Classifying Planets

Classifying Planets

This year’s Masursky Lecture is being given by Alan Stern. Stern seriously earned my respect last year in the face of a disgruntled room of geophysicists who didn’t have the nuclear engines they needed, who’d been told that Mars was not a funding priority, and who had been saddled with manned moon plans. He handled them all with respect and then left NASA the very next week. I’m glad the world of science has grabbed him back from the clutches of administration. His talk focused on who planets are defined and classified. As we gear up for this summer’s IAU General Assembly, many folks are wondering if (hoping really) they will clarify what is and is not a planet. As a starting point he explained that the discussion originated from the...

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And it came from the CMB . . .

And it came from the CMB . . .

wmap_skymap.jpgFraser (my co-host over at Astronomy Cast) and I like to joke about how everything we know in astronomy we know because of the Cosmic Microwave Background. How do we know the universe formed during the Big Bang? The CMB. How do we know the cosmic geometry is flat? The CMB. How do we know the mass distribution of the Oort Cloud? The CMB. How do we know where babies come from? The CMB.

Okay, so that last one is an exaggeration. As far as I know, human babies and the CMB have nothing in common. The remark about the Oort Cloud, however, may not always be as far fetched as it sounds. A group of scientists working at the Harvard-Smithsonian Center for Astrophysics, and lead by David Babich, have theorized a new technique for determining the mass distribution in the Oort cloud using distortions in the Cosmic Microwave Background.

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Flying Metal Bits

Flying Metal Bits

corot.jpgA quick fly through the nearby universe will show you, well, a whole lot of nothing. But, embedded in the nearest bits of that nothing are 8 spectacular planets, dozens of moons, and hundreds of random bits of rock and ice that, depending on where they orbit, fall into such categories as asteroids, Kuiper belt objects, and comets. Somewhat randomly distributed around (and sometimes on) these celestial objects are little bits of flying metal.

Locally, COROT (vaguely rhymes with Inspector Perot), obtained first light today (image above, credit CNES 2006 – D. Ducros). This orbital observatory will dedicate it self to the search for rocky worlds around other stars. A product of the European Space Agency, COROT will study nearby stars with its 30cm telescope, looking for slight changes in brightness indicative of planetary transits. The images it takes will also be useful for asteroseismology, the study of how stars bump and wiggle in reaction to chemical and thermal processes deep beneath their surfaces. Pre-launch calculations predict that every 150 days (the time COROT will spend studying one area of the sky), COROT could discover 10-40 rocky planets and tens of gas giants. Since the first published discoveries of an extrasolar planet around a pulsar in 1992, and around a normal star in 1995, astronomers have only discovered 209 extrasolar worlds. With COROT, that number could double in as little as 1 year.

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