“. . . although our Earth is silicon-rich, other earths may instead be carbon-rich, like giant versions of carbon-rich asteroids and comets. Rather than silicate rocks, they’d have carbonaceous ones. In fact, [Jade] Bond [of the University of Arizona] suggests that such Earths may be the majority: most stars with planets contain proportionately more carbon than our sun does. Yet scientists have barely begun to think about how their geology would differ. ‘No one has looked at it,’ Bond says.”
Reporting each day for Scientific American, George Musser has relayed five brief but interesting updates on the proceedings of the American Astronomical Society’s Division of Planetary Sciences last week in Fajardo, Puerto Rico. The first update included Bond’s discussion of exoplanet characteristics from the which the preceding quote was excerpted, along with a review of Jupiter’s atmosphere, an update on Messenger’s most recent flyby of Mercury, and the geology of Saturn’s remarkable moon Titan.
The second update focused entirely upon undulations recently discovered in Saturn’s C ring – a more important discovery, perhaps, than the far more publicized discovery of Saturn’s new ring (Look here and
here for more about that.). You’ll find a more extensive discussion of the perturbation of Saturn’s rings What Shook Up Saturn’s Rings? in New Scientist.
Update three discussed planetary bombardments and asteroids, update four the LCROSS lunar impact and planetary formation, while update five concentrated on the unusual characteristics of Quaoar, the Kuiper Belt object discovered in 2002. Much further than Pluto (about 42 Astronomical Units from the sun), Quaoar has a greater density and a much less eccentric orbit. Why?