Is it possible that in the begging of time tachyons could be responsible for the big bang. The way I am thinking about it is if tachyons existed at the begging of time and they traveled back in time where as everything else went forward there would be an imbalance of energy maybe creating an imbalanced singularity which erupted into the big bang.
Tachyons? Bugger the beggars.
Since Physics As We Know It doesn’t apply at the moment of the Big Bang, and since Tachyons are still completely theoretical particles, I’d say that there’s no way to know.
Doubtless a SDMB physicist will be by soon to clarify.
Run some numbers, and let’s check it out.
Well, one quick and dirty flaw, even ignoring the “do tachyons exist” issue is that, well, it’s not possible to go backwards in time beyond where time started. So you couldn’t create a bunch of tachyons at the moment of the Big Bang and then send them whizzing off backwards through time because at that point, there WAS no backwards in time.
how do you know that. and if that was true does that mean that if tachyons existed after the creation of the universe does that mean they would go to the beginning of time and then not ceace to exist. I thought time is something we made up so how can you say you can’t go back before it???
It’s possible to conceive of “a temperature below absolute zero” – but there’s no physical way to achieve it. There’s nothing north of the North Pole because “north” is so defined that the farthest north you can go on the surface of the earth is the North Pole, and beyond it is not “north” but “up” or else “south.”
Time and space began with the Big Bang (presuming a Big Bang cosmology) because it took the interaction of matter and energy to create them. “Time” is meaningless when there is nothing to measure – even visualizing yourself in an otherwise empty cosmos, you’ve injected yourself and your own sense of duration into it.
Hence time (and space) came into existence with the Big Bang, and there is no time before it.
I believe it was Isaac Asimov who wrote an essay speculating that at the moment of the Big Bang two universes were created: ours, and a counterbalancing universe of negative mass and energy that ran backwards in time. His point in supposing this was to suggest that since the two universes together had zero net mass and energy, it might explain how something could have come out of nothing. I presume that current cosmology theories get around this in other ways, but it’s still a cute idea.
Current cosmology gets around the “how does something come from nothing” basically by noting that gravitational attractions are negative in energy… in essence, the idea is that “something” is matter plus gravitational energy, and that “something” happens to add up to nothing, as it were; the net energy of the universe is zero. I don’t claim to be able to prove this.
As for how I know that time started with the Big Bang, I don’t, of course. If I believe in the Big Bang (and I do), then Polycarp is quite correct. If I don’t believe in the Big Bang, then I really can’t address your question at all, because I’ve just stepped out of the realm of standard physics to begin with. I could speculate freely, but I wouldn’t be able to give anything other than a “well, it would be neat if” kind of answer, which I didn’t think is what you were after.
If all the matter in the universe were compressed into a volume of space no bigger than an atom, how then would any amount of matter or energy escape the immense gravity from such a massive particle?
No amount of matter or energy would or did escape. Space itself expanded and all the matter and energy remained contained within its now larger volume.
Tachyons are soo yesterday. 
Perhaps you would have better luck incorporating Superbradyons which would possibly eliminate some of those intractable problems that tachyons present.
Superluminal Particles in Cosmic-Ray Physics (PDF file)
emphasis mine
I still dont understand…
So, space expanded, why then would the matter expand? Its mass was considerably greater than the mass required to form a black hole. So after space expanded, matter should have stayed right where it was, and formed a black hole.
It’s a variation of Gertrude Stein’s “There’s no ‘there’ there.” The “where it was” was the entire universe so as the universe expanded so did the “where”. Keep in mind that the universe has no boundary, there is no place for the matter to “move into”. It is already there. A black hole has a surface. The universe doesn’t.
It’s a variation of Gertrude Stein’s “There’s no ‘there’ there.”
So what you are saying is that space and matter are intrensically linked to the universe. The universe expanded, hence space became greater in volume, and the matter that was in the space expanded as well, just not as fast. Kind of like the surface on a balloon.
So at what point in time did Einsteinian physics become dominant? Very quickly after the universe was made, or did it take many millenia?
I do not think there can be an anti-universe running backwards in tipe because not all matter obeys T symmetry… kaon decay violates it, I believe? I’m trying to toss a bone in here for someone who knows to snatch it up, because I think kaon decay and symmetry was discussed before, but I can’t seem to find it… thanks if anyone knows.
Well, the decay of neutral kaons shows CP violation, but I’m not sure that T violation has been directly observed yet (my references on this are all 15 to 20 years old). Of course, we believe very strongly that there’s no combined CPT violation, and if the CPT theorem is true, then it’s also true that not all matter obeys time reversal symmetry.
Whether this has anything to do with tachyons causing the Big Bang is a bit outside my field, but my gut instinct is that it doesn’t. I couldn’t even begin to argue that point, though. I also don’t think you need such an argument to decide that tachyons were probably not the “cause” of the Big Bang.
And Ficer, GR took over gravitation (i.e. gravity became classical) very shortly after the Big Bang.
I should have indicated a hijack… I was responding to the Asimov post of Lumpy.
So we don’t know if it violates CPT? My understanding is that CPT is the supreme symmetry (I just mean: the one we really like), as you confirm, but I swear I remember hearing either a prediction of violation or a confirmation of it WRT kaon decay. I remember where I read this, I’ll check at home tonight to see what it says.
If gravity became “classical”, very shortly after the big bang, then all the matter in the universe should be moving away from a a central point in the universe, and all of the matter in the universe ought to be slowing down.
This is incorrect, however. Part of the effect of the BB is that space itself is expanding, which means all matter is moving away from all matter: any point might as well be the center of the universe, as from every point in space all other matter is receeding (more or less—I believe there are some minor variations here; at least, there are some blue-shifted electromagnetic radiation received from distant sources, but I don’t know if this is only WRT the average amount of red shift we see based on distance or what).