# How large would an impact have to be to destroy earth? [duplicate]

Supposing I had a planet the size of the earth, how much mass and how much velocity would an impacting body have to have to completely annihilate the planet? That it is to say that its reduced from a coherent planet to a shattered cloud of debris spread out over its former orbit, maybe a bit like an asteroid belt.

How would the impacting body compare to other objects in the solar system?

• I'm 30% certain what-if XKCD on the topic exists :) Jul 16 '15 at 19:55
• I tried to look that up but I can't find anything on it, could you link it if possible? Jul 16 '15 at 20:06
• @DVK I don't remember and can't find exactly that, but Diamond gives some data points. Jul 16 '15 at 20:09
• Have we seriously not covered this?! I feel like we have... Jul 16 '15 at 20:17
• @James Related: worldbuilding.stackexchange.com/questions/4679/…, specifically, worldbuilding.stackexchange.com/questions/4679/… Jul 16 '15 at 20:24

the answer is 2.24 $\times$ 10$^{32}$J.