Intrinsic Alignments

Finished a measurement of intrinsic alignments

in clusters. Used Berlind's spectroscopic clusters

sample cross correlated with the main sample. I'm

getting a fairly weak bound (no detection), but this is

the first such measurement in clusters that I know of.

This shear needs to be converted to "delta sigma" as

measured for the clusters and I have done this.

Talks

Lots of talks here this week. Two 1.5 hour talks by

Leonard Susskind and a talk by Roger Penrose, plus

a job talk by Andrew Zentner and Alice Shapley is

talking tomorrow.

Susskind and Penrose both talked about things we

don't understand. Susskind discussed, for example,

how everyone loves the eternal inflation, bubble

nucleation, pocket universe theory, but at this point

its just a neat idea with no conceptual or mathematical

foundation. He tried to show that there are indications

that there might exist such a foundation.

Penrose talked about what happened before the big bang.

All the math breaks down there both classically and

the best quantum efforts, so you have to come up with

something new. His talk centered around the concept

that, at a nearly infinite time from now when lambda has

accelerated everything away and if all particles have decayed

away and black holes have evaporated, and somehow you

could get rid of electrons too, then there would be only

photons in the universe. In that case time has no meaning

at all since photons don't experience times. You can't build

clocks. This is an interesting idea. But then he made a huge

leap and said that if suddenly the phase space is rescaled so that

it appears to be a very dense universe, then it looks

like the big bang and everything starts over again.

Erin

## Thursday, April 13, 2006

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