Asteroid + Earth Impacts: rising probability

Two articles (please read all of it) :

One, a one page "side bar" in Wired magazine for August, 2005, page 42

All it shows is a graphic of a bunch (about a dozen and a half) of discovered asteroids that are being tracked and thumbnail data presented in the graphic. Its got year found (all in the last ten years), name, size range, and odds of collision.

Bottom line #1: A few are kilometer sized. This means big craters that will ruin your day if it impacts near you (ground zero: a few city blocks). Bigger ones will have widespread negative impacts on life on the planet.

Bottom line #2: Most probabilities are very small, but asteroid SG344 (about 200 feet in diameter) has a probability of impact of one in 556 in the year 2068. Everything else is farther in the future and quite a bit lower probability.

Not to worry? Here are the caveats: The caption says NASA is funding a program to identify 90% of the potentially hazardous objects. Results: 15 times as many asteroids were discovered in 2004 as in 1995 (it says about 16 per day). Question: What is the total estimated number of asteroids and how many have orbital elements and diameter data that are known? One needs to worry about the undiscovered asteroids that are: i) big, and ii) cross our orbit with a higher probability of impact, and iii) when. 15 times as many being discovered today? Will we find, in the next couple of years, many more of the high probability collision rocks?

Article #2: The State News (Delaware, April 10, 2005, page 6) - enbreastled: "Loosely knit Doomsday team keeps an eye on asteroids" by Guy Gugliotta (Washington Post). The following is a quote from the article:

"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 missle 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."

Farther on down the article, a guy from JPL (Donald K. Yeomans, who manages NASA's Near Earth Object Program at JPL) said the bad news is that they can only detect these things nine months from impact.

Hey....you guys better pay attention to this stuff!