Chapter IV of my dissertation was a joint project that I undertook in 1978 with my advisor, Professor Kip Thorne. Kip wanted to help jump-start gravitational-wave (GW) astronomy --- the study of the universe through direct observation of gravitational radiation. Since it's expensive and difficult to build GW detectors, any estimates of how much (or how little) a signal to expect is an aid. Kip proposed to examine common "Cherished Beliefs" about the cosmos, and to derive limits from those beliefs on what waves might be detected at various frequencies. I helped him compute and explore those implications. The original questions we addressed were posed by experimentalists Ronald Drever and Rainer Weiss.

The astrophysical cherished beliefs we assumed are quite straightforward and relatively uncontroversial:

In addition to these astronomical postulates, we relied on some simple and plausible cherished beliefs about the correct theory of gravitational waves:

The final paper that explored all this was titled "The Gravitational Waves That Bathe the Earth: Upper Limits Based on Theorists' Cherished Beliefs". It was dedicated to Abraham H. Taub, on the occasion of his retirement from the University of California at Berkeley, and appeared in a festschrift in honor of him published in 1980. Taub is a towering figure in relativity theory, whose work on ideal models of the universe (e.g., "Taub-NUT Space") is reputed to provide a counterexample to just about every common prejudice about cosmology. Kip knew Abe Taub personally as a colleague; I didn't have the privilege, though we met once or twice at seminars.

Our essay provided bounds on how strong gravitational waves might be at various frequencies for extragalactic and galactic sources, and for discrete objects --- bursters, transient sources, and continuous-wave monochromatic emitters --- as well as for an unresolved stochastic background. Thus far, no gravitational waves have been seen in confirmed experiments (though likely side-effects of waves are apparent in such systems as the Taylor-Hulse binary pulsar). Detectors are now becoming sensitive enough to get below our "cherished belief" limits. Perhaps some day soon!

(see KipTheDragon, RelativityPlusAstrophysics, NiAndMe, PulsarWaves, SoftOutsideCrunchyCenter, and SpinningSources for other ^z thesis work)

Wednesday, April 19, 2000 at 06:11:35 (EDT) = 2000-04-19

TopicPersonalHistory - TopicScience - TopicProfiles

(correlates: KipTheDragon, High Voltage Fiberoptic Cable, RelativityPlusAstrophysics, ...)