Sunday, August 30, 2009

Big Bang in 2 minutes

Here is a (very) short but cool primer on big bang:



This is an excellent example of the way scientists talk about origins. There is a definite acknowledgment of what we don't know (i.e. "before" the big bang) but then a listing of possibilities. Note that these are possibilities - not certainties. But then scientists are happy to live with unknowns - as that is where hot scientific questions thrive. Ideas of an oscillatory universe, multiverses or Brane-cosmology may all turn out to wrong or one of these may turn out to be correct. However, the verdict on these will only come from testing predictions - not from any theology or a particular religion. The only possible role for God in nature (if any) would have to be a theoretical "first cause" located at the end of an infinite regression of causes: we cannot ascribe "first cause" to big bang - as there may be a natural explanation behind it (and there already are several candidates). But we cannot ascribe a "first cause" to what is behind big bang, as there may be natural explanations behind those, and we me may uncover those sometime in the future. History of science tells us that even when we label a problem "unknowable" - it gets resolved with time. Origin of the Earth was once considered such a problem - so was the origin of the solar system. Both origins are very well understood today. I wouldn't bet against us figuring out the conditions that existed "before" the big bang.

Also see this earlier post Multiverse theory: Leave it to science.

17 comments:

Muhammad Akbar Hussain said...

What about the theology of scienceism?...a blind faith that dictates that every alternative to the possibility of a creator will ultimately be solved.
Ideas of an oscillatory universe, multiverses or Brane-cosmology are as much a "pseudo-science" as any concept of the slightest possibility of the presence of a creator, but we feel to go for the more colorful concepts to teach in our science books or support in our scientific discussions. To me, the above named "scientific" concepts are so fancy that while waiting for them to become testable, creator will already be in the science books since long.

Salman Hameed said...

"Ideas of an oscillatory universe, multiverses or Brane-cosmology are as much a "pseudo-science" as any concept of the slightest possibility of the presence of a creator, but we feel to go for the more colorful concepts to teach in our science books or support in our scientific discussions."

Actually, this was not meant to be included in any textbooks. Of course, at present these are speculative ideas - that is the reasons we don't consider them as facts of science. However, my point was that is a history of such fanciful ideas - and some turn out to be correct and some wrong. But the acceptance or rejection comes from predictions and verification - and antithesis of "blind faith". Some of the "fanciful" ideas of last 150 years include the existence of neutrons, microwave radiation left over from the big bang, a universe that ceaselessly creates matter (steady state cosmology), stars predominantly made up of neutrons and those whose escape velocity exceeds that of the speed of light, aether - that fills the space, light that gets bent by the effects of gravity, and on and on and on. Aether and steady state cosmology got thrown out, whereas other ideas, no matter their fanciful nature when they were proposed, are not part of mainstream science (and now included in textbooks). It is this process of isolating good ideas from the bad ones that is important and will eventually allow us to determine what kind of physics provide answers to conditions before the big bang. Today - yes, these ideas are as fanciful as the prediction of gravitational lensing. Tomorrow - we don't know which of ideas will be successful. But I wouldn't put these questions in the "unknowable" category and that was the point of the post.

Muhammad Akbar Hussain said...

I have a hypothesis in mind. I call it "Infinitely Complex and Perfectly Balanced Nature" hypothesis. (And by infinite, I mean Infinite!) If proven to be correct, what conclusion will it lead us to, can you imagine?
Wouldn't it be a valid testability of a presence of an infinitely intelligent thought or will behind it?
You may ask...how do we ever know the infinite depth of complexity in nature? Let me give you example of Pi, one of the most important mathematical constants in nature, yet we know it only in approximation (π = 3.14159265358979323846.....down to 1012 calculated digits so far, yet still approximate). No one knows the exact value of Pi, and perhaps never will.

Muhammad Akbar Hussain said...

"Infinitely Complex, Ultimately Perfect, and Carefully Balanced Nature" (hypothesis) should be closer to be accurate :-)

Muhammad Akbar Hussain said...

I think the concept of infinity in this complex yet perfect universe is more testable than multiverse concepts etc. Isn't it?

Ali Kazim Gardezi said...

This is a very interesting post. Although I didn't really follow Mr Akbar Hussain's hypothesis :)

We were actually discussing the same (what and who triggered big bang) couple of days back on my facebook profile.

I'm putting it on my facebook profile. Salman sb it's about time you take ur blog to facebook. We'll become 'fan' of ur page :)

Anonymous said...

We need to be more clear about the use of terms such as 'hypothesis' and 'testable'. A hypothesis is a proposed explanation of some phenomenon that is testable. What is "infinitely complex and perfectly balanced" supposed to explain ('everything' is too vague to be testable), and what would constitute a test of it? To say that a hypothesis is testable requires, a) that the claim is clear, specific and well understood; and b) that there is a conceivable way to disprove the hypothesis - that the hypothesis makes a specific enough claim about the way the world is, that it excludes other possibilities. What would be evidence that things are not perfectly balanced? You can see that, to determine this, we would need to agree on what a phrase like 'perfectly balanced' means.

Do multiverses or Brane cosmologies conform to these standards? This is not my field so I don't know but I guess probably not yet. However, I bet that the claims they make are sufficiently well defined and understood to allow for rigorous academic debate. After all they are derived from mathematical models and formulations that are open to objective scrutiny. And I assume they make some predictions that could be developed in to hypotheses that could be shown to be wrong, either through mathematics or empirical test. After all, to be saying something meaningful and interesting, there has to be some possibility excluded by the claim. But, as Salman points out, these are not yet at the status of scientific hypotheses. They are speculations that may generate more concrete hypotheses in the future.

This does not change the fact that many things about the Big Bang are well established scientifically, and those that are not, are the subject of continued study. Both scientists and non-scientists should resist filling any gaps in our knowledge with speculations that will not lead to more and better knowledge.

Muhammad Akbar Hussain said...

Nature is complex...infinitely complex. No matter how deep we go, there is always more. Apparently there is no end to it.
To disprove this, one can prove that there is a limit to how deep we can go and explore and ultimately there is an end...the graininess of nature.

Atif Khan said...

@Akbar,

Can you be specific as what point you are trying to make?

Muhammad Akbar Hussain said...

Atif Khan
In simple English, my point is that there are many un-testable, extremely vague and fancy concepts around trying to explain what is beyond the observable universe, both in space and time. Scienceism would make someone "bet that the claims they make are sufficiently well defined and understood to allow for rigorous academic debate" without feeling a need to know what that concept or speculation actually is. On the other hand, any alternative point to this "accidental universe" concept will be asked repititively to be CLEAR enough before being put in any discussion.
To summarise...if nature is infinitely complex, how is it possible to get created by an "accident" alone in this finite age of the universe?
Clear enough?

Atif Khan said...

@Akbar,

In simple English, I would suggest to read Salman's explanation again if you are willing to comprehend his clear point about your confusion.

Muhammad Akbar Hussain said...

@Atif Khan
I mostly agree to Salman's explanations and that is the reason I visit his blog regularly. His approach is more towards objective models and he derives his reasoning from established facts.
However showing too much faith in science regarding cosmic models like string theory, multiverses, brane cosmology, bubble universe etc. is where I differ. The mentioned history of science does not make any rule. This argument is entirely non-scientific in itself.
Universe is not just a heap of matter and energy that was born at the big bang, it also constitutes space and time as its integral components that were born alongwith this existing universe too. The expanding fabric of space and the direction of time holds important clues. What was before the big-bang?...perhaps nothing, not even time and space. This is what I think Big-Bang model of the Universe suggests. So the question that what was before Big-Band holds no meaning. Age of universe, which is itself a function of time, is finite. The derivatives of the established Big-Bang should hold weightage over alternate explanations, which are nothing based on nothing.

Muhammad Akbar Hussain said...

Finally I am able to run the video on my hospital network computer...which bans youtube or any other video link (yet there is always a way out)
I agree to the first part of the explanation. There is nothing strange about believing that there was nothing prior to the big bang. This is what the current model suggests. Repeated occurence of the big bang and creation of the universe (i.e. time may be infinite) or multiverse or mega universe (i.e. space may be infinite) doesn't really make much sense to me, as it will unleash a flood of every possible explanation one can think of. Such speculative ideas should not get a place when we have more established facts on the contrary.

Atif Khan said...

@Akbar,

I kind of agree with you that there is too much of speculation about origin of everything. Thats where only Science can help. Don't you agree on that? or do you suggest there is something else beside science which can help?

Muhammad Akbar Hussain said...

Atif Khan
This depends upon the how we define science.

Muhammad Akbar Hussain said...

Salman and Atif Khan:
The Big-Bang model of the Universe and Second Law of Thermodynamics are very well established and time tested concepts and augment each other. In fact they are the two faces of the same coin, joined together by the concept of the arrow of time. They both point towards one fact...that the Universe is not there from eternity but from a finite time and had a definite beginning. The Second Law is in fact so profound that Sir Arthur Eddington had to say:

"The law that entropy always increases holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations — then so much the worse for Maxwell's equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation."

There can be many fascinating speculations about the origins of the universe attempting to explain if there was any concept of existence "before" big bang. However if any model of the Universe voilates the second law of thermodynamics and the big-bang model of the universe, I cannot give you any hope too.

Salman Hameed said...

"However if any model of the Universe voilates the second law of thermodynamics and the big-bang model of the universe, I cannot give you any hope too."

Ok - so let me clarify this again. Of course, these ideas about "before" the big bang are speculative - and of course, many of them will turn out to be wrong. But the point here is that they will only be accepted through a process of testing and academic debate. You are correct about the 2nd law of thermodynamics and the quote from Eddington. But if we find sufficient evidence that says that well...2nd law does not apply in certain situations - then no matter what Eddington says - that is the way science will go. By the way, you can also find Einstein adding a constant to make the universe static - when we actually found out that it was expanding. We were expecting the expansion of the universe to be slowing down - but we actually found out that the universe is not only NOT slowing down but it is actually accelerating (dark energy). Speed of light as constant is also being challenged (example VSL theory) - but we don't accept it because sufficient evidence isn't there yet. So who knows about 2nd law of thermodynamics. It is possible that it is completely universal - or it may break down under certain conditions. But only testing and evidence will determine if that is the case or not.

So again, we simply don't know much about the conditions "before" the big bang - and scientists are happy to say that (for example in the video). To say that this is an unknowable problem is jumping the gun a bit. We just don't know.