Saturday, June 12, 2010
Here's a really interesting study that is garnering some attention, that concludes that some 90% of the Oort Cloud must have originated from somewhere other than our own solar system. Keep in mind of course that the Oort Cloud itself is still theoretical, though since there is no better explanation for the weird orbit of the comets we know it's safe to assume that it's there. What's interesting about the idea of most of the comets originating from other parts of the galaxy is that it makes our own Solar System that much more interesting than we thought even just a decade or two ago. Instead of the traditional "nine planets then a bunch of nothing until you hit Alpha Centauri" we may end up with eight big planets, dozens and dozens of minor planets, comets and other stuff from other solar systems out to a light year or so, and hopefully even a brown dwarf or two or three in that space we originally thought to be pretty boring.
On that note, WISE has now covered a majority of the sky:
Of course, confirming discoveries of asteroids, comets and brown dwarfs will use the assistance of earth-bound observatories so covering 84.3% of the sky doesn't mean that the majority of WISE's discoveries have been announced; not even close. The mission also has about four and a half months left, so just a bit over half of the mission time has elapsed.