Comments on: A Busy Couple of Weeks

By: shantanu

shantanu — Wed, 03 May 2006 03:37:25 +0000

Thanks, Sean for the answer . I find it difficult to intute stuff from Lagrangians, (but that’s just me.)
Also one more general quesion about all these modifed gravity
theories used to explain dark energy such
as DGP, CDTT and even those which are used to explain away dark matter
such as MOND/TeVss . Won’t these theories also affect physics of compact
objects such as neutron stars , black holes with possibly
some observable consequences which could be tested? (or the physics for such compact objects same as GR for thse modified gravity theories.) I haven’t seen any of these theories address physics of compact objects. But perhaps you or others could clarify.
Thanks

By: Sean

Sean — Tue, 18 Apr 2006 01:43:33 +0000

Sorry, Shantanu, I missed your question earlier. No, these theories generally do not obey the strong equivalence principle, since the behavior of gravity depends on the background; they are much like Brans-Dicke theories that way. But really it’s better to forget about the equivalence principle and think about Lagrangians.

By: Shantanu

Shantanu — Tue, 18 Apr 2006 01:37:20 +0000

Mark or Sean, could you tell me what is the answer to question # 10?
Thanks

By: Shantanu

Shantanu — Sat, 15 Apr 2006 08:00:45 +0000

Hi
I went through the transparencies of your talk at FNAL . I have a naive question.
(which I am sure is discussed in some of your papers) you cited.
the class of modified gravity models which you are considering
to account for Dark energy(eg CDTT) and that in astro-ph/0410031 , do these models obey strong equivalence principle?

By: Jim Graber

Jim Graber — Mon, 06 Mar 2006 22:15:37 +0000

Hopefully some ppt or pdf of your talk will soon be available on this website
http://www-ppd.fnal.gov/EPPOffice-w/colloq/colloq.html
or elsewhere?
Congratulations to your friends on their weddings etc. but I would really like to see some physics after this tantalizing hint.
Best,
Jim

By: Life is LIke a Box of

Life is LIke a Box of — Mon, 06 Mar 2006 21:27:34 +0000

Pick one. Sure. It doesn’t matter.

Nothing emotional about the future of cosmology and of physics of reductionism together?

Okay. So you don’t get emotionally involved.

It’s still science.

And that’s all I got to say about that.

By: Science

Science — Mon, 06 Mar 2006 21:04:34 +0000

I just mean LQG. Greene is prejudiced in favour of string theory, which is fine if he keeps scientific, but we don’t need emotional brainwashing to spread prejudice in science.

By: Plato

Plato — Mon, 06 Mar 2006 18:32:44 +0000

I wasn’t talking about all your other ideas:)

By: Science

Science — Mon, 06 Mar 2006 18:28:51 +0000

Plato: I disagree! If nature was inherently poetic and graceful, there would hardly be wars, starvation, disease, etc. People who write novels and film scripts are full of beautiful ideas and happy endings. The world simply isn’t like that. Don’t try to force your poetry on to natural science. High expectations create prejudices, and scientists have to be prepared to accept the most simple theory that explains the facts, even if it looks vulgar.

By: Plato

Plato — Mon, 06 Mar 2006 18:11:38 +0000

“Nothing to me would be more poetic; no outcome would be more graceful … than for us to confirm our theories of the ultramicroscopic makeup of spacetime and matter by turning our giant telescopes skyward and gazing at the stars,” Greene said.

You don’t have to be from any particluar “camp” to understand the implications of these words, without assigning them to some agenda?

By: Plato

Plato — Mon, 06 Mar 2006 15:09:12 +0000

Hey Count, And maybe a few modifications with that same future? "If it was possible to become free of negative emotions by a riskless implementation of an electrode - without impairing intelligence and the critical mind - I would be the first patient." Dalai Lama (Society for Neuroscience Congress, Nov. 2005) As I mentioned elsewhere, Iscap is a idea whose time has come, and recognition of the micropespective world, now joined with the cosmological understanding. As a layman, there is nothng more exciting then seeing this unification taking place. In what, we can percieve in the immediate environs, given the understanding, that this process of reductionism, can be reduced, and moved to the grand scheme of relativity? That, from natural processes, associative cosmological happenings, from collider experience. No sense linking here if one is not ready to explore the possibility of "new physics?" Ready to look at cosmology, with an all inclusive "geometric perspective," whatever this may be? We needed to understand the physics involved, and if you didn't have this, sure we'll just ponder geometric relations, without ever making them inclusive?

By: Count Iblis

Count Iblis — Mon, 06 Mar 2006 13:57:43 +0000

Mark, in the near future it will be easier to blog for you see here. All you have to do is think about it and the posting will appear on the blog.

By: Science

Science — Mon, 06 Mar 2006 09:53:37 +0000

Mark, that question about connecting cosmic acceleration and gravity is very interesting. Quantum field theory experts I know a little seem to be (almost) proud to say they know little about cosmology (beyond nuclear reactions in the first 3 minutes). However, as Eddington said, the ratio of electromagnetic to gravitational force is a “cosmological” sized number…