter, because the electric and magnetic fields are generated in reverse, would be inverted in frequency/wavelength.

    hmm....

    Would antimatter tend to absorb high-frequency light (uber-ultra-violet) and permit low-frequency (infrared) to pass through, rather than the reverse with matter? That would mess up traditional scanning techniques... X-rays would warm an anti-matter person up, while IR light would act like an X-ray....

    Oh, and viewing antimatter would be like the ultimate acid trip. Colors would be fucked up indeed. Normal antimatter stars would probably be the same, since they tend to emit light in all wavelengths, but the interactions of matter with the light would be fucked. Light-loving plants would be red rather than green. The good guys would wear black, not white.

    That'd be something fun to write about in your book. :)

    --
    "Times have not become more violent. They have just become more televised."
    -Marilyn Manson
    1. Re:My thoughts on the physics. by Bootsy+Collins · · Score: 2, Informative

      Here's something to think about that follows: light emitted by antimatter, because the electric and magnetic fields are generated in reverse, would be inverted in frequency/wavelength.

      I have no idea what you mean by "inverted in frequency/wavelength." However, the truth is that light would be perceptibly unaffected. As correctly noted by several people here, the photon is its own antiparticle. Or, if you wish to think in terms of E-M waves, changing the sign of the E- and B-fields in an electromagnetic wave is simply equivalent to a 180-degree phase change (remember those sin/cos waves), which we wouldn't notice.

      Would antimatter tend to absorb high-frequency light (uber-ultra-violet) and permit low-frequency (infrared) to pass through, rather than the reverse with matter?

      We don't have a whole lot of experience at this point studying the atomic structure of anti-atoms. However, there's nothing at this point to cause one to expect that their atomic physics would be dramatically different from theoretical expectation: that they'd be the same as regular atoms.

    2. Re:My thoughts on the physics. by Randolpho · · Score: 1

      Hmm... yes, a phase shift makes more sense.

      Remember, I qualified my post that I was brainstorming. Clearly my storm fizzled out. ;)

      Of course... it would be fun sci-fi to conjecture that the light would be reversed.........

      --
      "Times have not become more violent. They have just become more televised."
      -Marilyn Manson
    3. Re:My thoughts on the physics. by MillionthMonkey · · Score: 1

      The first thing I can think of is that antimatter electricity (positricity?) will flow in the opposite direction. All things that depend upon the charge of electricity, for example, say, magnetic attraction, will be reversed. Matter north would attract antimatter north, and repel antimatter south, and vice-versa.

      Also, electromagnetism would be reversed. With matter, magnetic fields generated by an electric current follow the left-hand rule. Magnetic fields generated by a positric current would follow the right-hand rule.


      A magnetic field generated by an antielectron current would point the opposite way than a field generated by an ordinary electron current, that's true. But that magnetic field will have the same effects on antimatter electrons as an ordinary field does on ordinary electrons. The field direction has reversed, but so have the charges, so the motion will be the same.

      Electromagnetism is charge-symmetric. You can't determine whether you and the things in your lab are made of matter or antimatter by observing the way electrons move in a field created with a current of those same kind of electrons. In fact there is no electromagnetic experiment you can do at all to determine that. Field direction (and charge sign) are just conventions- they aren't true physical phenomena except in a relative sense. The "direction" of a field is completely determined by the decision Ben Franklin made when he picked one charge (the wrong one, too) and called it "positive".

  32. From their point of view by fok · · Score: 1

    WE are the antimatter...

    --
    \m/
    1. Re:From their point of view by Anonymous Coward · · Score: 0

      Actually, considering most of our current theories point to an overwhelming preponderance of matter over antimatter, I think we can still claim the normal, unadorned "matter".

      They'd originally think of themselves as "matter", but as they became aware that theirs was not the norm, that would change.

    2. Re:From their point of view by Anonymous Coward · · Score: 0

      You forgot to prefix your statement with "In Soviet Russia"...

  33. According to... by mcp33p4n75 · · Score: 1

    "Geometry, Relativity, and the Fourth Dimension," one possibility is that antimatter galaxies would appear to run backwards in time. Of course, to them, we'd appear as if we were running backwards in time. I'm sure you can build some neat ideas off of this.

  34. Answer... by paploo · · Score: 1

    In my upper-division cosmology classes I recall having a dicussion about this very question. It wen something like this (If my brain doesn't fail me):

    Astrophysicists had seriously toyed with the question of wether other galaxies were anti-matter. Indeed, based off of EM radiation (light), there would be no way to tell, since matter and anti-matter both emit light.

    Also, if the matter between them never interacted, there would be no way to tell, as matter and anti-matter are indistinguishable when completely segregated.

    However, there are good reasons to believe that all of the matter is normal matter (well, meaning that a negligably small amount of anti-matter is still present): Collisions between galaxies and their particles happen all the time. Indeed, even the outter extent of our galaxy is meshing slightly with Andromeda (2 million light years away). With all these collisions, one would expect that if any of these galaxies were made of anti-matter, that a reaction would occur and emmit a *lot* of high energy (which would have a signature that we could deduce from spectroscopy). But we simply don't see this occuring.

    Also, ass mentioned before in this thread, stars emit interstellar particles in the solar wind. This argument turns out to be the weaker argument, as usually stars are contained in their own galaxies, and each galaxy is probably either all matter or all anti-matter. However, this argument is a good explination of *why* each galaxy would only be either matter or anti-matter.

  35. Re:WTF? Do your own research! And protect yourself by Atzanteol · · Score: 2, Interesting

    Why doesn't anyone consider 'Ask Slashdot' to be reasearch?

    Seems like you're the only one around here crufty enough to think it isn't. Most people have been giving lucid, well-thought out responses. Then there's the "I don't like this question, so I'll bitch" troll. Come on, whine a little more about ask slashdot! You can do it!

    Wow are there a lot of whiney people on slashdot.

    --
    "Ignorance more frequently begets confidence than does knowledge"

    - Charles Darwin
  36. You Bigot! by Anonymous Coward · · Score: 0

    Antimatter and Antistars?

    What do you have against matter and stars, annyway?

  37. actually... by Anonymous Coward · · Score: 1, Informative

    What you quoted is the parity conservation. However, if you take charge into the consideration, there is a way to correctly tell a distant alien the concept of "left" and "right."

    CP (charge & parity) is violated.

  38. Mony Mony by Tackhead · · Score: 1
    > There are a few differences between an antimatter galaxy and a matter galaxy like our own. For instance, in an antimatter galaxy, the element Antimony is called "Mony". They use it as a means of facilitating the exchange of goods and services.

    So you're saying Billy Idol, to say nothing of Tommy James and the Shondells, were just a bunch of greedy aliens from this other galaxy?

    Oh, right. Roswell 1947, shortly before the popularity of rock 'n' roll... and the rise of RIAA to world dominance. It all makes sense now.

  39. Re:WTF? Do your own research! And protect yourself by Kent+Brewster · · Score: 2, Informative
    Point One is excellent; if you're serious about writing hard science fiction, please be sure to confirm any advice you receive here.

    As for Point Two ... unless 1) somebody posts detailed plot, story, or character information here, 2) you are dumb enough to include it in your book, and 3) your book is lucky enough to make it into print after you include unsolicited fan fiction in it, you should be fine. The SF writing community trades research all the time; you can see it in action over on the SFF.net or Speculations research topics.

  40. Anti-Photons by phnx90 · · Score: 1

    The anti-particle of a photon is a photon.

  41. Antistars by EdMack · · Score: 1

    You mean anti-stars, like Celine Dione?

    --
    puts ("Python r0cks\n");
  42. Check out Nobel Laureate Hannes Alfv�n by monopole · · Score: 1

    You might check out Nobel Laureate (Physics 1970) Hannes Alfvén's speculations on the matter (or antimatter). Particularly "Worlds-Antiworlds: Antimatter in Cosmology" where he supposed that matter and antimatter stars coexisted with boundary layers of plasma between them. In fact he had a running bet that Alpha Centari was made of antimatter (I once had lunch with him and heard this first person).
    To quote http://www.agu.org/sci_soc/alfven.htm :
    "Some of Hannes Alfvén's ideas are still controversial. One example is his idea that the universe consists of equal amounts of matter and antimatter separated by thin boundary layers"

    1. Re:Check out Nobel Laureate Hannes Alfv�n by anetic · · Score: 0

      Just returned from a wild goose chase trying to find Alfven's controversial theory (the link you gave was dead). but anyway at the very least learnt about Alfvern's Waves, not that I can necessarily dovetail that with anti-matter ?

  43. Anti-matter is cool, but... by hcetSJ · · Score: 1
    Although anti-matter sounds cool, proposing a universe/galaxy made entirely of anti-matter really isn't any different than a universe/galaxy of matter. What makes anti-matter anti- is that it's electric charge is reversed (or, if you ask Feynman, it's moving backwards through time--but don't get any funky ideas from that, because the 2nd Law of Thermo still guarantees that even for anti-particles entropy will increase, which is what is really driving time in the direction we call foreward). So, since anti-matter is just oppositely charged matter that means that:
    • There is no such thing as an anti-photon, since there photons do not carry charge (also, there is no such thing as an anti-neutron).
    • Anti-particles still have positive mass, so there's no such thing (at least from anti-matter) as anti-gravity (or, for that matter, anti-Catholicism).
    • An anti-matter galaxy would behave exactly like a regular matter galaxy, you'd just never be able to go there without exploding in a huge puff of pure energy.
    If science fiction is based on real science and then extends into the unknown, it's a lot better, because you aren't reading along and suddenly think, that's wrong.

    Good Luck!
    --

    This side up.
    1. Re:Anti-matter is cool, but... by chriso11 · · Score: 1

      Actually,
      There are anti-neutrons - the parameter that changes is spin, IIRC.

      As for visiting an anti-matter galaxy, you would be mostly fine (probably just a lot more radiation from interstellar particles eroding your ship's hull. Just don't try to land on a planet.

      --
      No, I don't trust in god. He'll have to pay up front, like everybody else.
    2. Re:Anti-matter is cool, but... by drxenos · · Score: 1

      there is no such thing as an anti-neutron That depends on what theory you subscribe to. One theory states that a neutron is composed of an electron and a protron. This is backed up by three observations: 1) Its mass is equal to the sum of the two. 2) It has no net charge (the charges cancel). 3) When a neutron is split apart, an eletron was observed "flying out." This is this true then although the net result is the same--a particle with no NET charge--a neutron and anti-neutron would still be different and still destroy each other.

      --


      Anonymous Cowards suck.
    3. Re:Anti-matter is cool, but... by sander · · Score: 1

      matter / antimatter is not just a charge difference, and its not true that non-charged particles don't have anti-particles. consider neutrinos.

      and of course there is a anti-neutron - what do you think you would get when a anti-proton and positron fuse ? Hadrons are made up of quarks and these have corresponding anti-quarks - from which you get not just anti-proton but also neutron and anti-neutron.

    4. Re:Anti-matter is cool, but... by Nyarly · · Score: 1
      Actually, by suggesting that the mass of a neutron is the sum of the masses of an electron and a proton, you're dodging one of the really fun little divergences in subatomic physics. There's actually a really tiny difference between M(n) and M(p) + M(e). Something like three or four orders of magnitude smaller than an electron, but the difference is there.

      His name is Neutrino. His mass is real, but he is not.

      --
      IP is just rude.
      Is there any torture so subl
    5. Re:Anti-matter is cool, but... by drxenos · · Score: 1

      Thank you. I didn't know there was a discrepancy. I was taught (about a billion years ago!) that the sum of the masses was equivalent to the mass of the neutron. Interesting...

      --


      Anonymous Cowards suck.
    6. Re:Anti-matter is cool, but... by Guy+Harris · · Score: 1
      There are anti-neutrons - the parameter that changes is spin, IIRC.

      No - neutrons have a half unit of spin, and the spin of a neutron can be "up" or "down", just as with other half-spin particles such as electrons and protons. The same is true of anti-neutrons, so a neutron and an anti-neutron can have the same spin (both "up" or both "down") or can have opposite spins (one "up", one "down").

      It's other charge-like quantum numbers, such as baryon number and isospin (unrelated to spin), that change in the neutron. (They also change in any other particle, e.g. both anti-protons and anti-neutrons have a baryon number of -1, rather than the +1 that the proton and neutron have.)

    7. Re:Anti-matter is cool, but... by Guy+Harris · · Score: 1
      Actually, by suggesting that the mass of a neutron is the sum of the masses of an electron and a proton, you're dodging one of the really fun little divergences in subatomic physics. There's actually a really tiny difference between M(n) and M(p) + M(e).

      ...just as there's a difference between the mass of a hydrogen atom and the masses of the electron and nucleus - equal to the energy it requires to ionize the atom, I think. Conservation of energy and all that.... The same applies to the mass of, say, a deuterium nucleus and the masses of the proton and neutron in the nucleus - equal to the energy it'd take to split that nucleus.

  44. Re:WTF? Do your own research! And protect yourself by Elwood+P+Dowd · · Score: 1

    George Lucas makes a point of not looking at Star Wars fan fiction because he doesn't want to leave himself vulnerable to the guy who'll scream "Hey, you stole that scene/character/whatever in Episode III from my story!".

    As much as I hate fan fiction, somehow I feel like that would make for a much better Episode III.

    --

    There are no trails. There are no trees out here.
  45. MOD PARENT UP!! by Anonymous Coward · · Score: 0
    Jeez, I love all capitals.

    Anyway, info in parent is correct while grantparent is incorrect. Antimatter is almost but not really "just" matter with a different charge.

  46. Heisenburg... by morton2002 · · Score: 1

    My favorite of all the silliness is their "Heisenburg compensator" device :)

    1. Re:Heisenburg... by Khakionion · · Score: 1

      Silly? These guys don't think so.

      --
      OMG! Wau!
  47. Respectfully disagree by Outland+Traveller · · Score: 3, Insightful

    I think it's a fine idea for people to solicit ideas on slashdot. It is an open forum, and many of the popular posts express sympathy for the free expression of ideas.

    I wish more people would do so. I don't look forward to a society where everyone is afraid to ask questions in public for fear of being sued.

    1. Re:Respectfully disagree by WIAKywbfatw · · Score: 2, Interesting

      Substitute "program" for "book" and instead of helping him with him with science let's say we're helping him with his code. Now factor in that it's not an open-source project (I'm assuming he's not going to make his novel free as in speech.

      How many people on Slashdot do you think would help someone else code a closed-source (possibly non-free) application? How is it any different because it's a book? That's partially where I'm coming from but I'm trying to be pragmatic, hence I responded with caveats rather than condemnation.

      Nevertheless, I do feel that it's rather lazy for someone to submit an Ask Slashdot for this sort of help. Far better would be approaching an academic or a postgraduate student, getting him/her on board and picking his/her brains. Most people in academia would be glad to help out for nothing more than a thank you in the author's notes, and their knowledge of the subject would undoubtably be superior.

      My criticism isn't squarely aimed at the questioner but also at the editors too. Far too many of the recent Ask Slashdot's have been completely non-technical in nature and, dare I say it, off-topic.

      Occupying Your Freetime on a Business Trip? Getting Back Into Shape While At The Office? Tooth Whitening Products? Sexual Harassment for Consultants? What if Energy was (Nearly) Free? Sports Technology? Collecting a Judgement? And those are just the ones from the last month or so.

      Haven't people heard of sites that provide travel guides, exercise resources, medical help, legal advice, etc? Worse, haven't the editors realised that some of these topics are completely inappropriate for this forum? I mean, teeth whitening? What's next, penile implants?* How long before we get asked for interesting topics to discuss over dinner?

      Ask Slashdot has become a slippery slope. Right now it looks like we're heading down it headfirst.

      (*At least penile implants aren't completely off-topic, if the amount of coverage that spam on the subject generates is anything to go by.)

      --

      "Accept that some days you are the pigeon, and some days you are the statue." - David Brent, Wernham Hogg
    2. Re:Respectfully disagree by Outland+Traveller · · Score: 1

      Heh, well some of those are good points.

      I think in this case, I was thinking, "This topic sounds interesting, lets see what people came up with for ideas."

      Pontifications on antimatter aren't something I would go out of my way to seek out. The only time I really run across these kinds of discussions is on slashdot.

      If he hadn't asked the question, I wouldn't have been able to read the answers, so I wanted to defend people who ask these kinds of questions out of self interest.

      Cheers,
      -OT

  48. DUMBASS! Where do you think Dark Jedi come from? by RobbieW · · Score: 1

    It's obvious you've never read any of the "expanded" Star wars universe books. If you did, you'd already know that the dark side of the force is fueled by "every living thing made of anti-matter."

    Dumbass!




    Sarcasm impaired people please note that this was intended to be a bad joke.

  49. Odd Cosmology... by ThosLives · · Score: 1
    Hrm. I was just thinking... when the cosmologists estimate the "age of the universe" and they say that the limit of what we can see is, oh, say 13 billion light years, do they account for the time it took for the source of said radiation to get out that far in the age of their universe? Since (supposedly) matter cannot travel anywhere near the speed of light, the universe must be several orders of magnitude older than the "oldest" light we can see, and the things we are "seeing" are really outside the edge of the visible universe.

    The only other option that I can see is that people are playing some fun games with the age/size/etc. of the universe...

    --
    "There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
    1. Re:Odd Cosmology... by drxenos · · Score: 1

      Even though for you and me and normal matter, time slows down, light exists outside of and is not affected by time.

      --


      Anonymous Cowards suck.
  50. Diff between matter and anti-matter universes by cyranoVR · · Score: 1

    Maybe I'm showing my age here, but anyone who remembers DC Comic's Crisis on Infinite Earths from the 80s knows that the primary difference between regular matter and anti-matter universes is that the anti-matter universe is EVIL!!!

  51. Negative Matter by Inexile2002 · · Score: 1

    Check out Robert Forward's "Time Master" for an interesting read on Negative Matter. (Not the same as Anti-matter.) It has repulsive instead of attractive gravity, it annihilates itself with matter producing zero energy and a bunch of other cool properties. And aparently, there is strong theoretical evidence that it might exist too.

    1. Re:Negative Matter by acgetchell · · Score: 1

      Actually, Robert Forward wrote a paper about "negative matter" as an interesting thought exercise in an inertialess propulsion. Negative matter is based upon a 1957 paper by Herman Bondi in General Relativity as a way of explaining certain concepts.

      Just like magnetic monopoles, there's no proof of the existence of negative matter. Certainly nothing you can characterize as "strong theoretical evidence" -- just like tachyons, another particle that hasn't been observed or conclusively ruled out.

      --Adam

      --
      "Invincibility is in oneself, vulnerability in the opponent." --Sun Tzu
  52. All suns are actually pockets of anti-matter by Anonymous Coward · · Score: 0

    That's right...they're just shells showing the boundary between the 'matter' and 'anti-matter' universes.

    Then, suddenly, OUR Sun starts spitting out what at first appear to be solar flares, but are really probes from the anti-matter galaxy within taking readings and exploring our planet and galaxy.

    MUAHAHHAHA

    And then the hero dies and...oh wait, that's some other book review giving away the ending. :p

  53. DO YOU UNDERSTAND ANTIMATTER AT ALL? by Anonymous Coward · · Score: 0
    consider an atom. It has a positive-charged nucleus (composed of neutrons and protons), and orbitting electrons (with a negative charge).


    antimatter isn't magic, it's just opposite - a negative chanrged nucleus with positrons orbitting about it.


    a brief consideration of these 2 facts should make it obvious that if matter can form compounds and aggregate, then antimatter can do the same.

  54. There is ONE way to tell! by Doesn't_Comment_Code · · Score: 1

    "First of all, there's basically no difference between a galaxy (or a physical body) made of matter and antimatter... Actually you wouldn't be able to tell." You may be familiar with the "right hand rule" which defines the direction of many physical interactions that are mathematically described by a cross-product. Antiparticles should behave oppositely, following an anti-right hand rule. A favorite quote from my professor at Drake. "If you go to shake hands with an alien and he reaches out with his left, DON'T TOUCH HIM! ... He's antimatter."

    --

    Slashdot Syndrome: the sudden, extreme urge to correct someone in order to validate one's self.
  55. Re:WTF? Do your own research! And protect yourself by sander · · Score: 1

    for what reason do you conisder it to be? count the number of clueless and irrelevant answer to the original post and look at the ratio to ones that aren't - doesn't look like a resource you'd want to use.

  56. anti-blackholes? by JDizzy · · Score: 1

    I wonder what would happen if a anti-blackhole collided with a normal blackhole. Would they eat eachother up instantly, or blow up? Would the bigger blackhole simply become that much less massive? Or what about dark-matter coming in contact with anti-matter, is that even possible?

    --
    It isn't a lie if you belive it.
    1. Re:anti-blackholes? by multiplexo · · Score: 1

      If you were to take a large chunk of anti-matter and compress it to the point where it became a black hole it would be indistinguishable from a black hole made out of positive matter. The only information you can get from a black hole is it's mass, rotation and electrical charge, every other bit of information about the particles that go into it is destroyed (which gets you into some interesting speculations on black hole entropy that I don't even understand). This is known as the "Black Hole No Hair Theorem". If you were to take two black holes, one of them the aforementioned anti-matter black hole (which is a contradiction in terms because once you've created the black hole you've lost all of the information about what made it) and the positive matter black hole and run them into each other you would end up with a bigger black hole.
      Kip Thorne's book on Black holes Black Holes and Time Warps: Einstein's Outrageous Legacy is a good place to start if you want to learn everything about black holes you can learn without having to be as smart as Thorne or Stephen Hawking. Timothy Ferris'sbooks The Whole Shebang: A State of the Universe Report" and Coming of Age in the Milky Way also have some good stuff on black holes.
      Now, since dropping two black holes into each other isn't going to do anything more interesting than creating a bigger black hole (which is interesting in and of itself but is not particularly spectacular in an explosive sort of way what you want to do is take two neutron stars, one made of neutrons and the other made of anti-neutrons and run them into each other. That would provide a rather impressive explosion, or you could take a neutron star and pile matter on top of it until it's gravitational attraction is greater than the degeneracy pressure. At this point, according to theory, a black hole will be formed and a huge amount of energy will be released as the neutron star collapses into the black hole.

      --
      cheap labor conservatives - they want to keep you hungry enough to be thankful for minimum wage.
  57. Re:DUMBASS! Where do you think Dark Jedi come from by Lester67 · · Score: 1

    How do I mod you unfunny?

  58. Not to burst your bubble but... by gatkinso · · Score: 1

    ... it has been thought of before.

    OK, I admit it... I WANTED to burst your bubble! ;-)

    http://livefromcern.web.cern.ch/livefromcern/ant im atter/everyday/AM-everyday03.html

    --
    I am very small, utmostly microscopic.
  59. Re:DUMBASS! Where do you think Dark Jedi come from by Valdrax · · Score: 1

    If you did, you'd already know that the dark side of the force is fueled by "every living thing made of anti-matter."

    I'm sorry... don't you mean "anti-midichlorians?"

    --
    If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
  60. Why we can safely say there are no antistars by chadamir · · Score: 1

    We know that there aren't antimatter stars because we'd be seeing huge antimatter and matter phase out reactions. If an antistar hit a regular start the energy released would be amazingly huge. Thus we can safely 1580that this is not happening.

  61. After by Eevee · · Score: 1

    Nothing like losing your air supply to get your attention.

  62. Annihilation, Jim. by squashed · · Score: 1

    Spock continued, "Annihilation, Jim. Total, complete, absolute annihilation." "Of everything, everywhere." Kirk clenched his jaw.

  63. Re: "thin boundary layers" by j_presper_eckert · · Score: 1

    If you want to spice up your story, postulate that these boundaries are *extremely* thin. Then go to your library and look up the physics of the "Leidenfrost layer". As originally researched, this has nothing to do with antimatter physics, but it presents an interesting what-if on how masses of M and A-M might exist in very close proximity in a semi-stable configuation. The big question is how long such a configuration can last. This allows for some dramatic tension in your story...especially if we're talking about galactic masses of M and A-M.

    --
    Can't stop the Beta? Time to evacuate to ##altslashdot at webchat.freenode.net - Slashcott in effect.
  64. There should be some way to figure it out by wayne606 · · Score: 1

    I'm not up on the physics, but I think that the fact that our universe is made of mostly matter implies that there must have been some asymmetry in the early period after the big bang. This has been discovered: see
    http://www.slac.stanford.edu/slac/media-info/ 20020 723/sine2b.html

    So maybe if you looked hard enough at the light from an anti-galaxy you could tell the difference - some miniscule difference in the emission spectrum or something.

  65. Antiparticles by Mark_MF-WN · · Score: 1

    If I'm not mistaken, only particles with mass can have an "anti" version. It may even be only particles with charge, but I wouldn't swear to it.

  66. Blackholes and anti-blackholes by Radical+Rad · · Score: 1

    Your story has got me thinking. It is suspected that gamma ray bursts may be caused by the merger of two blackholes. A large gamma ray burst is so energetic that it can emit more energy for a few milliseconds than every other radiant object in the universe combined. But what would happen if a blackhole merged with an anti-blackhole? There would still be the huge outpouring of energy because this is evidently due to effects manifested outside the event horizon. However, what happens after the matter and the anti-matter come into contact inside the event horizon? Normally the two opposing forms of matter would annihilate each other and become pure energy. But energy does not possess the property of mass, so could two equal sized holes wink out of existence in a bigbang-like explosion?

    1. Re:Blackholes and anti-blackholes by rjh · · Score: 1

      Warning: my physics is several years out of date. That said... every singularity is its own antisingularity. That is to say, you cannot tell a difference between a black hole formed by conventional matter collapse and a black hole formed by antimatter collapse.

      If a matter singularity and an antimatter singularity collided, we don't know what would happen. For all we know, mutant space hamsters fly out of their nether orifices. It all happens inside the event horizon; we can't see it, can't experience it, it's totally forbidden from interacting with us in any way.

      On the other hand, conservation of mass-energy is upheld. So even if all the mass gets transformed into energy (highly speculative, since we can't know what happens!), that energy will forever be contained within the event horizon; the Einsteinian geodesics all loop back upon themselves. So you've got a huge energy discharge traveling forever within a very narrow, confined space.

      It's not just mass which distorts space-time and creates the appearance of gravity. Energy can do the exact same thing. So if the entire mass gets converted into a singularity--there's no big deal; it's still a black hole by virtue of how much energy is compressed into that space.

      Again: my physics is several years out of date, and this is all IIRC.

    2. Re:Blackholes and anti-blackholes by Radical+Rad · · Score: 2, Insightful
      you cannot tell a difference between a black hole formed by conventional matter collapse and a black hole formed by antimatter collapse.

      I was about to argue this point but I just read it again slowly and see now that it is technically correct. You can't tell the difference from the outside. However just because some form of matter passes that point which we call the event horizon doesn't mean that anything magical happens to it. I read just recently that someone, Hawking I think, proved that if you fell into a blackhole you couldn't tell when you had passed the event horizon. So just because you couldn't tell from the outside whether a blackhole is matter or anti-matter doesn't mean that there couldn't be a difference. But maybe there isn't. Maybe it all gets squeezed into a quark soup.

      It's not just mass which distorts space-time and creates the appearance of gravity. Energy can do the exact same thing.

      Okay this is news to me. I would like to see references for this. It has been a few years for me as well but I was taught that energy, such as a light beam, will follow the space time curvature, but does not by itself cause any curvature. If you know the name of the governing equation that relates gravitational force to electromagnetic energy density please tell me because I would be fascinated to read about it.

      Just to be sure I understand you right; In a hypothetical universe with only two particles forever orbiting each other, if a beam of light suddenly shone between them then they would slowly approach each other in a tighter orbit until finally they touched? Is this right? Although this makes intuitive sense I am pretty sure it contradicts what I have always been told.

    3. Re:Blackholes and anti-blackholes by rjh · · Score: 1

      I would like to see references for this.

      Einstein's General Theory of Relativity. The Special Theory only relates mass with spacetime distortion; the General Theory has the mass-energy equivalence.

      If you know the name of the governing equation that relates gravitational force to electromagnetic energy density please tell me because I would be fascinated to read about it.

      E = mc**2. Or, E / c**2 = m.

      Or, g = (E1/c**2)*(E2/c**2) / d**2.

      Googling for "energy distorts spacetime" returns a couple of references. Try http://blueox.uoregon.edu/~karen/astro123/lectures /lec08.html for starters.

      http://www.exodusproject.com/GravWave.htm

      also quotes the famous GR maxim, "Mass-energy tells spacetime how to curve; spacetime tells mass-energy how to move."

      There is no difference between mass and energy from a relativity perspective.

  67. Re:WTF? Do your own research! And protect yourself by Atzanteol · · Score: 1
    for what reason do you conisder it to be? count the number of clueless and irrelevant answer to the original post and look at the ratio to ones that aren't - doesn't look like a resource you'd want to use.
    You say this knowing what the responses are. 20/20 hindsight and all. But even a few good responses may be worth the relatively little effort of posting the question to /. Free feedback, and all the questioner has to do is sort out the good from the useless (like our conversation).

    I still can't understand how whining like yours gets modded up as an "insightful" answer to a question... Why are you responding with a non-answer? Just like to hear/see yourself whine and bitch? You must be a hoot at parties...
    --
    "Ignorance more frequently begets confidence than does knowledge"

    - Charles Darwin
  68. Could work though, if... by tjstork · · Score: 1


    If instead of one big bang, in this universe, there were several, 100 billion light years apart. The universes would each cease to exist before they could detect each other...

    --
    This is my sig.
  69. Penile Implants? by Anonymous Coward · · Score: 0

    Can you please email me some information on how to get a bigger penis? I never seem to get any information on this terribly important topic.

  70. Very dangerous... by DonVictor · · Score: 1

    You would be killed by a massive burst of croutons.

  71. why only 3d by Lost+Penguin · · Score: 0

    Why only think in 3D, why only lightyears away?
    There are very valid arguments for more that 4D space(high, deep, wide, time)
    Just because we only perceive 4 dimensions, does not mean there are no other unseen dimensions.
    (this would explain "curved space" and wormholes better)

    --
    I am the unwilling control for my Origin.
  72. well... by VanillaCoke420 · · Score: 1

    It doesn't matter! Or in other words: antimatter.

  73. Anti-matter Star by The+Shootist · · Score: 1

    Larry Niven already wrote a story about an anti-matter Star.

    "Flatlander, by L. Niven (in the short story collection " Neutron Star", 1967). Astronauts investigate an antimatter object at the very edge of known space, with a lot of real physics throw in "

  74. Re:WTF? Do your own research! And protect yourself by sander · · Score: 1

    20/20 hindsight? get real - the ratio is more or less the same on most of ask slashdot. It might serve as a resource from which you pick up things
    to reserch, but it is not on itself a credible source.