Outer Solar System

New Work on Dwarf Planet 2007 OR10

May 17, 2016

Although we always think of Kepler — and its successor mission K2 — as an exoplanet observatory, the spacecraft has also been put to work on objects much closer to home. Enter 2007 OR10, a dwarf planet that is currently about twice as distant from the Sun as Pluto. The Kepler instrument is, of course, […]

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Pluto: Unusual Interactions with the Solar Wind

May 5, 2016

David McComas (Princeton University) calls what his team of researchers have learned about the solar wind at Pluto ‘astonishing,’ adding “This is a type of interaction we’ve never seen before anywhere in our Solar System.” The reference is to data from the Solar Wind Around Pluto (SWAP) instrument that flew aboard New Horizons. McComas knows […]

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Beneath a Methane Sea

April 27, 2016

Back when Cassini was approaching Saturn and we all anticipated the arrival of the Huygens payload on the surface, speculation grew that rather than finding a solid surface, Huygens might ‘splash down’ in a hydrocarbon sea. I can remember art to that effect in various Internet venues of the time. In the event, Huygens came […]

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Of a Mountain on Titan

March 29, 2016

If Saturn’s inner moons are, as we discussed yesterday, as ‘young’ as the Cretaceous, then we have much to think about in terms of possible astrobiology there. But Titan is unaffected by the model put forward by Drs. Ćuk, Dones and Nesvorný, being beyond the range of these complex interactions. Huge, possessed of fascinating weather […]

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Saturn’s Moons: A Question of Age

March 28, 2016

Some years back at a Princeton conference I had the pleasure of hearing Richard Gott discussing the age of Saturn’s rings. Gott is the author of, in addition to much else, Time Travel in Einstein’s Universe (Houghton Mifflin, 2001). I admit the question of Saturn’s rings had never occurred to me, my assumption being that […]

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What Ceres’ Bright Spots Can Tell Us

March 16, 2016

Garrett P. Serviss was a writer whose name has been obscured by time, but in his day, which would be the late 19th and early 20th Century, he was esteemed as a popularizer of astronomy. He began with the New York Sun but went on to write fifteen books, eight of which focused on the […]

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Charon: Evidence of an Ancient Ocean

February 22, 2016

I will admit to a fascination with Pluto’s moon Charon that began even before it was discovered. Intrigued by the most distant places in the Solar System, I had always imagined what the view would be like from a tiny moon circling Pluto. At the time, we didn’t know about Charon, so my vantage point […]

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Saying Goodbye to Philae

February 15, 2016

Landing on a small object in the Solar System isn’t easy. Witness the Philae lander, which traveled to Comet 67P/Churyumov-Gerasimenko as part of the European Space Agency’s Rosetta mission. Philae ‘landed’ on November 12, 2014, having to deal with a malfunctioning thruster along the way. Upon arrival at the surface of the comet, Philae was […]

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Probing the Interior of a Comet

February 8, 2016

Knowing what comets are made of — dust and ice — only begins to answer the mystery of what is inside them. A compact object with this composition should be heavier than water, but we know that many comets have densities much lower than that of water ice. The implication is that comets are porous, […]

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The Distant Thing Imagined

February 5, 2016

If there’s one thing Pluto turned out to have beyond all expectation, it’s geological activity. New Horizons is now showing us what researchers are calling ‘hills of water ice’ floating in a sea of frozen nitrogen, much like icebergs moving through our own Arctic Ocean. The isolated hills are thought to be fragments of the […]

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