Arcadian Functor

occasional meanderings in physics' brave new world

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Marni D. Sheppeard

Thursday, November 09, 2006

Dark Energy Epicycles

Over at CV Sean has a new post entitled Out-Einsteining Einstein. Alas, on trying to post a technical remark regarding Dark Matter I discovered that I have been banned from CV. This blog will just have to post a bit more on the subject now.

As is well known, Einstein thought the cosmological constant was a big mistake. The early solutions to his equations, without the constant, described expanding universes, but no one at that time had made any observations indicating that the universe was in fact expanding, and Einstein was horrified by a vision of the cosmos that went against all previous ideas. Eventually the constant was forgotten, except by a few die hard General Relativists who liked playing with the equations.

In 1998 an apparent (note this word) acceleration in the expansion was observed using Type IA supernovae, which act as standard candles due to the uniformity in their nature. In the Standard Cosmology, much other data appeared to confirm the assessment that the expansion was in fact accelerating. But in the last year or two it has become clear that the standard picture cannot fit the supernovae data. The word on the street has been that our understanding of the standard candles must be flawed. Funny then that they fit the data so well at the low z part of the curve.

Anyway, the Standard Cosmology is wrong. It is quite easy to explain away the apparent acceleration. In fact, some General Relativists have been doing just that using simple modifications of the standard picture. The true cosmology, however, is radically different, as is well known by the great cosmologist Louise Riofrio. It means thinking about a varying speed of light, at the very least, and I say that because it gets much, much more radical the more you look at it.

Amongst Quantum Gravitists it is well understood that the correct Background Independent unified theory will radically alter our conceptions of space and time. We are only in the early days of M theory, but we can see that a varying speed of light cosmology is probably inevitable. It also has the advantage of actually agreeing with the data.


Blogger CarlBrannen said...

Sorry to hear you've been banned from CV. May you take this as an influence to write up some of your results for arXiv instead.

Work progresses on the book. I had an artistic crisis when I realized that I had waaaay too many Kipling poems as compared to the number of chapters. I've solved the problem by cutting it up and making the chapters shorter. And more devoted to single topics.

November 09, 2006 2:05 PM  
Blogger Kea said...

I've solved the problem by cutting it up and making the chapters shorter.

Hee, hee. I know the quote problem! I have a lot in my thesis ... which I should be able to finish soon (along with a paper with Mike) if I stop blogging too much ...

November 09, 2006 2:27 PM  
Blogger CarlBrannen said...

My problem is I'm house sitting for a friend. He has internet access and TV. But I'm going to resist; put on headphones, and play Catherine Wheel, Toto, Depeche Mode, and RHCP until I get the next chapter out. Maybe I should go sabotage the internet connection...

November 09, 2006 5:39 PM  
Anonymous Anonymous said...

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November 10, 2006 1:01 PM  
Blogger Peter Fred said...

kea wrote
It is quite easy to explain away the apparent acceleration. It means thinking about a varying speed of light, at the very least....

If you find Louise's varying-the speed-of-light theory viable, I was wondering what think of my luminosity-based gravity theory where I argue that the universe started to accelerate 5 billion years ago (or fly apart more quickly) because the mean light output of the universe began to decrease about then.

January 22, 2007 5:27 AM  

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