Monday, 21 July 2014

The cosmos is dark and full of surprises

Recently on my fanpage (yep, the Polish one, people don’t think out loud on English one yet, but you are more than welcome to do so) someone expressed doubts whether Pluto will surprise us once New Horizons sends us data in 2015. It may be a blind guess, but I’ll confidently say – yes.

Pretty much every time we got a clear look at astronomical objects, they greeted us with surprises. Uranus turned out to be “the tilted planet”, its poles are where most planets keep their equators. If that’s not enough, its magnetic field seems to ignore the planet’s rotation and its geometric center. The axis of Uranus’ magnetic field is 60’ ajar from its rotational axis and its center is third of its radius away from the planet’s core.

Neptune is ten astronomical units further away than Uranus, it gets 60% less heat from the Sun, yet its internal heat drives the fastest winds in the solar system (over 2000 kph). Composition of both gas giants is similar, so astronomers are still scratching their heads how exactly the more distant planet has more internal heat.

In 2011 Dawn spacecraft reached Vesta, the second largest body in the asteroid belt. This too didn’t go without surprises. Flattened, probably by a giant impact, it turned out to have series of deep ridges around the equator. Its biggest crater is whooping 460 km in diameter. Impressive, given that diameter of Vesta is 570 km.

Moon Mimas surprised us by looking pretty much like the Death Star. That’s thanks to a crater so big that scientists don’t know how it’s possible that Mimas survived such impact. Iapetus, a satellite of Saturn, has a weird equatorial ridge making it look somewhat like a walnut. It also has a very distinct two-tone coloration, one side is dark brown, while other is bright white. Miranda, circling Uranus, looks like it has been shattered into pieces and put back together.

Second and final impulse to write this entry was the set of pictures taken by the Rosetta spacecraft. As it makes its way to comet 67P/Churyumov-Gerasimenko it sends us ever sharper images. And the newest one revealed a pretty damn surprising shape. 67P clearly seems to be composed of two pieces and that’s not very comet-like. I personally think 67P should be immediately renamed a “rubber ducky”. Given very turbulent lifestyle comets lead, with extreme temperature changes, tidal forces when moving near the Sun, ice and gas pockets blown by heat… it’s really interesting that it has such a shape.

Bottom line is – I have no doubt that comet Churyumov-Gerasimenko has still much in store for us, and that in 2015 world will be mesmerized and surprised by photos of Pluto, its moons caught by New Horizons, and by photos of Ceres snapped by Dawn.

Upper-left: Comet 67P/Churyumov-Gerasimenko (Rosetta)
Middle-right: asteroid Vesta (Dawn)
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