Does time go back before the Big Bang?

[Martin]

It's an exciting question and getting increased attention these days. I'll get some links later to current research. For clarity, what I mean by Big Bang here is simply the beginning of expansion, not any one version. There are lots of different scenarios---all I mean is the generic start to the process of distances increasing that we see going on (possibly including a brief episode of inflation).

 

Many people have views they favor on this issues. Let's discuss our favorite ideas and hunches freely in posts. The poll, however, is about something else. It is intended to help establish what is known. Is there any scientific reason to believe that time started some 13.7 billion years ago? Is there, on the other hand, any empirical evidence that it did not?

[Kyrisch]

More and more scientists are recognising time as comparable, even identical to space property-wise. Since the evidence points to the structure of space expanding in the three dimensions we know starting at the Big Bang, why should the inception of time be anytime else?

 

My favourite version is that our visible universe is a 3-brane with a relative velocity to the universe in the time-like direction of c.

 

[Of course this is all my take based on my limited exploration of theoretical modern physics.]

[SamWalker]

You must be an idiot to ask such a dumb question. There are even more stupid people trying to answer.

[mooeypoo]

You must be an idiot to ask such a dumb question. There are even more stupid people trying to answer.

 

How, exactly, is this helpful to the debate?

[jjuris]

As much as 13.7 billion seems like a very large number, it is very limiting. This would be more philosophy than science, but could we actually believe that there was an absolute set beginning to existence. This is the struggle that contains us. There is no way to know. Did time begin at the Big Bang. M Theory tells us no. Like with anything there is yes and no. Up and down. Matter and antimatter. Time moves forward and can move back, but there has to be an order, a harmony.

[Realitycheck]

Since the evidence points to the structure of space expanding in the three dimensions we know starting at the Big Bang, why should the inception of time be anytime else?

 

Primarily because of hypothetical ideas such as a Big Bounce, where the universe has expanded to its limit and contracted to a Big Crunch at least once before the Big Bang as we know it.

[foodchain]

You must be an idiot to ask such a dumb question. There are even more stupid people trying to answer.

 

you sir are an asshole.

[YT2095]

I vote that we just don`t know yet, but personally I think there was no time as such, as Time requires Change to measure and if there`s Nothing there to change or measure, there`s no Time.

[Royston]

you sir are an asshole.

 

Well said.

 

I voted 'we don't know yet'...because we don't. Whatever models have been derived for pre big-bang scenarios need to be tested...that's when the evidence comes into play.

 

The problem is probing such high energies, which are not reproducible in a lab, we may get close to an answer via GRB's et.c Or there may be a model that predicts current observations better than existing models, which includes pre big bang periods.

 

However evidence wins, and personally I'm unsure we'll ever know, when such things are not falsifiable by direct measurement / observation. Which is a tad tricky where this problem is concerned...unless anybody knows of other methods.

[john5746]

To me, time as we know it must have a certain direction, a forward arrow. If it is curled up with no direction, it can be ignored as non-existent.

 

I am under the impression that time doesn't exist at the quantum level, doesn't exist at c and doesn't exist with extreme gravity(i.e blackhole). So if the universe was compacted to the quantum level at some point, tough for me to imagine anything like time at that point.

[Martin]

So if the universe was compacted to the quantum level at some point, tough for me to imagine anything like time at that point.

 

It might help to see some of the results of computer models based on quantum gravity. They run smoothly through that point. They have produced 3d plots of the quantum wave function (of a variable connected to size or density) evolving thru a bounce, with continuous time-evolution.

 

The point is not to claim this or that is right. Nonsingular cosmology (that doesn't blow up at the big bang) is being studied a lot recently. If you find it tough to imagine then one thing that could help you imagine is to look at some of the computer graphic output from these nonsingular models.

 

If you want, let me know, and I will get some links.

 

I should repeat so it's clear: I'm not saying one thing or the other thing is right. I am saying you now have equally good models that don't break down, and that fit the data equally well. So there is no scientific reason to make an assertion one way or the other. It is undecided.

The nonsingular models will in the future be testable however, because they make slightly different predictions about what happens in the early universe, around bang time. Some of the current research is aimed at translating those into visible effects that we can look for in the Cosmic Microwave Background. Testing the nonsingular (bounce) cosmology models will take time, and it will require better instruments---like the Planck spacecraft scheduled for launch in 2009---but it's pretty clearly in the works and we can expect it to happen.

Edited October 23, 2008 by Martin

[john5746]

If you want, let me know, and I will get some links.

 

 

Yes, I would appreciate that. Not sure if my pea brain will comprehend, but would like to try.

 

I found the loop quantum gravity theory in Einstein Online appealing. It makes more sense than just a singularity. Doesn't make it right, just more interesting.

[redsaint63]

if you think the big bang was the start you are so wrong... something made contact with the finite point to cause the sudden release of life sustaining particles. if you think of it as if you were just born and nobody told you anything about reproduction you just base your theories about where and what you came from(mom) and never meet dad so you think life comes from mom. when it takes two to make life here on earth. why couldn't that be viable in the universe???????????????????????????

[Realitycheck]

There is no evidence whatsoever that there was time before the Big Bang, so it is all simply speculation.

[Martin]

At the top of each forum Dave has a "Notice to All Posting Here" which is worth noticing

http://www.scienceforums.net/forum/announcement.php?f=15&a=12

 

The relevant portion here is:

Please note that all posts that are baseless in scientific fact ... can and will be moved to the Speculations forum.

 

In other words, if you claim to know something without there being scientific evidence for it, that qualifies as speculation.

 

Personally I don't think it's necessary that every groundless assertion be moved to Spec forum. Unsubstantiated claims are often self-discrediting and apt to backfire on the individual making them---doing no harm. And I tend not to take issue with qualified (IMO, tentative, obvious subjective judgment) statements. It is mostly just flat declarations, as if a fact was being stated, that seem like egregious speculation---everybody has their own tolerance level about this, I imagine.

 

==============================

 

To give an example: to flatly assert that time started with the big bang is speculative.

Because there is no scientific evidence that it did. There are some models in which time did start there (because the model breaks down and doesn't work at that point) and there are some in which time did not start there. So far both sorts of models fit the data. More precise observations will be needed to discriminate between models and decide which passes the test.

 

Therefore one cannot rationally conclude that time started with the big bang. To claim to know that it did start there is speculation.

 

The non-speculative statement is that we do not know whether it did or not.

==============================

 

BTW thanks to all who have posted so far. Several posts definitely interesting, and at least a couple were thoroughly entertaining!

Edited October 23, 2008 by Martin

[mooeypoo]

Yeah, this thread is walking the thin line of speculation.

 

By the way, I resent the implication that moving a thread to the speculation forum is a "bad" thing or a "punishment", and is raised as a supposed "threat".

 

Speculations can be quite excellent and very much contributing to our scientific thought, but they need to be based, at least in their 'base' in evidence.

 

There's nothing wrong with speculations, as long as they are characterized as such.. if the thread 'moves to speculation' it just means that it's not a mainstream proven astronomical points that are raised, but rather speculative.

 

I don't think people should treat this as a "threat".

 

It is what it is, and we're having a discussion on subjects that (as Martin pointed out) are not yet known.

[Realitycheck]

Just putting my money on the conservative line.

[npts2020]

Well, cosmology (and much cutting edge science as well) is by its nature speculative and imo impossible to discuss without some resort to speculation. Personally I know so little about time that I haven't decided whether it is an intrinsic property of the universe or a completely artificial human construct or even if one or the other matters. However, with my meager knowledge of the subject, I would speculate that time extends well beyond human perception, seemingly infinite, but not so in fact. How's that for waffling?

 

 

 

SamWalker: Run along now. Don't forget your pitchfork and torch on the way out.

[Mr Skeptic]

I think that time did not start at the Big Bang. Perhaps our time started at the BB, but some theories like the Big Bounce allow our time to extend before the BB. In any case, if cause and effect still holds before the BB, then there had to be an order of events, which would be a form of time.

[interstellar]

If you could have lived before the big bang, it would probably be like sleeping nothing everywhere and blackness in all directions.

[Bettina]

I think that time did not start at the Big Bang. Perhaps our time started at the BB, but some theories like the Big Bounce allow our time to extend before the BB. In any case, if cause and effect still holds before the BB, then there had to be an order of events, which would be a form of time.

 

My sentiments exactly.

 

Bettina

[Martin]

You know it actually is kind of an intriguing question, what (according to the various models that go back before) would it be like if you were living and observing things before the so-called bang.

 

I mean, if you pick one of the models that does NOT break down right there (the way vintage 1915 General Relativity does) and continues back a ways, and if you use that model to reconstruct---then imagine how things would look and what would be happening around you.

 

The actual moment of bounce would be hell of course (in the bounce model), but if you go back long enough before that, how would it look? One could think about that. Plenty has been published about this, computer modeling with various assumptions, in general the results are fairly symmetric, like running a big bang backwards. The stuff that has been published plots physical parameters, however, without visualizing. If you visualize you may get a more vivid sense of what's going on.

 

Like some 380,000 years before the bounce the CMB (cosmic microwave background) has heated up to around 3000 kelvin and stuff is beginning to ionize----so that's not so hospitable. Maybe one's imagination wants to go back 4 or 5 million years before bounce, before the big heat wave. I don't know, so far I didn't ever take that thought trip.

Edited November 11, 2008 by Martin
multiple post merged

[pioneer]

The estimate of 13.7 billions has an arbitrary t=0. Say the first event, we call t=0, actually lingered for 10 billion years before it began to expand, this would all be lumped as 0 seconds. We started the stop watch when the expansion began, but that does not mean the universe clock just appeared when we start the earth clock. That assumption is used to set the clock at 0. The universe clock could already be at t=X but we call it 0, by human convention.

[aguy2]

in re: t=0?

 

The estimate of 13.7 billions has an arbitrary t=0. Say the first event, we call t=0, actually lingered for 10 billion years before it began to expand, this would all be lumped as 0 seconds. We started the stop watch when the expansion began, but that does not mean the universe clock just appeared when we start the earth clock. That assumption is used to set the clock at 0. The universe clock could already be at t=X but we call it 0, by human convention.

 

Are there other sound reasons, other than human convention, to presume that at the BB t had to equal 0?

 

Semanticly at least, it seems to make sense to me that at its inception (the BB), "The universe would have had all the time it will ever have.", thus t=1.

 

If t=1 at the BB and s=0, might not time/space be seen as 'equivalent' in that their sum is a constant?

 

I tend to look at reality (our universe) more from a philsophical POV, but why is 'time' seen in physics as the 4th dimension? Is this just because it was the 4th dimension to be considered? There seems to be a reasonable possibility that the BB developed from a 0 dimension singularity. If a 0 dimension precursor state changes into a multi-dimensionsl state, wouldn't the arrow of time (change) be the 1st dimension and not the 4th?

aguy2

[pioneer]

One of the arguments that got people away from the BB theory was the GR or gravity should have been too high for an expansion. This would be like expecting the biggest black holes to expand. This argument opened the door to other scenarios in spite universe expansion data. Another way to look at it, the same argument implies lingering until it finally is able to somehow reverse. Say is it pulsating in and out of singularity, erratically. We would have sort of a discontinuous ticking of the clock, with these ticks heading to the future probability one key pulse will open up space-time for good.

 

At the singularity state there is no time. If there are any odds, a vibration can occur since time is not a factor. Using simple probability, small pulses are more likely than the huge BB pulse. So we might expect a lingering-vibration until the lower odds for full expansion finally get satisfied. It is not clear how much all the ticks in the scenario, add to.