Thursday, May 08, 2003

Astrophysics. I started college as a math major, decided on physics when I noticed in my junior year that I only needed two more physics courses for a physics degree. I wasn't really into it until my senior year, when I had to do a thesis and started working with the OSO-7 X-ray astronomy group at the MIT Center for Space Research. This was the 2nd satellite put up to look at X-ray sources (X-rays don't get through the atmosphere). The rest of the group was working on galactic objects -- primarily collapsed objects (neutron stars and the 1st black hole candidates) particularly in eclipsing binary systems. I was put on extragalactic stuff, and I really fell in love with it. Extragalactic X-rays are mostly from hot gas in the central regions of rich clusters of galaxies, and, to a much lesser extent, from AGN (active galactic nuclei). It's really cool, with every different wavelength (x-ray, gamma, infrared, radio) different types of objects show up galactically and extragalactically.

OSO-7 wasn't really a very good instrument for extragalactic x-ray work (not precise enough), and I wasn't a great scientist. The one paper I published was the incorrect identification of an extragalactic x-ray source (with a solitary radio galaxy, 3C317 instead of a rich cluster A2029). Oh well. It was great tho, zooming out amongst the galaxy clusters, just like the Silver Surfer, and coming up with theories for all kinds of stuff.

Studying the clusters, I concluded that the ideas popular at the time about the size of galaxy superclusters were incorrect. They were mostly put at 10-20 Mpc (Mpc = megaparsec = 1 million parsecs, 1 parsec = ~3 light years), I had them at more like 100-200 Mpc. So, I was seeing the great walls, voids, and filaments that are now known about 15-20 years before they made the big time. The joys of pattern recognition.

Based on the form of the superclusters, I had my own cosmology! I borrowed the concept of "retarded cores" from the Russians -- retarded cores are basically white holes, left over pieces of the big bang, at the center of galaxies. My picture was a universe where the big bang was a big split, followed by another, etc ... So the white hole that is the big bang divides and redivides like a growing life form. The missing mass is left in the retarded cores, not yet emerged into the universe.

Unfortunately:

  1. The math doesn't work for white holes in our universe, according to something I read in Penrose years ago. Serious problems with entropy.
  2. Hubble (the Hubble space telescope) has pretty much confirmed the normal theories of galaxies: that they accrete from smaller pieces, and that AGN grow from stuff collecting in the gravitational well. Hubble is really amazing. For years, theorists were positing galactic centers with accretion disks and jets escaping via the magnetic poles -- then Hubble takes a picture of it in the center of M-87! (M-87 is the supergiant cD galaxy at the center of the Virgo Cluster.)
The only thing that I remember from then that I still wonder about was that there seemed to be an anomalous number of rich Abell clusters in pairs. Of course, I haven't kept up with the astrophysical journals since 1975, this may have already been studied and published. I would suspect that clusters are like galaxies and stars, and condense out (according to a power law?) 60% singles, 30% doubles, 10% higher groupings. Lots of the rich Abell clusters have paired galaxies at their center as well.

In spring of 1974, the OSO-7 funding ran out. My boss said that he could get me on the next project (I was basically working in a postdoc position for that wonderful postdoc money), but that if I wanted to stay in the field, I should get my doctorate, etc. I applied to MIT grad school, but my grades were mediocre enough that they wanted me to take a grad course and ace it before they would admit me. Around that time, I met the brightest young astrophysicist in the world (I don't remember his name) when he presented a session at MIT. I was totally up on the literature at the time, and this guy had published really original stuff in 3 or 4 different areas -- unheard of. Anyway, I was talking to him, and he was in his 3rd or 4th year of postdoc, still trying to find an entry level position somewhere. I decided I didn't want to live my life hanging on the whim of congress and the NSF, and moved back to Louisville to look for work.

I still get Sky and Telescope, which does a fairly decent job in keeping up on astronomy and astrophysics. I taught a lot of the constellations to my younger two daughters. But, leaving astrophysics is probably the main thing I look back on in my life and experience a retroactive "urge to clone". But, as I tell my kids, all of life is about making decisions that prune branches from the possibility space of your future. The branches I have wound up in have been fine.

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