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Jupiter: Turmoil From Below, Battering From Above

October 18, 2012 Leave a comment

Jupiter, the mythical god of sky and thunder, would certainly be pleased at all the changes afoot at his namesake planet. As the planet gets peppered continually with small space rocks, wide belts of the atmosphere are changing color, hotspots are vanishing and reappearing, and clouds are gathering over one part of Jupiter, while dissipating over another. The results were presented today by Glenn Orton, a senior research scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., at the American Astronomical Society’s Division for Planetary Sciences Meeting in Reno, Nev.

“The changes we’re seeing in Jupiter are global in scale,” Orton said. “We’ve seen some of these before, but never with modern instrumentation to clue us in on what’s going on. Other changes haven’t been seen in decades, and some regions have never been in the state they’re appearing in now. At the same time, we’ve never seen so many things striking Jupiter. Right now, we’re trying to figure out why this is all happening.”

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2012-328

Planet Found In Nearest Star System To Earth

October 18, 2012 Leave a comment

European astronomers have discovered a planet with about the mass of the Earth orbiting a star in the Alpha Centauri system — the nearest to Earth. It is also the lightest exoplanet ever discovered around a star like the Sun. The planet was detected using the HARPS instrument on the 3.6-metre telescope at ESO’s La Silla Observatory in Chile. The results will appear online in the journal Nature on 17 October 2012.

Alpha Centauri is one of the brightest stars in the southern skies and is the nearest stellar system to our Solar System — only 4.3 light-years away. It is actually a triple star — a system consisting of two stars similar to the Sun orbiting close to each other, designated Alpha Centauri A and B, and a more distant and faint red component known as Proxima Centauri. Since the nineteenth century astronomers have speculated about planets orbiting these bodies, the closest possible abodes for life beyond the Solar System, but searches of increasing precision had revealed nothing. Until now.

“Our observations extended over more than four years using the HARPS instrument and have revealed a tiny, but real, signal from a planet orbiting Alpha Centauri B every 3.2 days,” says Xavier Dumusque (Geneva Observatory, Switzerland and Centro de Astrofisica da Universidade do Porto, Portugal), lead author of the paper. “It’s an extraordinary discovery and it has pushed our technique to the limit!”

Full Story: http://www.eso.org/public/news/eso1241/

Giant Impact Scenario May Explain The Unusual Moons Of Saturn

October 18, 2012 Leave a comment

Among the oddities of the outer solar system are the middle-sized moons of Saturn, a half-dozen icy bodies dwarfed by Saturn’s massive moon Titan. According to a new model for the origin of the Saturn system, these middle-sized moons were spawned during giant impacts in which several major satellites merged to form Titan.

“We think that the giant planets got their satellites kind of like the Sun got its planets, growing like miniature solar systems and ending with a stage of final collisions,” Asphaug (professor of Earth and planetary sciences at the University of California, Santa Cruz) said. “In our model for the Saturn system, we propose that Titan grew in a couple of giant impacts, each one combining the masses of the colliding bodies, while shedding a small family of middle-sized moons.”

Full Story: http://news.ucsc.edu/2012/10/saturn-moons.html