Rosetta's Comet Is Actually 2 Comets Stuck Together

astroengine writes: Scientists have solved the mystery of why the comet being studied by Europe's Rosetta spacecraft is shaped like a rubber duck — it started off as TWO separate comets, a new study shows. Ever since Rosetta sent back pictures of its twin-lobed target more than a year ago, scientists have debated whether the comet, known as 67P/Churyumov-Garasimenko, could be the result of two comets that merged together during the solar system's early years. The other option is that the so-called "neck region" between 67P's two lobes experienced some particularly active and still unexplained outgassing over the eons, eroding its more spherical shape into a body that resembles a rubber duck. "Our study rules out the possibility that the comet shape is the outcome of erosion," planetary scientist Matteo Massironi, with the University of Padova in Italy, wrote in an email to Discovery News. Rather, the neck region is where two independent bodies collided, analysis of high-resolution images taken by the orbiting Rosetta spacecraft shows.

Comments

Not surprising and kind of arbitrary

[DumbSwede]

Almost everything in the solar system built up by accretion. Small bodies aggregate into larger ones by collision. If the bodies have enough mass they coalesce into spherical forms under gravitational attraction.

This comet probably started out has hundreds of bodies (millions, billions, trillions, depending on where you decide the cut off is between body, dust, molecule) -- of which we are focusing on just one of the last, largest collisions.

think.. think they know

[Virtucon]

They think they know. They've done some homework, some research and have come up with a couple of hypothesis. They think they've ruled out one but they don't actually know. FTFY

I for one hold out hope for the large drinking rocks theory where the shape was determined by an over-wash of Jack Daniels.