Aallegra.338 net.space utcsrgv!utzoo!decvax!ucbvax!npois!harpo!mhtsa!allegra!green Wed Mar 31 20:52:12 1982 Cosmic Microwave Anisotropy Today I heard a colloquium by Ed Cheng, a member of the Princeton group that has measured the anisotropy of the cosmic microwave background. The results so far can be summarized as follows: Three groups, Berkeley, Princeton, and Florence, have measured a dipole moment in the background. All three agree on this measurement. Of these groups, the first two have measurements covering enough of the sky to report on the quadrupole moment. These two groups disagree significantly on the quadropole moment. The difficulty in the quadrupole moment lies in the contribution of the galaxy. (The galaxy does not affect the dipole measurements because the dipole effect is relatively large and because the galaxy as viewed from here has little dipole moment). Errors in how the contribution of the galaxy are handled could explain the measured quadrupole moment. The final word on whether there is a quadrupole moment awaits more sensitive experiments. Leaving Ed's talk, I would like to comment on the fact that the microwave radiation does not establish an absolute or preferred rest frame, any more than does the earth or the sun or the galaxy. It is merely the rest frame of a larger object than any other object we have measured. Jim Green ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.