Doomsday

We ignore this real threat to the Earth at our peril, and for a change I'm not talking about Islam. Instead, it's big hunks of rock.

It's important to realize we really aren't yet on top of this problem, we don't have the whole sky covered, we could be whacked by a civilization-ending comet tomorrow without any warning, and even if we saw it coming there's likely NOTHING we could do about it.

Oh, in principle things could be done, but we haven't spent the money to get ready.

The risk is very real:

Six months later, Tholen's object was spotted again in Australia as asteroid "2004 MN4." In the space of five days straddling Christmas, startled astronomers refined their calculations as the probability of the 1,000-foot-wide stone missile hitting Earth rose from one chance in 170 to one in 38.

They had never measured anything as potentially dangerous to Earth. Impact would come on Friday the 13th in April 2029.

The holidays and the tsunami in South Asia pushed 2004 MN4 out of the news, and in the meantime additional observations showed that the asteroid would miss, but only by 15,000 to 25,000 miles -- about one-tenth the distance to the moon. Asteroid 2004 MN4 was no false alarm. Instead, it has provided the world with the best evidence yet that a catastrophic encounter with a rogue visitor from space is not only possible but probably inevitable.

It also demonstrated the tenacity of the small band of professionals and amateurs who track potential impact asteroids, and highlighted the shortcomings of an international system that pays scant attention to their work.

"I used to say the total number of people interested in this was no more than one shift at a McDonald's restaurant," said David Morrison, an astronomer at NASA's Ames Research Center and a student of near-Earth objects for nearly three decades. "Now it's maybe two shifts." Awareness of the apocalyptic potential of near-Earth objects has been slow to develop.

Missile-defense technology obviously has applications in this area. Those opposed to our being able to defend ourselves are putting all of humanity at risk, needlessly.