As spherical object with that size and made of water would weight ~1800 tons. If that's an iron asteroid, that would give over 10 thousand tons.
In terms of explosive power, it should be equivalent between 0.2 and 1 Megaton 2013/2/15 Jed Rothwell <[email protected]> > > > They say the object was 15 m in size, ~10 tons. > > - Jed > > -- Daniel Rocha - RJ [email protected]

