Video of a Cosmic Close Call…

March 15, 2009

Two weeks ago, a small asteroid passed within just 72,000 km of Earth.  Moving at thousands of kilometers an hour, this rocky piece of space debris, some 20-50 m across,  was large enough to cause significant damage had it hit our planet.  Here’s a video of the asteroid as it passed by…


Basics

• The asteroid, called NEO 2009 DD45, was discovered by an astronomer at the Siding Spring observatory in Australia, just three days before its closest approach.  The asteroid is a dark, faint object, which is why it wasn’t discovered until it was very close.

• Had it hit the Earth, the asteroid was large enough to cause an impact the size the the 1908 explosion over Tunguska, Siberia, which flattened trees over a 2,000 square kilometers and rattled windows in Paris thousands of kilometers away.  A direct impact on a city or coastline by such an object would have been an historically destructive event.

• Here’s a video of the asteroid taken by an Australian amateur astronomer Dave Herald.  The asteroid moves across the middle of the screen, from right to left.

Deeper Look

• Every few tens of millions of years, on average, an asteroid 10 km or so in size hits Earth.  The last one caused the extinction of the dinosaurs and many other species.

• If another large asteroid is found to be on an imminent collision course with Earth, you had best get your affairs in order.  While there’s a small chance of changing the orbit of the asteroid by attaching a rocket to its surface and pushing it away, a great deal of advanced warning and technical innovation is required, so there is a limited hope of success.

A Bit of History

The closest known approach of an asteroid to Earth occurred in March 2004, when 2004 FU162 passed within 6,500 kilometers.  It was 6 meters across, large enough to cause significant, but not catastrophic damage to a city.

Personal View

Despite this alarming news, don’t get too concerned about stray asteroids.  There are far more immediate dangers.  The chance of a major asteroid impact in your lifetime is roughly one in a million.  The chances of dying in a car accident in your lifetime?  Less than one in 100.  So forget about space rocks for now, and make sure you buckle up!

Posted in Celestial Objects