Guest Author - Barbara Melville

Asteroid 2009 DD45 made the news when it flew close to Earth on March 2nd 2009. According to the SpaceWeather site, the asteroid was 72, 000 km from Earth, making it inside the orbit of the Moon. This is close enough for astronomers to take notice, but not close enough for collision. Amateur astronomers in the Pacific region may have been able to view the object in the constellation Virgo.

Robert McNaught of the Siding Spring Observatory in Australia discovered the object two days before it flew by. In the article Asteroid nearly rocked our world in The Canberra Times, writer Nyssa Skilton reported that McNaught said although the asteroid would return, it poses no threat to Earth this century.

SpaceWeather describe the object as being around 35 meters in diameter, comparing it to a rock that entered the Earth’s atmosphere in 1908 – the Tunguska Event. On June 30th 1908, the rock probably exploded in the sky, resulting in the flattening of 80 million trees and the deaths of many animals. There were probably human deaths as well, though the region was fairly remote.

In his article The Tunguska Event--100 Years Later on the NASA website, Dr Tony Philips writes, “At 7:17 a.m. (local Siberia time), at a height of about 28,000 feet, the combination of pressure and heat caused the asteroid to fragment and annihilate itself, producing a fireball and releasing energy equivalent to about 185 Hiroshima bombs”. However, had DD45 hit, the effects may have been different.

Near Earth Objects (NEOs) are of considerable interest to space agencies, and there are several NEO institutions. In fact, Robert McNaught, the discoverer of 2009 DD45, was participating in an NEO program called the Siding Spring Survey. A well-known program is NASA’s NEO Program, which monitors objects that can enter Earth’s neighborhood.

For more information, an ephemeris (a table of positions) for 2009 DD45 can be found on NASA’s website. For those who would like to know more about the Tunguska asteroid, NASA also have a site covering the facts. If you were looking for information on 99942 Apophis, read the Will the Apophis Asteroid Hit Earth? article here at BellaOnline.

Sources

Asteroid 2009 DD45 Just Buzzed by Earth, Universe Today website, published: March 2nd 2009, accessed: March 8th 2009, author: Atkinson, N.

What’s up in Space (March 2nd 2009), SpaceWeather website, published: March 2nd 2009, accessed: March 8th 2009, author: Philips, T.

The Tunguska Event--100 Years Later, NASA website, published: June 30th 2008, accessed: March 8th 2009, author: Philips, T.

Asteroid nearly rocked our world, The Canberra Times website, published: March 5th 2009, accessed: March 8th 2009, author: Skilton, N.

Siding Spring Survey, The Australian National University website, accessed: March 8th 2009, no author specified.

Near Earth Object Program, NASA website, accessed: March 9th 2009, no author specified.