What was the Big Bang before it Banged?

Factual Questions
21

It is probably very pretentious of someone with no more math than I have to aspire to explain Stephen Hawking to anyone, let alone other straight dopers, but…

… as I understand it, in A Brief History of Time, Hawking starts talking about how gravity curves things. Light, for example. Light normally moves in a completely straight line, but put some sufficiently dense object nearby and the path of light distorts around it. Nowadays we know this to be factually true. Those Hubble photos of gravitational lensing of far-distant galaxies, for one example.

Hawking says time curves like that, too.

You know what the Big Bang is all about: big expanded universe now, go back in time you also are traveling to a more dense, less spread out universe. Go back 12-15 billion years and you reach singularity and nothing “is” before that. BUT that entire sense of “go back in time”, if I understand Hawking correctly, ignores time-bending in response to gravity, which as you approach (in reverse consecutive order) the singularity you also move towards truly spectacular density and gravitatonal concentration…

From the land of equations, looking at time the way one might look at the trajectory of light that happens to pass close to a dense gravitational field but ignorant of that, one is thinking in a linear fashion. But if time curves (or umm uncurves as the density declines as the universe expands) the linear model is a misrepresentation…

Instead of thinking of, let’s say, the time frame between 13.8 and 13.0 billiion years ago as being temporally the equivalent of the time that elapsed between 1.8 and 1.0 billion years ago, we should assume the passage of time was already bent at an angle, and within that time frame was exhibiting a curve. There’s no entity to interview and ask “what was it LIKE to experience that 0.8 billion years, compared to, you know, your average 0.8 billion that go by nowadays”, and math doesn’t readily lend itself to “here is what things woulda FELT LIKE”, but I think Hawking is saying that those years back then were LONGER. And the years between 14.0 and 13.8 billion years ago (give or take; I forget exactly how old we now believe the universe to be) were even longer years, the more so as you go back in time, until very very close to the singularity what you have is a sort of infinitely timeless pre-time… a primordial “before” in which time was curved entirely away from the orientation in which we know it, gradually giving way to both physical expansion and the increase of the rate of the PASSAGE of time.

Thus, were you to hop into your HG Wells time machine and try to “go back” and see the Big Bang “event”, the “Zero Seconds and Counting” moment when the singularity goes boom, you instead get real close to that and hop again and are only marginally closer and marginally farther back in measurable time.

22

What everything else is before it gets banged up.

23

eniplaand then a miracle happened.

24

It’s entirely possible – such a scenario is generally called a ‘Big Bounce’, and recent theoretical work by Martin Bojowald has renewed discussion on the subject, from a Loop Quantum Cosmology vantage point. Here’s an article (PDF) giving a summary of these developments that appears to be quite readable (I’ve only skimmed it so far).

I’m no expert, but I don’t think that particular notion features prominently in Twistor Theory, and even if it does, it’s certainly not exclusive to it, presuming you’re talking about something like the one-electron universe put forward by Wheeler and Feynman.

25

It seems to fly against reason that time would not exist but it could happen. I mean one would say “Just because I wasn’t around to see WWII doesn’t mean WWII didn’t happen.” So one could extend this by saying, just because we couldn’t measure time before the big bang doesn’t mean time didn’t exist.

This is a bit oversimplfied but look at it like this:

As you approach speeds of light time slows down. Eventually it will stop. So time isn’t going forward (as we know it does) nor is it going backward. It’s just stopping. It’s not like when we sleep and time doesn’t seem to exist, because time is actually moving forward. In this case time is actually stopping.

It’s not like we go to bed at 9pm and wake up at 6am and don’t notice the passage of time because we were unaware. It simply stops for EVERYTHING. There’s no outside observer.

26

That’s what you get for trying to be your own agent.

27

If you think you oversimplified, let me try to out do you and explain why time could not exist pre-Big Bang.

The only way to measure anything is relative to something. If I wanted to know how far it is from my house to a Taco Bell in Trenton, New Jersey, I could get out a map and measure the distance on a scale. If I wanted to know the outside temperature, I could see how much warmer the air was than freezing water and use that scale. If I wanted to know what time it is, I could look at the position of the sun, or the rate of atomic decay, and on and on.

Prior to the Big Bang, everything was one thing. The one thing was so small, it was nothing. Picture a point in the middle of nothing. The point is relative to nothing, so you can’t define it anywhere. The point has no speed or temperature, because there is no way to measure the speed or heat. There are no atoms to decay or sun to pass, so you cannot describe time in any real sense, because it did not exist.

I know this is hard for our three dimensional mind to wrap around, but you have to have two points to have anything that means anything. Pre Big Bang, we had even less.

SSG Schwartz

28

In the event, please do drop by. I think we have a Taco Bell somewhere.

What I want to know is why is it light, as opposed to something else whose speed/motion is so important? I mean, I understand that it couldn’t be The Speed of Eggplant, but why light as opposed to other kinds of energy? Or is there no other kind of energy and light is just the frequencies that we can detect with our eyes?

29

Please take all complaints to the Branch office. Or send them by Cabell. :stuck_out_tongue:

30

As Exapno Mapcase pointed out, this is properly attributed not to [the great] Gary Larson, but to the [also great] Sidney Harris.

I got my wife (who’s a research mathematician in Riemannian Geometry) this Sidney Harris cartoon on a T-shirt: the ultimate reduction of a Proof By Intimidation.

31

It’s got nothing to do with light as such, really. Rather, c is a fundamental constant of our universe, and happens to be the speed at which massless things move when they move unimpeded, such as light in a vacuum. In a medium, for instance, actual light moves slower than c (considerably so in some cases), but c itself is still the same constant.

Also, light is not really a ‘kind’ of energy any more than a thrown baseball is – both carry energy (though the baseball is different in that it also has a rest energy).

32

Thanks, Half Man.

33

I know a great deal about spatial and temporal relationships. That is what I do. I convert spatial and tabular data.

People still seem to believe that the ‘big bang’ just happened. And now— here we are.

WHERE did all the hydrogen and carbon come from?

34

Everything is composed of [del]molecules[/del] [del]atoms[/del] [del]subatomic particles[/del] umm, quantum states that have a tendency to exist.

The universe in its entirety is a rather large vacuum fluctuation. It just happened and here we are.

If you prefer a less happenstance explanation it came into existence because it wanted to. It’s here on purpose and we’re a participatory part of it.

35

Energy.

36

So time itself “slows down” the closer one is to the big bang until you reach the point at which time does not exist, right?

So what does it actually mean when scientists discuss the first fentoseconds after the Big Bang? Our time? Slowed down time?

My brain hurts.

37

If I’m understanding correctly, those femtoseconds may have lasted eons if you had some way of “straightening out the curvature”.

That’s a fairly large initial disclaimer. I’m waiting for someone more grounded in this stuff who read Hawking to come along and correct my interpretation, and I’m wondering how far off I am in my grasp of what he said.

38

Don’t worry about it. I’m pretty sure that not a word of what AHunter3 said in that post is correct, literally or metaphorically. Time always proceeds at one second per second to the local observer, even at the beginning of the universe.

39

Oh. Well, that explains it.

40

It was Everything. And it was Nothing.