Thursday, February 24, 2011


Astronauts talking from the movie Deep Impact...
Mark: How do we set the nukes inside the comet and get out before they blow?
Orin Monash: We don't.
Andrea: Look on the bright side. We'll all have high schools named after us.
One of the open questions in science is, "Where are all the aliens?"  Given the immense number of stars and all the planets we are busily detecting, it just does not make sense that we are alone. There are four popular theories that I know of:

1. Stay hidden or else the militaristic aliens will get you
2. Intelligent machines eventually take over each planet
3. Periodic supernova sterilize regions of galaxies
4. Civilization is wiped out by a meteor impact

We know that Earth has been hit by meteors in the past - some of them were pretty big as in Arizona and the Yucatan. NASA takes seriously the chance that it will happen again by tracking the path of all known asteroids.

Presently all eyes are on asteroid, Apophis. In 2004, NASA scientists announced that Apophis, an asteroid larger than two football fields, could possibly smash into Earth in 2029. After taking more measurements, NASA decided that Apophis will pass by the Earth on April 13, 2029 at a distance of five earth widths. Very close! The moon is about 30 earth widths away.

This year Russian scientists have predicted that the 2029 fly-by will alter the orbit of Apophis in such a way that it will collide with Earth in 2036. NASA is not convinced. They put the odds of this happening at 1 in 250,000. About the same odds as a person being hit by lightening in a given year. (Though I have seen various odds for lightening 1/250K, 1/500K, 1/750K per year per person.)

Bottom Line

You can bet that when Apophis makes its next fly-by in late 2012 it will be extensively observed with ground-based telescopes and radars. If improved calculations put it on a destructive path, NASA will have 24 years to find a way to alter the asteroid’s orbit. Unlike the movies, blowing it up with nuclear bombs is not a good solution - this just changes the impact from one big rock to many smaller rocks. The best hope is to nudge it or push it into a safe orbit.

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