Saturday, September 17, 2005

Sir Hermann Bondi, 1919-2005

I first read of Hermann Bondi when I was about twelve, probably in George Gamow's One, Two, Three ... Infinity, a book that helped to convince me I wanted to be an astrophysicist. (It took Jane Reed, my Calculus I instructor, to dissuade me from this ambition.) Bondi, I learned, was one of a triumvirate of cosmologists (the others were Thomas Gold and Fred Hoyle) who championed the "steady state" theory of the universe. I later wondered how it came to be that a beach in Australia was named for him.

"Steady state" was posited in 1948 as an explanation for the condition of the universe as it was known at that time. Some years earlier, Edwin Hubble had shown that the universe is expanding. One possible reason was that it had started out very small, and exploded outward. This became known as the "big bang" theory. It implied that there was a finite amount of matter in the universe, and that, if the universe continued expanding, eventually it would become mostly empty, and dead. Alternatively, if there was sufficient matter that gravity would eventually overcome the expansive force, the universe would ultimately collapse back to the point from which it originated. Bondi, Gold and Hoyle, however, argued that, while the universe was expanding from a single point, matter is continuously being created at that point and expanding outward to replenish the void left behind earlier matter that had gone before it. Always has been, and always will.

Given that comparison, it seems that steady state is a much more optimistic theory than big bang. It's interesting, however, to consider that, in a way, steady state, which, according to the New York Times' obituary of Bondi today, "still has its adherents" (although evidence of residual microwave radiation from the big bang led Bondi himself to renounce it) is much more of a challenge to Biblical literalism even than Darwin's theory of evolution. After all, it squarely contradicts the first three words of Genesis, "In the beginning", positing, instead, that there was no beginning.

Bondi, who was born an Austrian Jew and emigrated to Britain when the Nazis occupied his homeland, had in common with many great British scientists a commitment to practical affairs along with theoretical work. He was among those who designed the Thames Barrier, which is meant to protect London from a disaster like that of New Orleans.