2013 — 10 August: Saturday
As a fully-paid-up member1 I'm always pleased to discover some new (to me) factoid or opinion about "Oppy", particularly before breakfast on a sunny morning (despite its unfashionable coolness). So, wrap your head round this little gem:
Karl Hufbauer contributes a chapter, "J. Robert Oppenheimer's Path to Black Holes," discussing what I consider the outstanding mystery of Oppenheimer's life. In 1939 Oppenheimer
published with his student Hartland Snyder a paper, "On Continued Gravitational Contraction," only four pages long, which is in my opinion Oppenheimer's one and only revolutionary
contribution to science. In that paper, Oppenheimer and Snyder invented2 the concept of black holes; they proved that every star significantly
more massive than the sun must end its life as a black hole, and deduced that black holes must exist as real objects in the sky around us. They showed that Einstein's theory of general
relativity compels any massive star that has exhausted its supply of nuclear fuel to enter a state of permanent free fall. Permanent free fall was a new idea, counterintuitive and
profoundly important. It allows a massive star to keep falling permanently into a black hole without ever reaching the bottom.
Einstein never imagined and never accepted this consequence of his theory. Oppenheimer imagined it and accepted it.
The fact that this extract comes from the section of his review wherein Dyson reminds us that Monk has overlooked a key book of Centennial essays merely adds another layer of mystery to all the other mysteries of Oppenheimer's fascinating life. Let alone to that of gravitation, which is a whole different can of worms (or, maybe, wormholes). For example, Dyson fails to mention the "highly idealized nature of the calculation" (which assumes the collapsing star to be perfectly spherical and nonrotating) pointed out by Begelman and Rees in "Gravity's Fatal Attraction". Physicists of the time were naturally only too happy to regard this as a fatal flaw. But within 30 years, Kerr (in 1963), and a few years later, Hawking and Penrose, had between them brought us the symmetrical and whimsically-named stationary "hairless" black hole.
Now back to what remains of Brian Matthew and some overdue asymmetrical breakfast to fill my own black hole.
Good grief!
Buying a "Choose Life" licence plate for your car in Virginia directs money to a so-called "Crisis Pregnancy Center" that then promulgates guff such as:
If you have an abortion, you will see that child's soul again in the future: "At the end of the world you're gonna know that was my child that I choose to kill."
That's Virginia off my list of places to wish to visit, let alone live in.
Too long...
... since I last watched this marvellous film:
Now here's a...
... very worrying thought: "Progress in understanding the chemical basis of behavior will make it increasingly untenable to retain a belief in the concept of free will," writes biologist Anthony R. Cashmore.
More here.
There was...
... yet another "40" limit being imposed on the south-bound motorway a few hours ago; at least I've now learned enough to watch out for the warning signs at the entrance in time to dodge3 rather than blithely assuming motorways are always free-running high-speed motoring delights. If they ever were. Which I strongly doubt.
I wonder...
... how many UK MPs can pass this test? I certainly can't!
Should I buy the Official Handbook, or simply emigrate? On the other hand... I'm not a citizen, I'm a subject. This is, after all, a monarchy rather than a democracy, is it not?