Posted on 12/14/2010 7:27:22 PM PST by SunkenCiv
In Once Before Time, Martin Bojowald explains how he developed the idea of loop quantum gravity and how it will soon be put to the test.
At the moment of the big bang, our universe emerged from a state of infinite density, a point in space and time so small it had no size at all. This, the standard cosmological story tells us, is the singularity, the seed of creation. Singularities can also serve as seeds of destruction, lurking in the centres of black holes, the final endpoints of total gravitational collapse.
Many physicists, however, believe singularities do not mark the ends of space and time but rather the limits of the theory we use to describe them. That theory is general relativity and, according to Martin Bojowald, it's suicidal. When it jumps off a ledge, physicists need a more fundamental theory to take over, one that incorporates what they've learned about the quantum nature of the world - a theory of quantum gravity.
The majority of physicists have turned to string theory as their quantum gravity theory of choice. But a smaller group of physicists has been working on a theory known as loop quantum gravity. According to LQG, space-time on the quantum scale is not smooth and continuous but discrete, built of tiny loops linked and knotted to form a space-time mesh.
Bojowald was 27 years old when he took the equations of LQG and used them to see what happens to space-time near the big bang's singularity. In doing so, he discovered something amazing, and founded the field of loop quantum cosmology (LQC) in the process. Once Before Time tells the story of Bojowald's discovery and its implications in fascinating, eloquent, even literary prose.
(Excerpt) Read more at newscientist.com ...
I only knew one verse of that, but remembered it since I first heard it in the early ‘40’s. Thanks for posting. What’s the origin of that?
http://www.metafilter.com/51472/Two-dead-boys-got-up-to-fight
Nah, I think it's fun to try to figure out how He did it.
And this big bang produced only one planet that could exist to support Life as we know it. That we have found.
There is such a thing as astrophysics, if the stars are forced to obey Laws passed by a bunch of dead white men.
“We may call really really large and small numbers “infinite”, but in reality, they are just really really large and small numbers.” ...Me
What if one of these guys is wrong and he succeeds only in destroying our universe....who do I sue?
He discovered that as we trace the universe's evolution back in time we find that near the singularity too much energy tries to cram into the finite loops. When the loops can't absorb any more, they expel energy. The effect is a repulsive force that counteracts the inward pull of gravity, preventing total collapse. But there's another, stranger side effect as we continue back in time: the repulsive force swaps space's orientation. Instead of contracting into the would-be singularity, space-time begins expanding again on the other side, creating an inside-out looking-glass universe on the other side of the big bang.He "discovered" this, did he?
And how, exactly, did he "discover" all this?
He obviously didn't ride a timespace machine back to the beginning to "discover" this.
He "discovered" this by running some equations that gave him some other equations and then -- the actual magical step in the whole process -- he interpreted the resulting equations to mean all those words about an inside-out looking-glass universe.
What I'm interested in is that interpretation process. How, exactly, did his equations tell him everything in that paragraph I just quoted?
How does this process of discovery actually work?
I don't think the idea is arrogant at all. Given the God is infinite and we can observe that the universe is expanding, it's entirely possible AND within His power to have created the universe (rather, the parts of it that we can perceive) out of nothing at all, or from an impossibly small and equally unimaginably dense spec of dust that He created out of nothing at all, or by clapping His hands, or any other permutation.
To impose limits on what God could or could not have done at the point of Creation on the basis of what's currently plausible and what would've seemed plausible two thousand years ago, is the worst kind of arrogance. God was capable of doing it any-which-way-He-liked-whether-you-like-it-or-understand-it-or-not. We will never, EVER be able to gasp the sheer majesty of what He did. The more science explores the "how", the more complicated it gets, and that's the strongest advocate for the Divine.
Genesis 1 doesn't tell us HOW those things came to be, only that God ordained them to come into being, and it was done that way for one reason only - to avoid confusing primitives with technobabble. And, if the Bible was written today, it STILL wouldn't tell us how these things came to be... because it would STILL confuse us primitives with technobabble.
>>space-time mesh
space-
timemesh
There, fixed it.
Time, being a derivative function of state change that progresses relative to E within the context of the inertial frame(s) in which it is observed...
All your Matrix/Multiverse are berong to us. NO SALE.
Its all a theoretical mathematical exercise.
With all due respect, the article is about The Big Bang, not the Creation.
Its all a theoretical mathematical exercise.But as LomanBill points out, there is a practical, and quantifiable, aspect to the exercise: receiving government grant money.
How does a mathematical model turn into a government grant when its all nothing but theory? Even that’s a stretch considering the author admits that this is really somewhere in between a hypothesis and a theory.
Considering that there is no practical or tangible deliverable other than a check of someone’s math homework one would think that without a practical application in mind, it would be pointless to fund.
But then again, liberals would fund a pissing in the wind contest if it would advance an agenda like AGM. Hell, NASA’s primary mission now is to improve Islamic understanding... so perhaps you have a point.
But I'm sure there are those who are not so limited!
The current models yield two possibilities. Infinite matter and energy, or they admit they do not know. ‘Renormalization’ sounds better than ‘no clue’.
“Let there be light.”
That’s usually best, although most books in general (and it’s particularly true of science titles, afaik) wind up remaindered at low prices crazy quickly. This title is available for the Kindle, I just didn’t plaster in the link for the other editions.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.