Tuesday, March 10, 2009

A Close Shave

This is a few days old but it is a reminder of just how busy space is. That the odds for a seriously damaging impact are low means nothing if you are at ground zero.

We are fortunate that geological events are proving to have a history of repetition and preliminary activity. It has become possible to establish warning systems and rapid reaction response systems. That we have not done enough yet is a given, but the cost is dropping and the expertise is rising. At some point, I expect that a satellite will pick up all the preliminary noise and trigger warnings based on excellent modeling.

We are a long way from doing the same for incoming asteroids and comets. Certainly what we know of their history and energy, we ultimately will. Just not with our current level of knowledge and expertise.

What just blew by would have been a very big atomic bomb in terms of energy release. It is still quite smallish. Anyway, the bad ones can be expected to scour a region at least fifty miles across through shock.

Seriously bigger than that, and we start hammering the entire globe. The blast that hit us almost thirteen thousand years ago in the northern ice cap released energy that appears to have been fully felt throughout the rest of North America and must have been also felt more survivably everywhere else.

The only way we can protect ourselves from these events will be to disturb their orbits at aphelion, likely way out in the Kuiper belt. We are a long ways away from that.

Space rock gives Earth a close shave

by Staff Writers

Paris (AFP) March 3, 2009

An asteroid of a similar size to a rock that exploded above Siberia in 1908 with the force of a thousand atomic bombs whizzed close past Earth on Monday, astronomers said on Tuesday.

2009 DD45, estimated to be between 21 and 47 meters (68 and 152 feet) across, raced by at 1344 GMT on Monday, the Planetary Society (http://planetary.org/news/2009/0302_Space_Rock_Swoops_by_Earth.html) and astronomers' blogs reported.

The gap was just 72,000 kilometers (44,750 miles), or a fifth of the distance between Earth and the Moon and only twice the height of satellites in geosynchronous orbit, the website space.com said.

The estimated size is similar to that of an asteroid or comet that exploded above Tunguska, Siberia, on June 30 2008, flattening 80 million trees in a swathe of more than 2,000 square kilometres (800 square miles).2009 DD45 was spotted last Saturday by astronomers at the Siding Spring Survey in Australia, and was verified by the International Astronomical Union's Minor Planet Centre (MPC), which catalogues Solar System rocks

No comments: