What does 'Nothing' mean to a quantum physicist?

[pctopgs]

What does 'Nothing' mean to a quantum physicist? I was talking to a YEC about the singularity and he pointed me to a few cosmologist(Is this topic in the right place?) who said the big bang came from nothing. So my question are:

1) Is 'nothing' jargon used by cosmologists which have a totally different meaning from everyday usage?

OR

2) Does 'nothing' mean the same as the everyday useage 'nothing'? If so then can I have a really long but simple reason (Analogies, images, whatever to get the idea across) as to why this is?

Thanks

 

[mate0]

as far as i know there is only one meaning for the word nothing. no one knows what was around before the big bang, because the current laws of physics were created then, so it is impossible to determine what was before that.
there are many different theories about what was here before the big bang (some of them quite ridiculous), but i wouldn't say that "we don't know" is the same as nothing.

 

[Fredrik]

Even before I looked up "YEC", I was thinking that only a creationist would say that the big bang came from nothing. It's not a technical term. It's just something that ignorant and dishonest people say when they want to discredit a theory they don't understand.

So what does the big bang theory actually say? The question isn't really easy to answer, because there isn't just one big bang theory. The original big bang theory is the claim that our universe can be described by a solution of Einstein's equation with an initial singularity. Such a solution describes a spacetime in which every event has a time coordinate t>0. There's no t=0 and no t<0. The "big bang" isn't an event in this spacetime. It's just a name for the mathematical limit t→0.

So if we're talking about the original big bang theory, questions about what happened before, or even at the time of, the big bang, doesn't make sense, because they're asking us to accept as a premise that the theory we're supposed to use to answer the questions is logically inconsistent. The question "Did nothing exist at t=0?" is of that sort, so it can't be answered by that theory, or even asked in a way that makes sense, as long as we're supposed to use that theory to answer it.

If you're thinking "OK, so the theory doesn't say anything t=0 or t<0, but something must have happened before that", you're actually making a pretty naive mistake. (Don't worry, we were all that naive at first). The mistake is to assume that our intuition about space and time is more accurate than one of the two most accurate theories in the history of science, even though many of those intuitive ideas have been thoroughly disproved by experiments. (I'm talking about experiments that prove that general relativity makes better predictions about results of experiments than all of the theories that describe space and time in a way that's consistent with our intuitive ideas about space and time).

There are however models in which "the big bang" is something different than the t→0 limit. Those are all more complicated than the original theory, and I don't know any of them really well, but I can assure you that none of them asserts that something came from nothing.

 

[pctopgs]

Even before I looked up "YEC", I was thinking that only a creationist would say that the big bang came from nothing. It's not a technical term. It's just something that ignorant and dishonest people say when they want to discredit a theory they don't understand.

But that's the scary part: It seems that I can't shake him. He showed me a quote of Vilenkin where he said the universe came from nothing, and to my spine crushing surprise, the quote wasn't taken out of context (Or maybe I'm missing something). I looked up talk origins, and it said : "the "nothing" refers not to an empty vacuum spacetime, but rather to a quantum state of the universe in which "space" and "time" have no well-defined meaning (being only approximate, classical concepts)."

but I don't want to use this as a source in my rebuttal because the YEC can accuse it of being bias...I For the first time, I don't know what to do...

 

[pallidin]

There are however models in which "the big bang" is something different than the t→0 limit. Those are all more complicated than the original theory, and I don't know any of them really well, but I can assure you that none of them asserts that something came from nothing.

Nice, and I believe you are correct. You do realize your response statement opens up a can of worms. I love it !

 

[Fredrik]

But that's the scary part: It seems that I can't shake him.

A lot of people don't think rationally at all. They just decide what to believe first, and then interpret everything as evidence supporting their view. I agree that it's quite scary. It gets really bizarre when you thoroughly disprove their arguments and they counter by saying that you just believe what you want to believe.

He showed me a quote of Vilenkin where he said the universe came from nothing, and to my spine crushing surprise, the quote wasn't taken out of context

Physicists are often sloppy when they try to explain things without mathematics, and the results are often misleading.

but I don't want to use this as a source in my rebuttal because the YEC can accuse it of being bias...I For the first time, I don't know what to do...

The sad truth is that there's probably nothing you can do. I think you're right that he would dismiss talkorigins.org as being "biased". That's another problem with these people. They don't even understand that a) they are biased to an absurd degree, and b) the validity of a given argument doesn't depend on whether the person who came up with it is biased or not.

Nice, and I believe you are correct. You do realize your response statement opens up a can of worms. I love it !

 

[HughMc1]

Mate0,
I agree that there is only one (1) meaning for the word "nothing". That meaning is "Zero (0). But I take exception to your statement that, "the current laws of physics were created then,"; actually only OUR current laws of physics were created then. This universe is our universe [not possession- just 'time']. No one knows, but it is unlikely that our universe became from 'Nothing'. If there was a primordial atom, it was composed of 'something'. That something had to come from somewhere. Of course I don't know from where, but my mind's eye can certainly see a previous universe collapsing upon itself, down to even an 'atom', remaining just long enough to be a logical 'end' of that universe and then be OUR Big Bang! We likely will never know what was before the Big Bang inasmuch as OUR laws of physics started there- OUR time started there. How can you go back in time before there was time [OUR time of course]? This should give you a headache: Has there ALWAYS been "Time"?

 

[HughMc1]

TO ALL:
Remember what Socrates said: "The TRUE test of knowledge is knowing that you know nothing!"

 

[Andy Resnick]

But that's the scary part: It seems that I can't shake him. He showed me a quote of Vilenkin where he said the universe came from nothing, and to my spine crushing surprise, the quote wasn't taken out of context (Or maybe I'm missing something). I looked up talk origins, and it said : "the "nothing" refers not to an empty vacuum spacetime, but rather to a quantum state of the universe in which "space" and "time" have no well-defined meaning (being only approximate, classical concepts)."

but I don't want to use this as a source in my rebuttal because the YEC can accuse it of being bias...I For the first time, I don't know what to do...

My favorite response is "what's north of the North pole"? It's as meaningless a question as "what happened before the big bang"?

 

[pallidin]

My favorite response is "what's north of the North pole"? It's as meaningless a question as "what happened before the big bang"?

Why would a consideration of what happened before the Big Bang be "meaningless"?
Does not any event have a prior causation to some degree or another?

 

[PhanthomJay]

I would argue non scientifically, and I know speculatively, so i pose it as a question: If the Big Bang came from 'something', then that something must have come from 'something else' , which, in turn, must have come from some other 'something else', etc., etc., leading to the inevitable conclusion that 'something' and 'nothing' must be one and the same, just like virtual particle 'somethings' popping into existence from 'nothing'...something and nothing, one and the same...?

 

[pallidin]

But isn't it logically IMPOSSIBLE for "something" to come out of "complete" nothingness?
Please show me just ONE scientific example that demonstrates otherwise.

 

[mate0]

But isn't it logically IMPOSSIBLE for "something" to come out of "complete" nothingness?
Please show me just ONE scientific example that demonstrates otherwise.

yes, it is. The universe did not come from nothing, it is just impossible to determine where it did come from because the current laws governing how our universe works weren't around then.

 

[mate0]

Why would a consideration of what happened before the Big Bang be "meaningless"?
Does not any event have a prior causation to some degree or another?

no, one of the things that was different before the big bang was that time did not progress in the same way we perceive it to now. so cause and effect before the big bang may not go the way we think of it

 

[PhanthomJay]

But isn't it logically IMPOSSIBLE for "something" to come out of "complete" nothingness?
Please show me just ONE scientific example that demonstrates otherwise.

There is much literature written on "Quantum Uncertainty" that spawns the existence of virtual particles (energy packets) from 'empty space'...nothing at all... that exist for extremely brief instants of time before disappearing.

http://science.jrank.org/pages/7195/Virtual-Particles.html

In this regard, though, I would speculate that empty space lacks meaning, because empty space appears to be a sea of virtual particles (energy, per e=mc^2), which leads me to pose the question again: Is Something and Nothing one and the same??

 

[pallidin]

There is much literature written on "Quantum Uncertainty" that spawns the existence of virtual particles (energy packets) from 'empty space'...nothing at all... that exist for extremely brief instants of time before disappearing.

http://science.jrank.org/pages/7195/Virtual-Particles.html

In this regard, though, I would speculate that empty space lacks meaning, because empty space appears to be a sea of virtual particles (energy, per e=mc^2), which leads me to pose the question again: Is Something and Nothing one and the same??

I said "complete" nothing. No space. No time. Thus, no virtual particles.

 

[Oddbio]

I don't know the validity of this, and I admit that I don't really know much about the big bang other than what your average person would know, but I just thought I'd offer it.

What I always understood to be the meaning of "the universe coming from nothing", was that we would have to assume in addition to this that we STILL are nothing. Which I would imagine is something like writing: 0 = 0 or, 0 = 1 - 1, our universe would be like one of the 1's. It's something that comes from nothing.

But again, that's just what I've heard from various places, and what I would imagine is really the only way that "something coming from nothing" might make any sense at all.

 

[vanesch]

Frederik already gave a very good answer in post #3.

He pointed out that the BB theory takes on that our universe can be described by a certain solution to Einstein's equations, essentially the idea that the universe is expanding, and with it, meaning that long ago, the universe had to be denser and hotter. A lot denser and hotter.

It is also a particular feature of this solution (as Frederik pointed out, in ONE version of the BB theory which comes in many variations) that there is a "singularity" to it. However, the conditions of density and pressure and so on near that singularity are so exotic that we can safely say already that the laws of physics we know are probably not valid anymore (including maybe general relativity itself which provided the solution in the first place). So one way of looking at it is saying that although the biggest part of that solution is probably a good description of our universe ("from a certain time onward"), the mathematical complete solution back to the singularity itself is probably an application of a theory outside of its scope of applicability.

A bit like G M/r^2 is a good theory that describes Earth's gravity at a certain distance, but the mathematically complete solution, with an infinite force at r = 0, is wrong, because the application of the equation that gave that solution is not valid any more for a certain r < R.

But another way to look at it is this: this funny solution of Einstein's equation with "no meaning for t < 0" is actually putting our nose upon some very strange property of Einstein's theory of general relativity, but which we didn't maybe appreciate fully: in Einstein's theory, time is a geometrical notion. This changes radically from our Newtonian notion of "time flows uniformly". So maybe we didn't appreciate the enormity of that statement: "time is geometrical", unless we are pushed with our nose upon one of the strange consequences of it. If time is really geometrical, as Einstein puts it, then we must be able to accept that time can be finite (can have a "beginning", just as a rectangle can have a "beginning" and an "end", say). And the basic BB solution just has such a feature, which is not to be surprised about given the premises of general relativity. If time is geometrical, there is not necessarily always a notion of "before" and "after".

 

[pallidin]

I respectfully disagree.

If we can easily notion a future infinity, why can not we see the same for the past?

 

[PhanthomJay]

So if we're talking about the original big bang theory, questions about what happened before, or even at the time of, the big bang, doesn't make sense, because they're asking us to accept as a premise that the theory we're supposed to use to answer the questions is logically inconsistent. The question "Did nothing exist at t=0?" is of that sort, so it can't be answered by that theory, or even asked in a way that makes sense, as long as we're supposed to use that theory to answer it.

But the question that may make sense to ask is 'What happened within the Planck Time, within the first 10^-43 seconds after the "Big Bang" at t=0?" The answer to that one may unlock the secret of the 'nothing', and the universe itself..

 

[Oddbio]

I respectfully disagree.

If we can easily notion a future infinity, why can not we see the same for the past?

But can we really notion a future infinity?
I don't think we have any reasons to say that at all. Just because we as humans in our incredibly limited lifetime here on Earth observe that time seems like it can go on forever, doesn't necessarily mean it will.
But you could also be right I suppose, I don't think I'm qualified to say for sure, but when talking about "notions" you have to be careful.

 

[vanesch]

I respectfully disagree.

If we can easily notion a future infinity, why can not we see the same for the past?

The world lines come also to a "finite future end" in a black hole, so for specific world lines, there is already no "notion of future infinity". If we would have a re-collapsing universe solution, this would be the case for all worldlines, and there would not be a notion of "infinite future". In an ever expanding universe, however, yes. Then there are solutions for all t > 0 (matter of speaking).

As time is, in this paradigm, a geometrical concept, whether it is double or single sided infinite or not, is then purely a matter of the specific "shape" of the geometrical object (the specific spacetime) at hand.

Of course, it might be that the paradigm of "time is a geometrical concept" proves wrong. No scientific theory is free from the possibility of falsification (by definition, I would say!). But as long as we remain within that paradigm (that is, as long as we consider GR as a useful model for the purpose at hand), we shouldn't be surprised that "time" can have a beginning, and end, or can even loop onto itself or do other complicated things. Because time is now not "the uniformly flowing Newtonian time" as it corresponds to our intuition and daily experience.

As someone said here, a good point of comparison is "north of the north pole". People living in a non-polar region, used to limited geographical displacement (say, only walking and horse-riding), would develop the notion that "north" is a direction, something that goes on "for ever" (on a flat earth, say). For them it would be inconceivable to have such a notion as a spot on Earth where you cannot go anymore "north". It is when you understand that "north" is a geometrical concept on a sphere that you can understand that point, and not when you think of it as a "direction in a plane".

But the analogy has its limits, because the north pole is not a singularity of the geometry itself but just of a coordinate system.

I don't want to argue here about the "evidence" of having a finite time, I'm arguing here for the fact that one shouldn't be surprised to find such things in the frame of a paradigm where time is a geometrical notion.