Friday, 16 January 2009 by lukemeister.

NASA held an interesting press conference yesterday about the discovery of localized emissions of methane from Mars. The discovery of Martian methane, using both ground-based telescopes and a spacecraft orbiting Mars, was reported in 2003, but the detections weren’t certain. Now high-resolution infrared spectra taken by Michael Mumma at NASA/Goddard and colleagues, reported online in Science, seems to provide definitive measurements. The CH₄ appears to arise from three regions near or within Arabia Terra, Nili Fossae, and Syrtis Major. The most intriguing observation in the new study is that the atmospheric abundance of methane dropped by a factor of two between 2003 (northern summer on Mars) and 2006 (vernal equinox on Mars), possibly suggesting a seasonal cycle. Methane has a lifetime of centuries against destruction by ultraviolet light from the Sun, so there must be another sink, possibly involving reactions with perchlorate or peroxide in the Martian soil.

On Earth most methane is generally thought to originate biologically, although it can also be produced through serpentinization, which involves the reaction of minerals like olivine and pyroxene with water and carbon dioxide. Both biological and abiological origins for Mars’ methane are in play. If martian microbes exist, their metabolism might resemble that of organisms found at 3 km depth in a gold mine in South Africa. Even if Martian methane originates abiologically, the new observations seem to imply that Mars shows a surprisingly high level of geological activity, as serpentinization on Earth is associated with hydrothermal systems.

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Sunday, 3 August 2008 by lukemeister.

For the last 12 days, I’ve been with my wife, son, and sister-in-law attending Cassini workshops in Paris and London. We tried to go to the Catacombs in Paris but arrived too late. In London I got a second chance to contemplate mortality, because the Wellcome Trust, which funds biomedical research in the UK, currently has 27 skeletons on display, selected from the 17,000 that the Museum of London has in storage. The skeletons on view range in age from Roman times to the 19th century, and were found during routine construction projects. Not being a fan of forensics shows on TV, I had naively thought that skeletons were reasonably impervious to the insults of life, but even I could see the holes in the bones of the man from Roman times with multiple myeloma and the horribly disfigured skull of an 11-year-old boy, ca. 15th century, born with syphilis. I was moved by the skeleton of a young woman with the bones of her 24-weeks’-gestation child still in her pelvis.

Yesterday I saw the Hadrian exhibit at the British Museum, which has gotten a lot of hype. Hadrian is considered one of the greatest emperors of Rome, although I’m not sure why. He quickly abandoned the eastern provinces conquered by Trajan and crushed a Jewish revolt. He did love Greek culture, and one Greek in particular. For a while, the cult of Antinous competed successfully with Christianity, a fact I don’t recall Mr. Babel mentioning in 9th grade Ancient History class. Of course, the Wall was built during Hadrian’s reign to keep those pesky Picts out of Britannia. Mostly what I learned was that even for so famous a figure, much of what has come down to us was written at least two centuries later, and its veracity is disputed. Hadrian wrote an autobiography, but it is lost. Just last year an impressive statue of Hadrian was unearthed in Turkey, and is part of the display in London. Also on display were five Roman funerary portraits from Egypt, which are very moving. Many were used by their finders to build fires, but fortunately some 1,000 survive. They look amazingly fresh.

On an unrelated note, Christine and I saw West Side Story tonight, our last night in London. The idea of seeing an iconic American musical in England first seemed absurd to me, but the play was spectacular, better than even the terrific performance of Cabaret starring Anna Maxwell Martin that we saw two years ago. West Side Story has as much of a happy ending as one can hope for these days.

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