Thursday, February 22, 2007

Dark Energy as an Environmental Science?!


Atrium of San Francisco's Museum of Modern Art. The huge SF Hilton was filled past the bursting point by AAAS, with additional events spilling over to the Nikko and Parc 55 hotels. One of the most crowded spaces was Franciscan Room C on Sunday afternoon. The seminar was titled: "Multiverses, Dark Energy and Physics as an Environmental Science." Despite the confusion and lack of answers, the crowd size hows how much interest is out there.

Lawrence Krauss intoduced the session as: "Why Scientists Have Gone Mad." He reviewed the same old evidence for inflation and "dark energy" with a very skeptical eye. He emphasised that current cosmology is observation-driven rather than theory-driven. Regarding supernova data, he said it "naively implied that the universe was accelerating."

According to the "dark energy" idea, the era of cosmic structure formation is over. The facts that stars continue to form, galaxies collide and life builds complex structures ought to sink that idea. Alain Blanchard's team has observed that there are even more clusters forming in our era, when DE is supposed to have taken over. The evidence is overwhelmingly against a repulsive energy.

Introducing Lenny Susskind, the term "sinking ship" arose in regards to strings. Lenny was good-natured as always, and giving an entertaining talk on the landscape. Andrei Linde's talk finished the session by calling strings an "eternal feast" with 10^1000 vacua! Rather than seeing the glass as empty, Linde and others think this is a benefit. (Disclaimer: Susskind gave this author an A in a theoretical physics course.)

The theme of this year's AAAS Meeting was "Science and Technology for a Sustainable Well-Being." Despite the session title, there was no attempt to connect strings or cosmology to the environment. Though the Supernova Cosmology Project is right across the Bay in Berkeley, no "dark energy" researchers spoke at the session. The job of promoting DE was left to senior people like Steven Chu and Burt Richter. Even if strings or DE exist, they have no possible use for improving the environment or our energy problems.

A cosmology with a changing speed of light has direct bearing on our environment. It solves the "Faint Young Sun" paradox of Earth's temperature, telling us whether that temperature will grow uncontrollably. Cosmology also contributes to the question of whether greenhouse gases warmed Earth in the past. Including Type Ia supernovae, we have corroborating data from truly independent sources indicating that c has changed in precisely the amounts predicted. It may someday lead to an energy source even greater than nuclear fusion.

Sunday night was a reception for the Association of Women in Science. Every year more young women show up at the AAAS Meeting. Sometimes they come in groups, encouraged by their schools or colleges. We were supposed to be addressed by San Francisco's mayor, but he has cut public appearances and gone into seclusion. Gavin, if you had shown up you would have met many attractive, intelligent women.

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5 Comments:

Blogger nige said...

Thanks for this report. It's interesting that you studied under Professor Susskind.

Do you happen to know if he generally interested in ideas outside his own (very slightly speculative) multiverse?

9:54 AM  
Blogger L. Riofrio said...

HI nige! In class, Lenny lectures about quantum theory, Relativity and other accepted ideas, with a few asides to his own "landscape" ideas. He also writes and lectures about the landscape. I've not approached him with my own theories, for he has a full plate already.

10:05 AM  
Anonymous Anonymous said...

Hi Louise,

I have a question about high Z astronomical observations.

Since the early universe was more dense (on average) than it is today, do observed redshifts (particularly at high Z) contain a gravitational component, as well as the more usual cosmological (expansion) component?

Thanks.

12:19 PM  
Blogger Rae Ann said...

That is probably exactly why Gavin didn't show up. ;-)

12:50 PM  
Blogger L. Riofrio said...

Anon, I hope this answers your question: High-z redshifts are caused by expansion of the Universe, which is in turn affected by gravitation. My own work indicates that redshifts are affected by a changing speed of light, making the Universe appear to accelerate.

Good one, Rae Ann! At least Gavin would have met intelligent women who weren't already married.

1:25 PM  

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