No Black Hole Or Magnetic Monopole: Tunguska Really Was a Meteor 128
davide-nature writes "The mysterious blast that flattened 2,000 square km of a remote Siberian forest in 1908 has been blamed on the most bizarre causes, such as an exotic elementary particle left over from the Big Bang, a black hole or, of course, aliens, including in the double-episode 'Tunguska' of The X-Files. But a new analysis of tiny rock samples suggests that a more mundane explanation — a meteor exploding in the atmosphere — may be the right one. The blast is estimated to have packed between 3 and 5 megatons, 10 times the energy of the meteor that exploded over Russia earlier this year."
Re:Hm, wasn't aware there was any controversy (Score:5, Informative)
Re:Hm, wasn't aware there was any controversy (Score:5, Informative)
How would they know the sticks were at a 90 degree angle? Aliens remain the simplest explanation without resorting to geometric constructions(which are hard)...
A right angle is one of the simplest geometric constructions there is. You can construct the perpendicular to a line at any point with three applications of a compass (which can be as simple as a marking device on the end of a string) and one use of a straightedge.
http://www.mathopenref.com/constperplinepoint.html [mathopenref.com]
There is also the 3-4-5 right triangle, which only requires the ability to produce edges which are integer multiples of a reference length.
Re:megatons != megatonnes of TNT (Score:4, Informative)
*facepalm* "Megaton" and "megatonne" are the same thing they are just variant spellings. They both mean 1 million ton(nes). The term is also used to refer to 1 million ton(ne)s of TNT as in the measure of TNT equivalence, but the distinction you claim does not exist.