Archive for September, 2008


Monday, September 15th, 2008

Since I went after after Gregg Easterbrook for promoting intelligent design, Matt Trawick suggested that I should link to a couple of the good things he’s written about NASA and the space shuttle program. Here are a few examples.

Recently, Easterbrook has explained why plans for a lunar base make no sense. He wrote more broadly about NASA’s misplaced priorities for human space flight. He’s been a big space-shuttle skeptic since at least 1980.

I thought that he was the one who coined the phrase “billion-dollar flagpole sitting” to describe our recent priorities on human space flight, but I can’t find confirmation of that.

Teach the controversy

Monday, September 15th, 2008

Matt Trawick’s comments on my earlier post on Gregg Easterbrook and “teaching the controversy” are exactly right.  I’ll just add that the seeming reasonableness of the “teach the controversy” position are precisely what makes it so pernicious.

Some people address this with humor.  I sometimes find this approach very funny, but of course it’s of no value at all for actually convincing people who aren’t already convinced.

If you want actual evidence, there’s this survey of biology department heads, which found that essentially none thought that there was a controvery.  I found this at the National Center for Science Education,  which has a lot of resources promoting the teaching of evolution.

Black holes in Slate

Wednesday, September 10th, 2008

The online magazine Slate published a piece today explaining what happens to you if you fall into a black hole, and they had the good sense to consult me on it. Slate’s “Explainer” articles are also podcasted, so if you’re not into reading, you can listen to it instead.

The article pretty much gets things right. One minor quibble: the sentence

In fact, for all but the largest black holes, dissolution would happen before a person even crossed the event horizon, and it would take place in a matter of billionths of a second.

isn’t quite right: the “billionths of a second” number (which I think the author got from me) applies only to quite small black holes, not to “all but the largest” ones, and I think that even for stellar-mass black holes (which are much smaller than “the largest” ones) you’d make it across the horizon before being ripped apart by tidal forces. But those are pretty minor points; the main ideas are all right.

The motivation for this article is the possibility that the Large Hadron Collider will produce black holes. Short answer: It probably won’t, and even if it does, they’ll evaporate quickly rather than gobbling up the Earth. You really don’t need to worry about this.

Slate doesn’t do a lot of science reporting, but when they do it’s often pretty good. A recent article discussed one of the main things the LHC is actually expected to find, namely evidence for the Higgs mechanism. Unlike a lot of writing on the subject, this article actually tried to explain the fact that the Higgs mechanism won’t necessarily manifest itself as just a single new type of particle: it’s likely that something more complicated will be found. If so, that’ll be much more interesting than just finding a single Higgs particle.

Since I’ve been saying nice things about Slate, I want to end with one criticism of their science reporting: they still let Gregg Easterbrook write about science from time to time. Easterbrook’s done some good stuff over the years — in particular he was sharply and rightly critical of the space shuttle and space station long before that became fashionable, and he deserves credit for publicly and forthrightly changing his mind about global warming. (Also, I’ve heard his writing on the NFL is good, but I know nothing about that.) But as far as I’m concerned, anyone who defends the teaching of intelligent design in science classes forfeits all credibility as a science journalist. Yes, I’m intolerant and closed-minded about this. But I’m also right, so it’s OK.

Black holes

Thursday, September 4th, 2008

The section of my Black Hole FAQ on the observational evidence for black holes is sadly out of date, although the rest of it is still reasonably current. I don’t have any plans to update it, because that sounds altogether too much like work. I’d have to read a lot about things I don’t know much about in order to get up to speed on the subject, and if I’m going to do that, I think it’d be more fun to do it on some new subject rather than revisiting this one.

If I were going to write about this subject, though, I’d certainly want to talk about some recent results published in Nature concerning observations of the black hole at the center of our Galaxy. I think you need to be a subscriber to see the article or Nature’s newsy description of it, but there’s a Science News article that I think is publicly available. (Thanks to my brother Andy for pointing this out to me.)

There’s no way to see past the horizon of a black hole, so the name of the game in this business is to try to see as close as you can to the horizon. If you can resolve details near the horizon, you can look for distorting effects due to gravity, which provide pretty definite evidence that what you’re looking at really is a black hole. If all you can see is stuff that’s 1000 times bigger than the horizon, then it’s hard to tell the difference between a black hole and any other object of the same mass. The authors of this paper have managed to resolve structures that are just about the same size as the horizon.

By the way, one of the authors was a friend of mine in graduate school. Among his lesser-known accomplishments is writing a brochure describing the Berkeley astronomy department to incoming graduate students, in the form of Allen Ginsberg’s “Howl”. I don’t know if copies of it survive, unfortunately.