Posted: Jun 06, 2011 11:49 am
OK, there is still one key fact that we don't know: how close the object approaches the earth (enough "to take some of our atmosphere", however close that is!). But if this is an object with, as you say, ten times the Earth's mass and crosses the Earth's orbit that close at a right angle, travelling more or less directly away from the Sun, then it would surely (without my having done any actual maths) knock the Earth out of its orbit (into a different, less circular orbit), away from the Sun, and that alone would be pretty bad news for life as we know it, without postulating a head-on collision later (after the object, presumably, has swung round the Sun one more time).