2 comments on “This Week in Science: August 16, 2015

  • @ “Young Jupiter” – There are hundreds of planets a little bigger than Earth out there, the researchers say, but there is so far no way to know if they are really “super-Earths” or just micro-sized gas and ice planets like Neptune or something altogether different. Using GPI to study more young solar systems such as 51 Eridani will help astronomers understand the formation of our neighbor planets, and how common that planet-forming mechanism is throughout the universe.

    The key issue is whether the star system has formed from a high or low metalicity nebula. (ie ones where there have been supernovae). Heavy denser elements are needed for rocky planets to form, and may be necessary for any smaller planets to form.

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  • Another noteworthy event is happening out by Saturn.

    The Cassini mission to Saturn has returned its final close-up images of the gas giant’s Dione moon.

    The probe passed within 500km of the pockmarked surface on Monday – its fifth such encounter in the spacecraft’s 11-year tour of the ringed planet.

    Cassini is now engaged in a series of observational “lasts”.

    And in 2017 it will put itself on a destructive dive into Saturn’s atmosphere.

    Dione has a diameter of 1,122km. It has an icy exterior and a rocky interior.

    Cassini has detected a wispy oxygen atmosphere at the world, and has also seen signs that it may still be active, with what appear to be regions on its surface that have been altered by internal processes.

    Next year, Cassini will begin a series of manoeuvres to put itself in orbits that take it high above, and through, Saturn’s rings.

    Then, in 2017, once the probe’s fuel has all but run out, ground controllers will command the spacecraft to plunge into the planet’s atmosphere, where it will be destroyed.

    As Cassini hurtles towards Saturn, it will become incredibly hot, will melt and ultimately will be crushed by huge pressures.

    The mission is being disposed of in this way to be sure there is no possibility that debris from Cassini can one day land on Enceladus and Titan. These moons have been talked of as candidates for extraterrestrial life, and scientists would not want them contaminated by any Earth microbes that might still be on the probe – however unlikely that might be.

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