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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?"
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!
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.
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Here be Dragons
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).
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.
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.
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.
Could be fun designing a starship to cross this boudry.
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
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