Are black holes racist? Science literacy in the US of A

A county commissioner meeting in Dallas County, Texas, erupts into uproar and accusations of racism after

Commissioner Kenneth Mayfield, who is white, said it seemed that central collections "has become a black hole" because paperwork reportedly has become lost in the office.

I kid you not. Read the article at the Dallas Daily News.

Speaking of scientific literacy, or the lack thereof, Razib at Gene Expression has an interesting set of posts exploring the results of a new survey of scientific literacy in the US population that allows for a detailed demographic breakdown, and comparison to other countries:

• The 18-24 year old demographic is, on some subjects, significantly more scientifically literate than the over 65 demographic, and the US isn't that terribly illiterate compared to other countries. Actually in some other tests of scientific literacy the US does really quite well. This seems like good news to me.
  
• However, church goers and those who identify themselves as Protestant or Catholic have lower than average levels of science literacy. This is hardly unexpected: members of more hard-line versions of Christianity also do worse in IQ tests and SAT tests. But living in the south, lower socio-economic status, or failing to graduate high school also have strong correlations with scientific illiteracy, and all of these things are linked.

100 years since the Tunguska Explosion

The Tunguska Explosion took place on June 30th 1908, exactly 100 years ago today. Although it is almost certain that it was the result of an small asteroid or comet exploding in the atmosphere with an estimated yield(*) equivalent to 20 million tons of TNT (i.e. over a thousand times more energy than released by the atomic bomb dropped on Hiroshima), many mysteries still remain.

Scientific American had an interesting article on Tunguska in its June 2008 edition, on the search for a crater. Space.com has another article worth a look, which has some fun at the end by mentioning some of the more outlandish hypotheses put forward over the years: an alien space ship blowing up, a mini-black hole passing through the Earth, or Tesla's experimental death ray.

(*) The explosion of 1 ton of TNT is equivalent to the release of 4.18e9 Joules of energy (see here), so roughly the Tunguska explosion was about 8.4e15 Joules, or 8.4e22 ergs. By way of comparison the luminosity of the Sun is 3.845e33 ergs per second.

[The image is of trees flattened by the explosion, taken twenty years afterwards by the Kulik expedition. Source: APOD for 2007 November 14]

A short history of nuclear-powered aircraft

Shaviv at DailyKos provides an interesting summary of the unhappy history of nuclear powered aircraft designs, featuring the Convair X-6, the XB-70 Valkyrie (very 70's looking, as you can see from the Wikimedia Commons image, but still a beautiful bit of technology), and the un-manned nuclear ramjet Project Pluto.

Is anyone currently thinking big and trying to make ambitious outside-the-box stuff like this?

More evidence for ancient impactor as sources of Mars's North/South dichotomy

A variety of media outlets are reporting on a series of new papers that strengthen the case that the peculiar differences between the northern and southern hemispheres of Mars (e.g. see this topographic map of Mars, or this web page) are due to a very large impact by a proto-planetary object of order 1000 miles in diameter.

Kenneth Chang discusses this in an article in the NYT, although he awkwardly calls the impactor a "meteor." Clara Moskowitz at Space.com also discusses the story, as does JR Minkle at SciAm news (see if you can spot the mistake in the image caption accompanying the SciAm article).

[Image shown is a color-coded map of the elevation of Mars, from the Mars Orbiter Laser Altimeter, showing the low, smooth, northern hemisphere and the higher, cratered, south. Note that even recently (1999) this data was used to argue against an external cause for the north/south dichotomy.]