« einstein, pi, and the universe | Main | choice and bias »

03/22/2014

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Jean Russell

I love warping it with plastic warp. <3 can you do a future post on how you warp? This must be a physics thing.

Jheri

This helps a lot Steve. I read a few accounts that were too confusing and simplistic. I have a few questions burning. Can you explain why this twirling B-mode polarization is that way? Do only gravity waves cause that? Can you explain inflation to someone like me? What is currently meant by the Big Bang? An account in the paper here said the Big Bang was a “singularity” - what is that and is that correct?

steve

Good questions Jheri.

I can probably explain inflation with a bit of hand waving, but some of the reasoning as well as the result are very counter intuitive. You have to start out with the fact that a gravitation field has negative energy and the total energy of the Univere is very small and may even be zero. Strange concepts that cause conceptual difficulties. It is much easier for those with a good bit of quantum mechanics and general relativity under their belts. If you want to talk about it off line, let's give it a whirl.

The twirly polarization signal is probably only produced by an interaction between the gravity waves and the electromagnetic field. It has to do with the nature of the gravitational field and a property called spin, which is a bit abstract. But the bottom line is this is the only explanation that makes sense and the theoretical prediction is observed n Nature.

The term singularity doesn't have any scientific meaning. When you wind time backwards and extrapolate to the beginning of the Universe, you get zero size and infinite energy density at the moment of the Big Bang. This is unphysical and there is good evidence for something else - the stuff that seeded inflation. So if someone uses the term 'singularity' it is likely they aren't a physicist or astrophysicist.

It sort of makes sense to refer to the inflationary period as a huge hot explosion, except the explosion isn't expanding into space, but rather it is a pure expansion that is *creating* space. The distances between objects are expanding extremely rapidly - much faster than the speed of light. The objects themselves are not moving ... just the space between them is growing exponentially.

Real science is much more interesting that the best fiction human minds can dream up. Nature can be really weird by our standards:-)

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