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Physicist here. Although I am not really a "cosmologist," I have studied cosmology, and have spent a lot of time pondering the the big bang because I think it is interesting, and because so many people like you misunderstand it.

The universe did not come from nothing. Consider the following two claims:

* The universe has a finite age.

* The universe has always existed.

Both of these claims are true. It might seem that if something has always existed, it must have existed for infinitely long. No so. At every time in history, the universe has existed, even though the age is finite.

Your intuition might disagree. But recognize your intuition has been developed under very peculiar circumstances on the surface of the Earth. You should be skeptical of your own intuition when studying things outside of your usual experience. In this case, human intuition says two things:

* There was always something before.

* There was always something 5 minutes before.

In ordinary human life, both claims are true. That's what your intuition says. But for the universe as a whole, only the first claim is true, and the second claim is false. Even though it is true that there was always something "before" (for any time you give me, I can divide that time in two and give you an earlier time), it is nevertheless not true that there was always something 5 minutes before (pick 4 minutes after the big bang, and 5 minutes earlier than that is simply undefined [1]).

Big Bang theory is a self-consistent, meaningful mathematical theory. It does not fly in the face of logical reasoning. Rather, it is a spectacular case-in-point of the power of logical reasoning to describe and explain the universe.

Your second point is that the Big Bang disobeys the first law of thermodynamics, which is the conservation of energy. False. You are assuming there was a period of time when there was no energy, and then suddenly energy came into being. That's not what happened. The energy has always been around, for all time, and thus the first law is not violated.

[1] It so happens that "negative time", or even time t=0, is equally as meaningless as Elephant Time or Verb Time. They are all undefined.

I understand perfectly well your point of view, you don't need to lecture me on it, I've heard it many times before, as I alluded previously.

  The universe did not come from nothing. Consider the following two claims:
  * The universe has a finite age.
  * The universe has always existed.
  Both of these claims are true.

This is a perfect example of the reasoning I described, thank you.

Here's the other bit:

  [1] It so happens that "negative time", or even time t=0, is equally as
  meaningless as Elephant Time or Verb Time. They are all undefined.

I understand this concoction you've formulated, but it isn't very convincing. There's absolutely no evidence that this interpretation of the word "always" is true, and further, it's a violation of Occam's Razor. It would be simpler to take "always" literally, but you are in fact, through what amounts to simple verbal trickery, changing its meaning.

You can state it's "meaningless" to speak of t=0, but you provide zero backup for this, other than it satisfies your fantasy.

You can state it's "meaningless" to ask what happened X minutes before the Big Bang, but again, this is only in the service of satisfying your fantastical theory.

Meanwhile, back in the Universe and the realm of Logic, it's very meaningful to ask what happened at "t=0", because such a state did exist. It even existed in your Big Bang Theory, which states there was an "initial state."

It is highly improbable (if not provably impossible), that such an "initial state" is realistically feasible, and it certainly violates Occam's Razor. Your "initial state" has no explanation. You in fact vehemently object to any attempts at an explanation, deriding them as "undefined." This is faith in its purest form.

Sorry, but I think you are a very religious man and don't realize it. Thank you, however, for the wonderful illustration of my point, I can use it as a historical example of the problem. :-)

To those downvoting me, you're welcome to speak up. This is a game of logic, and I was hoping that this community could keep the religious knee-jerk reactions down to a minimum. :-\

FWIW, I did not downvote you. But you still do not seem to comprehend the fact that the standard theory assumes time is finite. In order to disprove such a theory, you cannot just assume that time is infinite, because you are assuming the conclusion. If you convince me that you actually understand this, I will continue responding to you.

FWIW, I did not downvote you.

I know, HN doesn't allow downvoting of responses. :-p

But you still do not seem to comprehend the fact that the standard theory assumes time is finite.

Really? I thought I was very clear in demonstrating that I understood this through and through, hence the accusation of faith. I did not simply use an assumption that time is infinite as disproof, in fact I did not disprove BBT at all in my response, but merely gave reasons why I thought it was extremely unlikely to have a start.

You sound like a crackpot. You don't sound like you understand physics. You also sound cranky. If you want to have a discussion, you should stop using grandiose language.

itistoday, do you agree that atomic clocks appear to run more slowly as the gravitational field gets stronger?

Yes I do, though shouldn't that line of reasoning be another strike against some of the tenants of the BBT? If you have an infinitely dense object that represents everything, time shouldn't pass, so how could anything have ever gotten anywhere?

Again, no t=0. It never was "infinitely" dense, it just approaches this limit.

You said: it certainly violates Occam's Razor. Your "initial state" has no explanation. You in fact vehemently object to any attempts at an explanation, deriding them as "undefined." This is faith in its purest form.

Occam's Razor says to go with whatever the simplest model is that accurately predicts everything, not just the simplest model.

The Razor is a rule of thumb. If you have multiple theories / models that all accurately explain all observed phenomena, then they're all correct. In fact, since they make the same predictions, they're all equivalent. Occam's Razor basically says "don't waste time with theories that accurately explain the world but also make unfalsifiable / meaningless predictions."

Smugness doesn't constitute an argument. For any statement you make, I can respond "Ha, I knew you'd say that, how naive and predictable!" I can also add "I perfectly understand your position" despite giving no one any reason to believe this is true.

If our physicist friend didn't provide "backup" for his points, it's probably because he's just trying to set you on the right track. You can't reasonably expect someone to lay out the experimental results of every test we've ever run that has led us to assert TBB. And if you're going to persist in claiming that you understand the theory anyway despite all evidence to the contrary, I really doubt it would make any difference.

I am curious how you became so very confident that you are an enlightened genius and all physicists are naive and irrational fools. Especially since physics arrives at it's theories by empirical evidence whereas you seem to arrive at yours by proclaiming inapplicable truisms.

"It so happens that "negative time", or even time t=0, is equally as meaningless as Elephant Time or Verb Time. They are all undefined."

I'm very curious about the assertion that t=0 is meaningless. Is this the conclusion of a line of reasoning, or is it an axiom assumed in order to make the theory work?

It looks like the latter to me, but that may just be because I'm not familiar with the literature and concepts.

In the standard theory, t=0 is a "singularity." Energy density becomes infinite, for example, at t=0. What that really means is that t=0 is undefined in the same sense that 1/0 is undefined.

Consider the function 1/x. For all positive x, 1/x is defined. As you approach x=0 from the right, 1/x approaches infinity. Same thing for the density of the universe. But the point 1/0 itself is undefined, even though the limit is well defined from the right. Likewise, t=0 itself is undefined, even though the density is well defined for all times greater than t=0.

I wouldn't really consider this an "assumption." It is actually a consequence of assuming that the universe is expanding in accordance with the law of gravity and that energy is conserved. The only way to do it is to construct a "metric" ( http://en.wikipedia.org/wiki/Friedmann%E2%80%93Lema%C3%AEtre... ) where a bunch of parameters are undefined at t=0, but well-defined thereafter.

Thanks for the explanation. I think part of my confusion arises from the (apparently) mistaken idea that t=0 is equivalent to "the first moment of time." But it looks like t=0 is closer to "before the first moment of time". In a certain sense, that's a contradiction, because you can't have "before" time, but in another sense it's the only way to speak of that which (logically, not necessarily chronologically) precedes time.

Would you say that's a decent summary, given that I'm translating from scientific terms to more philosophical terms?

> Thanks for the explanation. I think part of my confusion arises from the (apparently) mistaken idea that t=0 is equivalent to "the first moment of time." But it looks like t=0 is closer to "before the first moment of time". In a certain sense, that's a contradiction, because you can't have "before" time, but in another sense it's the only way to speak of that which (logically, not necessarily chronologically) precedes time.

Yes, I think that's right. It's more accurate to say that there was no first moment rather than that t=0 was the first moment. Reconciling that with the fact that time is nevertheless finite is an important part of understanding the big bang.

To put it mathematically, the set of points of time is open on the left end. The set of times is this: (0,\infty). And not this: [0,\infty)

Edit: By the way, when I say that time is "finite", I mean finite from now into the past. Not finite from "start" to "finish". The standard cosmological model with dark energy have time being infinite from "start" to "finish"

Yes, exactly, in the standard theory, the Universe is undefined. :-)

Have fun with that and your "dark energy." I will continue to laugh at you. :-D (And will get downvoted as a result, but it's worth it.)

It so happens that "negative time", or even time t=0, is equally as meaningless as Elephant Time or Verb Time. They are all undefined

But Hammer Time is still okay, right?

If science has taught us one thing, it's that almost always, what once looked like a solid theory, is found to be way more subtle and complex in a later stage.

In addition to this, it's almost impossible to prove something in physics. You can use deduction to support your theory, but you can't prove it in the same way that you can formulate a mathematical proof. That's why it's called a theory: because it's not a proven fact.

However, to make claims like "the universe will always be here, it has always been here, it cannot go away" because otherwise it would violate the first law of thermodynamics is just as bad. The second law of thermodynamics has been haunted by Maxwell's demon for at least a century, and although it does appear to be safe at this point, I wouldn't be surprised if all of this would be proven to be more complex in the future.

So, while you're correct for doubting the big bang theory for too much scientific faith, you might as well put a lot more doubt in other areas as well. A lot of physics is built around faith.

A lot of physics is built around faith.

I would take issue with this, at least when speaking of "faith" as "a belief that is not based on proof". For example, the belief that a god created the world in 7 days is based on faith since there is no evidence to support your belief. On the other hand, belief in the big bang is supported by some evidence.

I meant faith as in, "I have faith in the economy". I think we all know that proofs are a central part of every field of science.

But history has shown that a lot of laws were discovered to be wrong (or incomplete) in the past. Things like the laws of gravity by Newton come to mind. People had a lot of faith in those laws, we're able to send rockets to the moon based on those calculations, but still Einstein managed to show that everything is a lot more complex with his theory of relativity.

Ok, agreed.

The use of the same word as used to describe groundless religious belief just makes me a bit nervous about the connotation.

I would really emphasize "incomplete" here. Newton's laws fully accounted for the phenomena they sought to account for, and gravity really does work like Newton said it would work on the level that Newton was talking about it. The idea that there were things under the surface giving rise to this phenomenon probably would not even have surprised Newton.

"The Universe will always be here. It has always been here. It cannot go away. It is indestructible and everlasting. The mystics understand this, and so does anyone who understands basics physics."

While I'm sure that many mystics have held the idea of an eternal universe, it isn't as universal as you seem to suggest. Virtually all the mystics in the Christian tradition have held that the universe had a beginning. St. Thomas Aquinas is one of the more prominent examples: http://www.newadvent.org/summa/1045.htm

That's a valid point, not everyone labeled a "mystic" holds the same viewpoint. I don't consider Aquinas to be a mystic though. :-p

I should have been more specific, but it's rather difficult to be specific w.r.t. definitions of who is a mystic and who is not, it will likely lead to needless debate. :-\

I just hope that those who have studied a bit of comparative religion (and eastern religions specifically) will know what I'm referring to.

Have you heard of the "No True Scotsman" fallacy?

No, I hadn't, thank you for the tip actually.

However, I did not commit it, I never asserted "true mystics" or anything along those lines. I in fact admitted that my choice of words was poor, and that I was having difficulty choosing a better description.

It is not necessary to use the word "true" to fall into the "No True Scotsman" fallacy.

They key point is that you go around defining the word "X" in a non-conventional way to make sure that your "all X have property Y" is trivially true.

I understand that. :-)

Again, I don't think I committed the "No True Scotsman" fallacy.

Well, I'm not sure if he would meet your criteria for being a mystic, but Aquinas is reported to have had experiences typically labeled "mystical," such as visions of Christ and a deep interior perception of God.

Not trying to argue, but many people don't know that aspect of Aquinas's life. :-)

I have to upvote you here, not particularly because I agree with your sentiments, but because of the relative depth and ability that you express them.

Even if you are 100% wrong, this type of questioning and reasoning is the essence of what it means to be a "hacker" and should be encouraged on this site.

It flies in the face of logical reasoning. Something cannot come out of nothing.

That's not logical reasoning, that's merely a fact derived inductively from everyday observations.

The point above actually has a physical law. It's called the First Law of Thermodynamics, and the Big Bang Theory is in stark violation of it.

Again, the first law of thermodynamics is a "law" which describes everyday experiences within our own universe at the present epoch. But Big Bangs are not everyday in-universe events.

The Universe will always be here. It has always been here. It cannot go away. It is indestructible and everlasting. The mystics understand this, and so does anyone who understands basics physics

That's just an unjustified assertion, and it doesn't really solve anything. Oh, and I'm sure that "the mystics" disagree on these things, as there's plenty who will tell you the universe was belched out of the belly of a giant porpoise. (If you ask them where the giant porpoise came from, they will get angry.)

How and why the universe started, and why we have this universe rather than any other, are two of the trickiest unsolved questions there are, but the Big Bang is the most sensible theory we have at the moment.

That's not logical reasoning, that's merely a fact derived inductively from everyday observations.

No, it's simply definition.

Again, the first law of thermodynamics is a "law" which describes everyday experiences within our own universe at the present epoch. But Big Bangs are not everyday in-universe events.

I've heard this one too, and if there ever was a weak objection to something, this is it. It amounts to: physics is worthless.

as there's plenty who will tell you the universe was belched out of the belly of a giant porpoise.

Your ignorance is showing and it's embarrassing. The mystical experience is remarkably consistent.

Your ignorance is showing and it's embarrassing

I don't think continuing this discussion is likely to be a particularly productive use of my time. I have a paper I should be working on.

Have fun believing whatever it is that you enjoy believing.

The mystical experience is remarkably consistent.

What do you mean by this? To my mind, some definition of "the mystical experience" may be internally consistent, but I highly doubt what you're hinting at makes any testable claims.

I have seen TV shows that were quite consistent. That doesn't make them fact rather than fiction.

Things come from nothing all of the time in the realm of quantum mechanics (see http://en.wikipedia.org/wiki/Vacuum_energy).

Your statement is not true, and the link you provide does not support it.

The spontaneous creation of particle pairs is not at all an example of "something from nothing", but simply an illustration of "something from something". Vacuum energy is not nothing. That should be obvious.

A proper understanding of what "nothing" means would prevent misunderstandings such as this from coming up. Nothing is literally, nothing. Non-existence. In other words, by definition, you'll never find it.