Making Sense of Modern Cosmology

Editor’s Note (10/9/19): Cosmologist James Peebles won a 2019 Nobel Prize in Physics for his contributions to theories of how our universe began and evolved. He describes the latest ideas in cosmology in this article he wrote for Scientific American in 2001.

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Tau.Neutrino said:

Making Sense of Modern Cosmology

Editor’s Note (10/9/19): Cosmologist James Peebles won a 2019 Nobel Prize in Physics for his contributions to theories of how our universe began and evolved. He describes the latest ideas in cosmology in this article he wrote for Scientific American in 2001.

more…

I have a book called “modern cosmology” on my bookshelf. https://www.amazon.co.uk/Modern-Cosmology-Pelican-Jagjit-Singh/dp/0140210601 It was written in 1970. Good book.

Cripes, what a cynic. All five of those should have an A+ rating. They’re all true.

Tau.Neutrino said:

Making Sense of Modern Cosmology

Editor’s Note (10/9/19): Cosmologist James Peebles won a 2019 Nobel Prize in Physics for his contributions to theories of how our universe began and evolved. He describes the latest ideas in cosmology in this article he wrote for Scientific American in 2001.

more…

Looks worth a read; I’ll come back at morning tea :)

(It should be noted that the actual article was written in 2001).

mollwollfumble said:

Tau.Neutrino said:

Making Sense of Modern Cosmology

Editor’s Note (10/9/19): Cosmologist James Peebles won a 2019 Nobel Prize in Physics for his contributions to theories of how our universe began and evolved. He describes the latest ideas in cosmology in this article he wrote for Scientific American in 2001.

more…

I have a book called “modern cosmology” on my bookshelf. https://www.amazon.co.uk/Modern-Cosmology-Pelican-Jagjit-Singh/dp/0140210601 It was written in 1970. Good book.

Cripes, what a cynic. All five of those should have an A+ rating. They’re all true.

We don’t actually know that any of them are true.

The ratings still look reasonable to me.

The Rev Dodgson said:

mollwollfumble said:

Tau.Neutrino said:

Making Sense of Modern Cosmology

Editor’s Note (10/9/19): Cosmologist James Peebles won a 2019 Nobel Prize in Physics for his contributions to theories of how our universe began and evolved. He describes the latest ideas in cosmology in this article he wrote for Scientific American in 2001.

more…

I have a book called “modern cosmology” on my bookshelf. https://www.amazon.co.uk/Modern-Cosmology-Pelican-Jagjit-Singh/dp/0140210601 It was written in 1970. Good book.

Cripes, what a cynic. All five of those should have an A+ rating. They’re all true.

We don’t actually know that any of them are true.

The ratings still look reasonable to me.

Sort of, but Inflation deserves at least a B+. In order to solve the flatness problem (ie. the uniformity of the CMB), the early universe had to expand faster than the speed of light. So either the universe expanded really quickly (cosmic inflation) or the speed of light was much slower. The hypothesis that the speed of light was much slower looks very sick (it fails to explain the ripples in the CMB power spectrum for starters). So inflation has to be true.

mollwollfumble said:

Sort of, but Inflation deserves at least a B+. In order to solve the flatness problem (ie. the uniformity of the CMB), the early universe had to expand faster than the speed of light. So either the universe expanded really quickly (cosmic inflation) or the speed of light was much slower. The hypothesis that the speed of light was much slower looks very sick (it fails to explain the ripples in the CMB power spectrum for starters). So inflation has to be true.

I still don’t get why everybody talks about expansion of space, when shrinking of matter would seem to explain the same effects.

Also we know that quantum entanglement effects are transmitted instantaneously, or at least faster than we can measure, so I’m not that convinced that information can’t travel faster than light either.

The Rev Dodgson said:

mollwollfumble said:

Sort of, but Inflation deserves at least a B+. In order to solve the flatness problem (ie. the uniformity of the CMB), the early universe had to expand faster than the speed of light. So either the universe expanded really quickly (cosmic inflation) or the speed of light was much slower. The hypothesis that the speed of light was much slower looks very sick (it fails to explain the ripples in the CMB power spectrum for starters). So inflation has to be true.

I still don’t get why everybody talks about expansion of space, when shrinking of matter would seem to explain the same effects.

Also we know that quantum entanglement effects are transmitted instantaneously, or at least faster than we can measure, so I’m not that convinced that information can’t travel faster than light either.

Shrinking of matter won’t do, because we’re talking about epochs here before baryonic matter existed. Certainly long before the first neutron.

As for quantum effects, good pont, i hadn’t thought of that one.

Inflation is not just about expansion of space but of everything in it, i.e. space expands while maintaining its energy density.

Bubblecar said:

Inflation is not just about expansion of space but of everything in it, i.e. space expands while maintaining its energy density.

Are you sure about that?

The Rev Dodgson said:

Bubblecar said:

Inflation is not just about expansion of space but of everything in it, i.e. space expands while maintaining its energy density.

Are you sure about that?

That was what the theory was all about, last time I looked :)

Hence the expression “the universe is a free lunch”.