I think we’ve a bit of clarification to do, Hammer.
I believe that the constant you’re thinking about is the density parameter; if it’s 1, the universe is flat, if it’s greater than 1, the universe is closed (there’s enough stuff to stop cosmic expansion), and if it’s less than 1, the universe is open. No one at present knows what the density paramer is, and estimates vary wildly. (Dark matter is a big problem here.)
The Hubble constant is a measure of how fast the universe is expanding; it tells us how quickly a galaxy at a given distance is receding from us. A convenient way to write it is that H ~ sqrt(1/2)100 km/(sMpc). The Hubble constant (which isn’t really constant, but let’s ignore that) has dimensions of 1/time, so it’s numerical value can’t be specified without including units.
AFAIK, the best current fit to the data is that the density parameter (the fraction of critical density in matter/radiation) is about 0.3, the fraction of critical density in the cosmological constant is about 0.7, and the fraction of critical density in curvature is 0.
In fact, Lee Smolin in his fabulous book, The Life of the Cosmos, opines that the Universe does evolve - into other universes. A new universe is created in the “centre” of black holes (a “bounce”) and this new region contains new laws of physics. The laws of physics in these regions may be especially favourable for the creation of even more universes etc.
Smolin is no crank. He is a professor of gravitational physics at Penn State, a leading general relativity center.
Back before Einstein came on the scene, scientists still believed in the “Ether”, a sort of spatial something-or-other that existed “behind” the universe… in other words, a universe for the universe to exist in. However, all the theories about the “Ether” were based on guessing, since its very nature made it impossible to be observed.
Then ol’ Albert came along and said, “Why do we even bother speculating about something that we can never observe?”
I feel much the same way about the OP’s possibility. Even if we were the second, third, fourth, ten trillionth, etc. universe, it wouldn’t matter… we’d never be able to make any observations about what came prior to the Big Bang. Everything else is just speculation, and can never be proven or unproven.
In other words… “Sure, we can be the second universe, if you like.”
There was this short short short story by Mike Resnick which dealt with that question. The story was 800 words long so I don’t think I’m spoiling anything by telling you about it. Basically, it talks how this guy has invented a drive to travel at the speed of light. He’s the 37th person ever to have created such a device.
He turns it on, gets it up to the speed of light and BAM! he realizes at that instant his mistake. He now has infinite mass and the rest of the universe comes rushing towards his infinite gravitational pull. The entire universe is wiped out in The Big Crunch…for the 37th time.
Jeez, Ender… are you sure that wasn’t the plot to an Outer Limits episode? Because I’m both laughing and creeped out by it at the same time… t’hell with worrying about nuclear weapons, we have to stop NASA from activating the FTL Drive!
Interesting SPOOFE. In another thread elsewhere on these boards, people are saying that it’s important to use the powers of deduction (speculation) in order to explain the causes of effects that we can see (not very well put). this is good science.
Example, we can’t see quarks but we can see their effect so we speculate (deduce) about what a quark is.
See what I mean… (bad pun)
pax
p.s.
I got all the way down to ** Gaudere’s** post wondering why everyone was so upset with the title (even wondering if I had lost the plot because it seemed like a good title for the question… to me at least.) Now I understand! :o
Omega is the symbol/term used for this parameter. Current inclinations are that the universe is flat (omega = 1) especially since the BOOMERanG results came in.
Oh, and thanks for the previous clarification - - yes, I agree.
[aside]
Ah, yes. I misspoke, Phobos (this is what I get for not being a relativist/cosmologist and not having any references handy but opening my big mouth anyway). Thank you for the correction.
What I should have said is that Omega[sub]m[/sub] appears to be about 0.3 with Omega[sub]Lambda[/sub] = 0.7 and hence Omega = 1, a flat universe, but that estimates of Omega[sub]m[/sub] vary. I think most people agree that Omega = 1, but how that’s partitioned between matter and the cosmological constant is poorly constrained by the available data (if I understood the papers correctly; I could barely read the crappy pdf).
[/aside] Spoofe, the reason I care is not that it matters to me whether the first or the 10 thousandth universe; that’s immaterial, because as you rightly said, we can never know anyway. But if scientists are right, then knowing something about how our universe started and whether there were other universes before it would tell us a bit about how our universe will end and what happens “after.” This won’t have any great impact on my life, of course, but to me, these things are worth knowing.
Also it may give us more clues about how the very “fabric” of the universe works.
If I read you correctly, you’re primarily interested out of curiosity, which is NOT a bad trait (despite what they say about the cat). But now that I’ve spent a little time thinking about it, there may be actual benefits to such a discovery. Perhaps there are aspects of “creation” that aren’t directly related to matter/energy?
My apologies if I seemed rude in my first post. 'Twas not my intention.
Yup. I could be wrong, and I have no cite, but I’d guess that this is what motives most scientists. Some are surely motivated by wanting to fix some specific problem (cure for cancer, anyone?), and a few are doubtless motivated by a desire for fame or by greed or some such, but as a whole, I think I’m right in saying that the main motivation of research scientists is curiousity. And as you note, this is not a bad thing.
shrug Beats the heck out of me. There may indeed be practical applications for all of this, but if there are, they’re probably decades away yet, and I have no idea what they would be.
No, not at all. To be brutally honest about it, there isn’t a whole lot going on in physics at extreme scales (i.e. general relativity, particle physics, etc) that has much practical importance. Since this is so, I suspect that a majority of people would toss up their hands and wonder why we bother doing the research to begin with. There’s nothing unreasonable about that, and I can sympathize with that point of view entirely; being a scientist often requires a rather strange mentality.
I think a related question would be, why are we so sure that there was a big bang at all? The universe is expanding (or it looks that way from where we sit) so we deduce that it all must have existed at one point at one time, i.e., big bang.
Sounds logical, but two things bother me: One is that entropy gets thrown out the window. Why would all the matter in the universe want to be at the same point? Matter wants to be at the lowest possible state of energy, but assuming it must have started at the highest possible state is circular logic.
Second, is it possible that our deduction is wrong in the first place? We only have one point of reference. Isn’t it possible that the universe isn’t necessarily expanding from a central point, but is just moving around in space? ( I have heard the mantra “there is no center to the universe” many times. doesn’t that contradict the idea of a big bang?) If we can’t determine where the point of origin was relative to ourselves, how do we know there ever was one?
BTW, Steve Wright, if you study linguists, doesn’t that make you an Anthropologist? And I bet there are some more exciting tribes out there to study, IMHO.
Gravity. It’s such a compelling force. I mean, even when I’m ten miles up, it can convince me to come plummeting to my death.
Of course it is. But so far, a lot of evidence suggests that everything originated from a single point. New evidence, when it is acquired, is scrutinized, and the theory altered to include the new evidence.
Very much so, that’s possible. In fact, it has occurred to me, as well. However, by examining the redshift of other bodies in space, we can pretty much see that everything’s moving away from everything else… which indicates a very powerful source of uniform momentum.
I dunno. I don’t think “there is no center to the universe” is officially a part of the Big Bang theory, and is just a saying that makes it way around certain circles.
First, understand that I took exactly as much physics as was necessary to graduate, then ran , screaming, back to the biology department. So thanks for indulging my ignorance.
I guess I get confused by the implications of Hubble’s principle. If the big bang was basically a huge explosion, then everything would be moving out from an epicenter. Assuming we are not at the epicenter, why would Hubble’s principle apply in all directions? Looking “forward” (away from the epicenter) it makes sense, but looking back across the epicenter, shouldn’t there be a point where the red shift increases dramatically? The matter thrown out in the same direction as us would appear to be moving away, but slowly. Once you looked past the epicenter, the combined velocities would make for a dramatic red shift, wouldn’t it?
Also, objects travelling along an eliptical path would appear to be moving away from each other. Planets orbit within solar systems, solar systems orbit within galaxies, why not galaxies within the universe?
That makes sense if you assume that we are in a crunch/bang/crunch/bang system. But if this is the first and only, how do you account for it (without getting metaphysical)?
(sorry about redirecting this thread, but we havn’t heard from the OP in a couple of days, and I was ruminating along the same lines anyway)
The problem, kindablue, is that the big bang wasn’t a huge explosion, it was a uniform expansion of space. The old balloon analogy sort of works here. Picture space as being the surface of a balloon. As you inflate the thing, every point on the balloon gets farther apart. That’s sort of like what happened with the big bang. Thus, the saying that there is no center to the universe is basically a way of remembering that there wasn’t an explosion of matter from one point so that matter started to fill space up, but rather an “explosion” of space itself. It’s not a contradiction of the big bang.
The reasons we believe the big bang are that (a) it provides a convenient explanation for a variety of observed phenomena, and (b) we believe general relativity, which predicts that the universe must be either expanding or contracting.
As for entropy, I don’t really see any problems. If the universe was a little tiny bit of space, and now it’s big with random clumps of matter (galaxies, stars, etc) and radiation, entropy has gone up, right?
(bad pun)