Post by Chicago Astronomer - Astro Joe on May 5, 2006 0:16:34 GMT -6
The Art of Asteroid Avoidance
Col. Gen. Vladimir Popovkin, commander of the Russian Military Space Forces, told a news conference Friday that the national satellite network lacked a spacecraft capable of preventing an asteroid strike.
He also said chances of such a collision were infinitely small, and it was inexpedient to spend huge sums on neutralizing this unlikely threat. Still, the general might be underestimating the scale of the asteroid threat.
Over the last few decades there has been a great deal of debate about the level of danger posed by impacts from asteroids and comets. It appears the world needs to take the threat of asteroid strikes a lot more seriously.
Astronomers have already spotted about 800 asteroids, solid rocky celestial bodies, with a diameter of over 1,000 meters (3,250 feet) moving along circumsolar elliptical orbits. However, there may be as many as 2,000 large asteroids, and some 135,000 rocks with a diameter of 100 meters (325 feet) and more.
It should be noted that asteroid orbits are unstable and tend to change under the influence of gravitational fields of the terrestrial planets - Mercury, Venus, Earth and Mars.
An asteroid, which flashed past our planet at a distance of 5 million kilometers (3.1 million miles) in November 1996, returned in September 2004 and flew by just 1.5 million kilometers (930,000 miles) from Earth's surface. In March 1989, a 300 meter (975 foot) asteroid crossed the terrestrial orbit and missed the Earth by just six hours. Astronomers spotted the rock only when it was receding into space.
Russia established the Space Shield Foundation east of the Urals. The organization involved scientists from the Snezhinsk (Chelyabinsk-70) nuclear center and the Makeev State Rocket Center in Miass. The foundation eventually set up subsidiaries in Novosibirsk and Korolev, outside Moscow.
The Planetary Defense Center, which was established in Russia three years ago, comprises the best defense-industry facilities, aerospace enterprises, in the first place, as well as academic and sectoral research.
Scientists say the best way to cope with the asteroid problem is to register and observe all potentially dangerous space objects. However, it is not enough to spot an asteroid, because most of them have unstable orbits; consequently such asteroids may disappear later on.
Every terrestrial hemisphere must therefore have three or four telescopes with primary mirrors 4 meters to 5 meters in diameter for observing asteroids round the clock. Such observations would make it possible to catalog asteroids with a diameter of less than 1,000 meters.
Full story here: www.astrobio.net/news/article1938.html
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I have my hardhat at arms reach at all times...
