The Big Bang Theory

[Mowgli]

I am a physicist, but I don’t quite understand the Big Bang theory. Let me tell you why.

 

The Big Bang theory says that the whole universe started from a “singularity” — a single point. The first question then is, a single point where? It is not a single point “in space” because the whole space was a single point. The Discovery channel would put it fancifully that “the whole universe could fit in the palm of your hand,” which of course it could not. Your palm would also be a little palm inside the little universe in that single point.

 

The second question is, if the whole universe was inside one point, what about all the points around it? Physicists would advise you not to ask such stupid questions. Don’t feel bad, they have asked me to shut up as well. Some of them may kindly explain that the other points may be parallel universes. Others may say that there are no “other” points. They may point out (as Steven Weinberg does in The Dreams of a Final Theory) that there is nothing more to the north of the North Pole. I consider this analogy more of a semantic argument than a scientific one, but let’s buy this argument for now.

 

The next hurdle is that the singularity is in space-time — not merely in space. So before the Big Bang, there was no time. Sorry, there was no “before!” This is a concept that my five year old son has problems with. Again, the Big Bang cosmologist will point out that things do not necessarily have to continue backwards — you may think that whatever temperature something is at, you can always make it a little colder. But you cannot make it colder than absolute zero. True, true; but is temperature the same as time? Temperature is a measure of hotness, which is an aggregate of molecular speeds. And speed is distance traveled in unit time. Time again. Hmmm….

 

I am sure it is my lack of imagination or incompleteness of training that is preventing me from understanding and accepting this Big Bang concept. But even after buying the space-time singularity concept, other difficulties persist.

 

Firstly, if the whole universe is at one point at one time, one would naively expect it to make a super-massive black hole from which not even light can escape. Clearly then, the whole universe couldn’t have banged out of that point. But I’m sure there is a perfectly logical explanation why it can, just that I don’t know it yet. May be some of my readers will point it out to me?

 

Second, what’s with dark matter and dark energy? The Big Bang cosmology has to stretch itself a bit with the notion of dark energy to account for the large scale dynamics of the observed universe. Our universe is expanding (or so it appears) at an accelerating rate, which can only be accounted for by assuming that there is an invisible energy pushing the galaxies apart. Within the galaxies themselves, stars are moving around as though there is more mass than we can see. This is the so called dark matter. Although “dark” signifies invisible, to me, it sounds as though we are in the dark about what these beasts are!

 

The third trouble I have is the fact that the Big Bang cosmology violates special relativity (SR). This little concern of mine has been answered in many different ways:

• One answer is that general relativity “trumps” SR — if there are conflicting predictions or directives from these two theories, I was advised to always trust GR.
  
• Besides, SR applies only to local motion, like spaceships whizzing past each other. Non-local events do not have to obey SR. This makes me wonder how events know whether they are local or not. Well, that was bit tongue in cheek. I can kind of buy this argument (based on curvature of space-time perhaps becoming significant at large distances), although the non-scientific nature of local-ness makes me uneasy. (During the inflationary phase in the Big Bang theory, were things local or non-local?)
  
• Third answer: In the case of the Big Bang, the space itself is expanding, hence no violation of SR. SR applies to motion through space. (Wonder if I could’ve used that line when I got pulled over on I-81. “Officer, I wasn’t speeding. Just that space in between was expanding a little too fast!”)
  

 

Speaking of space expanding, it is supposed to be expanding only in between galaxies, not within them, apparently. I’m sure there is a perfectly logical explanation why, probably related to the proximity of masses or whatnot, but I’m not well-versed enough to understand it. In physics, disagreement and skepticism are always due to ignorance. But it is true that I have no idea what they mean when they say the space itself is expanding. If I stood in a region where the space is expanding, would I become bigger and would galaxies look smaller to me?

 

Note that it is necessary for space to expand only between galaxies. If it expanded everywhere, from subatomic to galactic scales, it would look as though nothing changed. Hardly satisfying because the distant galaxies do look as though they are flying off at great speeds.

 

I guess the real question is, what exactly is the difference between space expanding between two galaxies and the two galaxies merely moving away from each other?

 

One concept that I find bizarre is that singularity doesn’t necessarily mean single point in space. It was pointed out to me that the Big Bang could have been a spread out affair — thinking otherwise was merely my misconception, because I got confused by the similarity between the words “singularity” and single.

 

People present the Big Bang theory in physics pretty much like Evolution in biology, implying the same level of infallibility. But I feel that it is disingenuous to do that. To me, it looks as though the theory is so full of patchwork, such a mathematical collage to cook up something that is consistent with GR that it is hard to imagine that it corresponds to anything real (ignoring, for the moment, my favorite question — what is real?) But popular writers have embraced it. For instance, Ray Kurzweil and Richard Dawkins put it as a matter of fact in their books, lending it a credence that it perhaps doesn’t merit.

 

[This post is from a recent entry in my "Unreal Blog." Hope you like it!]

[Kyrisch]

Your inability to think of the singularity as a point where there are no other points is simply a limit to your imagination. Not many can actually wrap their minds about it, but it is not a mathematical nor physical impossibility -- it violates no presuppositions. Furthermore, there would be no before in the same way there would be no anywhere else. Time and space are functionally identical.

 

Second, simply put, a black hole is a product of mass contorting that fabric of spacetime the same way any other gravitational wells work. The singularity, however contained spacetime itself, it was not embedded therein. This is similar in concept to your previous contention.

 

And as for the difference between the expansion of space and the moving away of bodies, is that first, many galaxies are receding faster than the speed of light and second, if they were simply moving away, we would have to consider ourselves the center of the universe. Therefore, it's more common (and of course, consistent with the evidence) to view the space itself as expanding such that every point is receding from every other one.

[Severian]

I am a physicist

 

Are you sure about that? Your first two objections (I stopped reading after that) are pure misunderstanding of what the BB model is, and I would have thought that any physicist should be able to tell you where you are going wrong.

[Martin]

I am a physicist,...

 

Are you sure about that? Your first two objections (I stopped reading after that) are pure misunderstanding of what the BB model is, and I would have thought that any physicist should be able to tell you where you are going wrong.

 

Mowgli has been completely open about his realworld identity. He often refers us to articles in his blog "Unreal Blog", which is the blog of Manoj Thulasidas. The blog contains lots of information about the author, a many-sided individual, so I am not revealing anything which he wishes to conceal if I say yes he got a PhD in physics from Syracuse, then worked some five years or so in experimental particle physics, and is now working as a finance quant in Singapore. There is a short bio, and a longer CV, at the blog, at the Thulasidas website. Here is the short bio:

 

http://www.thulasidas.com/about/about-me

 

===quote from the blog at Manoj's website===

About Me

 

I’m an amateur philosopher, professional quant, obsessive physicist and an optimistic writer. Surprisingly, in all these different endeavors, I had some measure of success. I have published a book on the philosophy of physics. My columns appear regularly in a high profile quantitative finance publication called the Wilmott Magazine and in a Singaporean newspaper called Today. I also think of myself as an okay human-being!

 

People tend to get impersonal when they pat themselves on the back. So, here is a short biographical sketch in third person: “Manoj Thulasidas was born in the picturesque hill resort of Munnar in south India in 1965. He received his undergraduate degree from the Indian Institute of Technology, Madras in 1987. Guided by his affinity for physics, he then joined the Physics Department of Syracuse University as a graduate student. He studied fundamental particles and interactions at the CLEO collaboration at Cornell University during 1990-’92. After receiving his Ph.D in 1993, the author moved to Marseilles, France and continued his research with the ALEPH collaboration at CERN, Geneva. During his 10-year career as a research scientist in the field of high energy physics, he co-authored over 190 publications. Always inquisitive about the interplay between mind and matter, perception and philosophy and their implications in physics, the author joined the Kent Ridge Digital Labs (KRDL, later to be renamed I2R) in Singapore in 1998 to study and develop various human body-based measurements and systems. His work in this institute resulted in four invention disclosures, two of which have been filed for patent, and numerous academic papers. (Please see the CV for selected publications.) In the last two years, he has been involved in the NeuroInformatics group, focusing on Brain Machine Interface and neural signal acquisition and processing, which gave him the perfect opportunity to further understand and appreciate the role of perception in physics. The Unreal Universe is in part the outcome of the insights gained during the author’s professional research career, in addition to his philosophical bend of mind.”

 

* Want a longer biography?

* More about me at my home page.

* Contact me.

* LinkedIn profie … if you got’em, flaunt’em!

* FaceBook Profile … battling the mid-life crisis!

* Check out my CV

=====endquote=====

 

There is a great deal more one could say about Manoj's talents and attainments, his writings, his success in various different lines of activity. However this is enough for me to say that I consider him a physicist. There are many different kinds of physicist, and he is his own kind. And I respect that.

 

So I propose that we take a look at what Manoj has to say about Big Bang cosmology. But remember that he is not claiming to be a specialist in this area. He is not a cosmologist. So he may be completely wrong in what he says about standard Big Bang cosmology. And if he is mistaken about whatever points, I don't intend to hold that against him. Cosmology has changed a lot over the past ten years and it's easy to be out of touch and need to catch up. So let's see what he says.

 

My goodness! I started reading the post and almost the first thing I see is that Manoj has copied a discussion he had with me and Swansont

(Universe---Size and Age) in March 2007 into his blog!

http://www.thulasidas.com/2007-03/universe-size-and-age.htm

I believe this is a perfectly straightforward and legitimate thing to do, but it feels a bit odd to be part of a conversation that has migrated from SFN here over to a blog in Singapore! This feels like globalization, with a dash of international fame thrown in

 

Here is the SFN thread (Universe--Size and Age) from March 2007:

http://www.scienceforums.net/forum/showthread.php?t=25634

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

Mowgli,

In that March 2007 thread, astronomers had seen a galaxy that was 13 billion LY away, and you reasoned that this must mean the universe is 26 billion LY old! That is, 13 billion years for the galaxy to get that far away from us (if we start as a single point and separate at the speed of light) and then an additional 13 billion years for the light to reach us.

 

This reveals some misunderstanding of the standard cosmo model. Are you all right with that now? Or are you still wondering how the universe can be just 13.7 billion years old even tho we see galaxies at redshift 1.4 and indeed much farther away than that. (I'm just a retired mathematician who has done some teaching, so I don't speak authoritatively, but I've studied the subject a fair amount.)

I can tell you are a smart guy, though you may be trying to cover too many fields, and lack the time to get into depth in some of them.

At any rate I hope we can converse constructively.

Edited November 2, 2008 by Martin

[Mr Skeptic]

Thanks for looking him up, Martin. At first glance I thought he was, well, not worth reading the whole post.

 

The Big Bang theory says that the whole universe started from a “singularity” — a single point. The first question then is, a single point where? It is not a single point “in space” because the whole space was a single point. The Discovery channel would put it fancifully that “the whole universe could fit in the palm of your hand,” which of course it could not. Your palm would also be a little palm inside the little universe in that single point.

 

That nonsense (in my opinion) about being in one point is called a singularity. Nobody really likes singularities, and most folks think they point to a failure in the theory at that point. The point is a regression, extrapolating the expansion of the universe backwards to the maximum, a single point. However, a single point cannot expand as far as I know. As to where the point would be, that is an interesting but unanswerable question.

 

A mathematical analogue is that there are just as many real numbers between 0 and 1 as between minus infinity and plus infinity. In fact, there are as many in the smallest interval you can get. But not if you choose a point instead of an interval. You can't stretch a point.

 

The second question is, if the whole universe was inside one point, what about all the points around it? Physicists would advise you not to ask such stupid questions. Don’t feel bad, they have asked me to shut up as well. Some of them may kindly explain that the other points may be parallel universes. Others may say that there are no “other” points. They may point out (as Steven Weinberg does in The Dreams of a Final Theory) that there is nothing more to the north of the North Pole. I consider this analogy more of a semantic argument than a scientific one, but let’s buy this argument for now.

 

I'd say that the universe was not inside one point. Arbitrarily small, perhaps, but not a point.

 

The next hurdle is that the singularity is in space-time — not merely in space. So before the Big Bang, there was no time. Sorry, there was no “before!” This is a concept that my five year old son has problems with. Again, the Big Bang cosmologist will point out that things do not necessarily have to continue backwards — you may think that whatever temperature something is at, you can always make it a little colder. But you cannot make it colder than absolute zero. True, true; but is temperature the same as time? Temperature is a measure of hotness, which is an aggregate of molecular speeds. And speed is distance traveled in unit time. Time again. Hmmm….

 

I too have a problem with time starting/ending at the BB. However, I have no problem with our time starting at the BB, but I think there had to be some kind of time before that. However, that is pure speculation until we figure out how to make a universe.

 

I am sure it is my lack of imagination or incompleteness of training that is preventing me from understanding and accepting this Big Bang concept. But even after buying the space-time singularity concept, other difficulties persist.

 

Even the experts don't really understand it all. Much like what is inside a black hole, what is outside our universe (in space or time) is beyond our reach. We can make theories and guess though.

 

Firstly, if the whole universe is at one point at one time, one would naively expect it to make a super-massive black hole from which not even light can escape. Clearly then, the whole universe couldn’t have banged out of that point. But I’m sure there is a perfectly logical explanation why it can, just that I don’t know it yet. May be some of my readers will point it out to me?

 

I asked something similar. I asked why our universe is not a black hole, since given any non-zero matter density, at a large enough radius there would be enough matter inside the Schwarzschild radius to form a black hole. However, I was told that that wouldn't work because the expansion of the universe violates the assumptions of the Schwarzschild black holes, which incidentally are the simplest type. Perhaps something similar is the reason for the universe not collapsing into a black hole at that time. I think your question is also related to the question of whether the universe will continue to expand indefinitely, or collapse again.

 

Second, what’s with dark matter and dark energy? The Big Bang cosmology has to stretch itself a bit with the notion of dark energy to account for the large scale dynamics of the observed universe. Our universe is expanding (or so it appears) at an accelerating rate, which can only be accounted for by assuming that there is an invisible energy pushing the galaxies apart. Within the galaxies themselves, stars are moving around as though there is more mass than we can see. This is the so called dark matter. Although “dark” signifies invisible, to me, it sounds as though we are in the dark about what these beasts are!

 

I think "dark" signifies "we don't know". Dark matter is a way of taking data that could be used to figure out a new theory of gravity. Or, we might be able to discover dark matter with some collider experiments. Dark energy seems even more suspicious to me.

 

The third trouble I have is the fact that the Big Bang cosmology violates special relativity (SR). This little concern of mine has been answered in many different ways:

• One answer is that general relativity “trumps” SR — if there are conflicting predictions or directives from these two theories, I was advised to always trust GR.
  
• Besides, SR applies only to local motion, like spaceships whizzing past each other. Non-local events do not have to obey SR. This makes me wonder how events know whether they are local or not. Well, that was bit tongue in cheek. I can kind of buy this argument (based on curvature of space-time perhaps becoming significant at large distances), although the non-scientific nature of local-ness makes me uneasy. (During the inflationary phase in the Big Bang theory, were things local or non-local?)
  
• Third answer: In the case of the Big Bang, the space itself is expanding, hence no violation of SR. SR applies to motion through space. (Wonder if I could’ve used that line when I got pulled over on I-81. “Officer, I wasn’t speeding. Just that space in between was expanding a little too fast!”)
  

 

Special relativity starts with "assuming an inertial reference frame", whereas general relativity can account for an accelerating frame. (The universe is an accelerating frame) As a physicist, you should really know that.

 

Speaking of space expanding, it is supposed to be expanding only in between galaxies, not within them, apparently. I’m sure there is a perfectly logical explanation why, probably related to the proximity of masses or whatnot, but I’m not well-versed enough to understand it. In physics, disagreement and skepticism are always due to ignorance. But it is true that I have no idea what they mean when they say the space itself is expanding. If I stood in a region where the space is expanding, would I become bigger and would galaxies look smaller to me?

 

Note that it is necessary for space to expand only between galaxies. If it expanded everywhere, from subatomic to galactic scales, it would look as though nothing changed. Hardly satisfying because the distant galaxies do look as though they are flying off at great speeds.

 

I guess the real question is, what exactly is the difference between space expanding between two galaxies and the two galaxies merely moving away from each other?

 

From what I understood, the forces between nearby objects are enough to counter the expansion.

 

One concept that I find bizarre is that singularity doesn’t necessarily mean single point in space. It was pointed out to me that the Big Bang could have been a spread out affair — thinking otherwise was merely my misconception, because I got confused by the similarity between the words “singularity” and single.

 

Yes, an arbitrarily small bit of space makes far more sense than a point.

 

People present the Big Bang theory in physics pretty much like Evolution in biology, implying the same level of infallibility. But I feel that it is disingenuous to do that. To me, it looks as though the theory is so full of patchwork, such a mathematical collage to cook up something that is consistent with GR that it is hard to imagine that it corresponds to anything real (ignoring, for the moment, my favorite question — what is real?) But popular writers have embraced it. For instance, Ray Kurzweil and Richard Dawkins put it as a matter of fact in their books, lending it a credence that it perhaps doesn’t merit.

 

[This post is from a recent entry in my "Unreal Blog." Hope you like it!]

 

As to what is real, that is a tricky question and would have to have its own thread to answer it.

[Martin]

Mowgli,

first let me say that I hope you stay around---I think the exchange of ideas would be good for SFN. Also I think your blog has potentially a large readership of intelligent laymen. Just thinking of the Kerala state and the Tamil Nadu population alone is a lot. (And of course you are obviously aiming at a world audience, not only South India and Singapore.)

 

I'd be interested to know the traffic figures for your blog, and how the sales of your book are going. Also do you have a second book in mind or in the works?

 

Anyway, back to business.

 

You should read Abhay Ashtekar's October 2008 review article, especially the first 15 pages:

 

If I had to recommend just one article giving an overview of the current state of research in quantum cosmology, it would be this October 2008 paper by Ashtekar.

http://arxiv.org/abs/0810.0514

It gives a history of QC and some deep reflections on where the field is going, as well as a current status report. It has very few equations, he mostly says in words what he has to say. However the vocabulary is technical. It was an address given to a conference of fellow scientists commemorating the Minkowski centennial. So a lot of the paper is tough going in parts, but it's still useful. If you can read just 10 pages out of the total 31, you can get the man's honest view of where we are.

 

For online public outreach writing on quantum cosmology, there are a few articles at Einstein Online that deal with the subject in general terms. Links are down at the bottom of this page:

http://www.einstein-online.info/en/spotlights/cosmology/index.html

[Severian]

Mowgli has been completely open about his realworld identity. He often refers us to articles in his blog "Unreal Blog", which is the blog of Manoj Thulasidas. The blog contains lots of information about the author, a many-sided individual, so I am not revealing anything which he wishes to conceal if I say yes he got a PhD in physics from Syracuse, then worked some five years or so in experimental particle physics, and is now working as a finance quant in Singapore.

 

I had read his blog profile before posting. My question remains. Not only is he a "physicist", he is a physicist working on (or at least has worked on) an area where cosmological arguments play a role. Maybe it says more about Syracuse that the OP though...

 

So let me answer the first few questions:

 

The Big Bang theory says that the whole universe started from a “singularity” — a single point.

The Big Bang model does not say this at all. The BB model describes the evolution of the universe from a (very short) time after any possible implicit creation event to the present. It says nothing about the times before this and makes no attempt to explain creation. Indeed, we know nothing (or very little) about physics above the TeV scale.

 

The second question is, if the whole universe was inside one point, what about all the points around it?

They are still there! Since the Big Bang has no singularity, it is better to describe your "universe in a point" conjecture by saying that in the limit where we take time to 0, the distance between any 2 points tends to zero. Every point is still surrounded by infinitely many points just like at any other time. The only difference is that points which will later be very far apart, are at this time really really close together.

 

So before the Big Bang, there was no time. Sorry, there was no “before!” This is a concept that my five year old son has problems with. Again, the Big Bang cosmologist will point out that things do not necessarily have to continue backwards — you may think that whatever temperature something is at, you can always make it a little colder. But you cannot make it colder than absolute zero. True, true; but is temperature the same as time? Temperature is a measure of hotness, which is an aggregate of molecular speeds. And speed is distance traveled in unit time. Time again. Hmmm….

A better analogy would be to ask if you are happy with there being no point on Earth further north than the North pole?

 

Firstly, if the whole universe is at one point at one time, one would naively expect it to make a super-massive black hole from which not even light can escape.

Naively perhaps, but since we don't have a theory of quantum gravity, is your conjecture based upon anything other than speculation?

 

Second, what’s with dark matter and dark energy?

Well, we don't have a concrete explanation for these yet, though a wimp and a cosmological constant would do just fine. What is your problem with these?

 

The third trouble I have is the fact that the Big Bang cosmology violates special relativity (SR).

I presume you are referring to inflation here. If so, then SR is only restricting the speed of real physical things, like particles, stars or galaxies, whereas in inflation it is really the particle horizon which is expanding. So the faster then light bit of inflation is a bit like how an infinitely bright spotlight shining on clouds would move faster than light if you reduce the angle enough.

 

Speaking of space expanding, it is supposed to be expanding only in between galaxies, not within them, apparently. I’m sure there is a perfectly logical explanation why, probably related to the proximity of masses or whatnot, but I’m not well-versed enough to understand it. In physics, disagreement and skepticism are always due to ignorance. But it is true that I have no idea what they mean when they say the space itself is expanding. If I stood in a region where the space is expanding, would I become bigger and would galaxies look smaller to me?

Well, your size is governed by the strength of the electromagnetic interaction - not gravity. So you would not expand. Galaxies not expanding are a bit harder to understand, since their size is gravity induced. However, it comes down to the clumpiness of matter - the expansion comes about because the universe is very uniform on large distance scales (ie. it is with this ansatz that the expanding metric is a solution to the GR equations). For clumped matter, the equations are quite different, and the non-expansion of galaxies falls out.

 

[This post is from a recent entry in my "Unreal Blog." Hope you like it!]

Isn't reposting material from blogs a violation of SFN rules?

[Martin]

So what's with Mowgli?

I expected him to get back to us.

Has anybody checked his blog "Unreal Blog" to see if he made any use of our responses?

 

If I understand his blog style, he tries to provoke responses from us at SFN which he can then use to patch together a kind of dialog at his own site. His preferred stance is that of a modest, humble questioner who upholds the commonsense of intelligent laymen against absurd-sounding pontification by those he identifies as scientists. So if I understand correctly, what he will select is quotes from us that sound authoritarian and contrary to commonsense lay intuition.

 

It creates a kind of quasi-theater in which he is the sympathetic everyman and we are the stuffy boffins. This will make him popular with his readers, and help him sell his book or books, and help build blog traffic.

 

There is another side to things----I think Mowgli also really wants to learn some cosmology. That's why I recommended the article by Abhay Ashtekar--currently I'd say the world's top quantum cosmologist. President of the relativists and cosmologists professional society GRG (general relativity and gravitation) and recipient of many honors. A major change is happening in cosmology. If Mowgli really is interested in today's ideas, rather than just making fun of yesterday's, then he will read the article and get back to us. We'll see.

[Mowgli]

Sorry about the delay, got side-tracked with some personal issues.

 

I was working on a reply (as below), but wanted to provide links to a couple of articles, which I may add by editing this post later.

 

Strange that you should recommend Abhay Ashtekar -- he taught me QM during my graduate school years. (Not that it improves my credibility.) I will certainly read the article though.

 

[...]

So I propose that we take a look at what Manoj has to say about Big Bang cosmology. But remember that he is not claiming to be a specialist in this area. He is not a cosmologist. So he may be completely wrong in what he says about standard Big Bang cosmology.

[...]

This reveals some misunderstanding of the standard cosmo model. Are you all right with that now? Or are you still wondering how the universe can be just 13.7 billion years old even tho we see galaxies at redshift 1.4 and indeed much farther away than that.

Thanks Martin. I think I got over the 13.7 billion year hurdle -- Swansont pointed out that light travel time might have been included in the calculation, and you pointed out that the singularity could have an infinite extent in space. Though not satisfied with the validity of BB, I can accept these arguments.

 

My main beef is this: what does it mean to say that space-time expands when we cannot clearly articulate what space and time are?

 

One sensible definition of space is that it is a cognitive construct (much like smell or sound) or a representation of our sensory inputs, which is a view readily embraced in philosophy and neuroscience. Attributing a reality to space that it probably doesn't have, and then imagining its asymptotic and singular properties is a bit weird.

 

The perceptual view of space, though it might sound too philosophical to be useful, was behind my last physics paper published in IJMP-D, which suggested models to certain astrophysical observations. I'm trying to get a sequel (looking at cosmological features) published, but no luck so far.

 

The Big Bang theory, to me, looks like a big leap of faith in terms of its agreement with observations. You know, if you have n+1 points in a 2-D space, you can always find an nth degree polynomial that will go through them. But it is a stretch to call it a model/theory explaining the points. Same with BB. Of course, the skepticism of an ex-physicist is no commentary on the validity of a well-accepted theory. But I wonder, do people actually think long and hard before accepting a theory? Or do they just blindly trust their professors and text books?

 

But you are right, I should invest more time to understand what modern cosmology says, although I may not accept it in the end anyways.

 

Mowgli,

first let me say that I hope you stay around---I think the exchange of ideas would be good for SFN. Also I think your blog has potentially a large readership of intelligent laymen. Just thinking of the Kerala state and the Tamil Nadu population alone is a lot. (And of course you are obviously aiming at a world audience, not only South India and Singapore.)

 

I'd be interested to know the traffic figures for your blog, and how the sales of your book are going. Also do you have a second book in mind or in the works?

 

Hi Martin,

 

Again, apologize for the delay.

 

My blog has fairly poor traffic -- about 30 to 50 hits a day, probably more than half of them from my friends. The best day I had so far was 102 hits. The trouble with the blog is it is not focused, much like its author. I know that I could greatly improve the traffic if I picked just one topic -- say quantitative finance. But that's just not me...

 

I don't think I have any general readership at all in India, and very little in Singapore. Any way, my current tracking program doesn't give any geographic break down.

 

The book is also doing badly, haven't broken even yet. Luckily I have day job that pays well. At least, so far -- you never know with the current financial meltdown.

 

My next book is going to be on quantitative finance. It is a project proposed by a prestigious publisher. I'm looking forward to working on it, but it will limit the amount of time I have to pursue cosmology and philosophy and these debates and so on...

 

Thanks for Ashtekar's paper. Going through it now...

Edited November 3, 2008 by Mowgli
multiple post merged

[Martin]

Strange that you should recommend Abhay Ashtekar -- he taught me QM during my graduate school years. ... I will certainly read the article though.

..

 

What a nice coincidence! I only get up thru page 15---after that he's talking about resolving the blck hole singularity and I can't follow, so I skip to the conclusions at the end. What I'm saying is don't worry if much of the article is incomprehensible, there's definitely stuff that IS comprehensible so look on the bright side.

 

Sorry to hear that blog and booksales are not booming, my take is you are original and bright enough that they deserve to be, but the next book (on finance and quantery) could always be a hit.

 

Very glad to see you back! I disagree with your views of Bang theory of course but might enjoy discussing that. Keeping the conversation light until your reallife pressure is off and perhaps also until I hear your next round of thoughts.

Edited November 3, 2008 by Martin

[Mowgli]

Thank you all for your replies, and thanks Martin for referring me to Ashtekar's paper. After reading and thinking about it, I realized what my trouble with the Big Bang theory was. I thought I would summarize my findings here, more for my own benefit than anybody else's.

 

Classical theories (including SR and QM) treat space as continuous nothingness; hence the term space-time continuum. In this view, objects exist in continuous space and interact with each other in continuous time.

 

Although this notion of space time continuum is intuitively appealing, it is, at best, incomplete. Consider, for instance, a spinning body in empty space. It is expected to experience centrifugal force. Now imagine that the body is stationary and the whole space is rotating around it. Will it experience any centrifugal force?

 

It is hard to see why there would be any centrifugal force if space is empty nothingness.

 

GR introduced a paradigm shift by encoding gravity into space-time thereby making it dynamic in nature, rather than empty nothingness. Thus, mass gets enmeshed in space (and time), space becomes synonymous with universe, and the spinning body question becomes easy to answer. Yes, it will experience centrifugal force if it is the universe that is rotating around it because it is equivalent to the body spinning. And, no, it won't, if it is in just empty space. But "empty space" doesn't exist. In the absence of mass, there is no space-time geometry.

 

So, naturally, before the Big Bang (if there was one), there couldn't be any space, nor indeed could there be any "before." Note, however, that the Ashtekar paper doesn't clearly state why there had to be a big bang. The closest it gets is that the necessity of BB arises from the encoding of gravity in space-time in GR. Despite this encoding of gravity and thereby rendering space-time dynamic, GR still treats space-time as a smooth continuum -- a flaw, according to Ashtekar, QG will rectify.

 

Now, if we accept that the universe started out with a big bang (and from a small region), we have to account for quantum effects. Space-time has to be quantized and the only right way to do it would be through quantum gravity. Through QG, we expect to avoid the Big Bang singularity of GR, the same way QM solved the unbounded ground state energy problem in the hydrogen atom.

 

What I described above is what I understand to be the physical arguments behind modern cosmology. The rest is a mathematical edifice built on top of this physical (or indeed philosophical) foundation. If you have no strong views on the philosophical foundation (or if your views are consistent with it), you can accept BB with no difficulty. Unfortunately, I do have differing views.

 

My views revolve around the following questions. (These are links to posts in my blog. If you feel that I'm trying to promote my blog in this forum, please indicate it in this thread and I will cut and paste here.)

 

• What is space?
  
• Why is the speed of light important in it?
  
• Where does the Heisenberg Uncertainty Principle come from?
  

These may sound like useless philosophical musings, but I do have some concrete (and in my opinion, important) results, listed below. These are again links to my blog.

 

• Are GRBs and Radio Sources Luminal Booms? (An article published in IJMP-D, which became one of the "Top Accessed Articles" of the journal. )
  
• Light Travel Time Effects and Cosmological Features (Trying to get this one published.)
  

There articles are my efforts to sound like a "boffin" !

 

There is much more work to be done on this front. But for the next couple of years, with my new book contract and pressures from my quant career, I will not have enough time to study GR and cosmology with the seriousness they deserve. I hope to get back to them once the current phase of spreading myself too thin passes. Then I will be back with more posts, and hopefully with more results.

 

Sorry for the delay in getting back to the thread. I was trying to put together the articles/post linked to here the whole of last week.

[Edtharan]

Although this notion of space time continuum is intuitively appealing, it is, at best, incomplete. Consider, for instance, a spinning body in empty space. It is expected to experience centrifugal force. Now imagine that the body is stationary and the whole space is rotating around it. Will it experience any centrifugal force?

 

It is hard to see why there would be any centrifugal force if space is empty nothingness.

Most examples of "spinning bodies in empty space" are really composite objects (planets, people, buckets of water, etc), as such particles on one side of the object are in motion (and in acceleration) relative to particles on the other side of the object.

 

Think about it this way. If you had a solar system spinning in empty space (like they do) would you expect each planet to experience a "centrifugal" force in relation to the other planets as they orbit the sun?

 

Of course, because in the solar system you can easily see that the planets are not the same object. However, with an object like a person, we tend to think of them as a "Solid" object, but in reality they are a composite object made up of atoms.

 

The question should be: Does a fundamental point like particle with spin experience centrifugal/centripetal force?