Engineering Colloquium Home
Schedule for this lecture.
Goddard Space Flight Center Engineering Colloquium
Date: Monday, March 23, 1998
The Microwave Anisotropy Probe, NASA'S second Midex mission, is designed to take another major step toward understanding the universe we live in. The highly successful COBE mission pioneered space measurements of the Cosmic Microwave Background Radiation (CMBR) and showed conclusively that "space is the place" to make such measurements. COBE's small antennas could not reach angular scales below 7 degrees, but most cosmological models predict interesting wiggles in the angular power spectrum at 1 degree and smaller. If the MAP results can be fit to a plausible cosmological model, we will learn about detailed physical conditions in the universe when it was in its infancy, an age of 300,000 years, and measure some important cosmological parameters. The talk will start with a brief review of how one thinks about the universe we live in. It's a strange place. There is no center, better yet, the center is everywhere. The Big Bang event is on a spherical shell (15 billion light years in radius) with us at the center. That's because the speed of light is finite. Our universe is contained in a causal bubble whose surface is expanding at the speed of light into a yet unseen "super universe" which was all part of the Big Bang. I said it is strange.
After doing a PhD Thesis at Michigan with H. R. Crane, measuring g--2 for the free electron, Dr. Wilkinson went to Princeton to do gravitation research with R. H. Dicke. At Dicke's suggestion, Wilkinson and Dicke worked out the numbers and drafted a paper pointing out that laser ranging to corner reflectors on the moon could measure the Earth-Moon distance with an accuracy of a few centimeters. Thanks to NASA's Apollo project, this is now being done routinely. Another of Dicke's good ideas was to look for the cosmic microwave background radiation that ought to be left over from a Hot Big Bang. Dr Wilkinson has spent the last 35 years measuring the spectrum and anisotropy of this radiation with many students and colleagues. Twenty-five years ago it became abundantly clear that a satellite experiment was needed to get high enough accuracy to look for interesting effects predicted by the Big Bang cosmological model. The COBE satellite was invented by a small group brought together by John Mather. Launched in 1989, COBE was a remarkable success, verifying the Hot Big Bang model and discovering anisotropy in the cosmic microwave background radiation. Seven years ago, Princeton colleagues and Dr. Wilkinson proposed a mission concept to NASA for following up on the COBE success with a satellite to measure the anisotropy at higher angular resolution. The current MAP satellite is a much improved version of that design.
Colloquium Committee Sponsor: Eugene Waluschka
Engineering Colloquium home page: https://ecolloq.gsfc.nasa.gov