Incredible Near Miss Asteroid to Zoom Past Planet
NASA Articles 1/26/12
By: Chris Capps
It's the scene in the disaster movie where the plot really starts rolling. At 4:30 in the morning a phone rings and a respected astronomer receives a call informing him that an asteroid is heading toward Earth. After a moment of talk, the astronomer looks dead into the distance and makes an expository appeal that this is "the big one." Only in the case of 2012 BX34, the phone call ended far less dramatically.
2012 BX34 is on one of the closest near-miss approaches toward Earth of an object detected in space ever recorded with a distance of approximately 60,000 kilometers. When it was first detected on Wednesday it became a point of interest for its closeness, but it was quickly apparent that the object would not reach close enough to actually strike Earth. For some perspective, let's take a look at some of the previous near miss asteroids in recent years.
In 1989 the asteroid 4581 Asclepius came within 700,000 kilometers from the Earth's surface as it passed by. The object was an estimated 300 meters across. Asclepius was recorded as having passed by the Earth's shadow, flying directly through the place the Earth had been only six hours prior. If the Earth had for some reason been six hours behind where it was in its journey around the sun, Asclepius would have struck the planet with more power than the most powerful nuclear bomb ever detonated - keeping in mind that the Tsar bomb detonated by the Soviet Union had a megaton payload estimated to be equivalent to roughly 57 million tons of TNT. It's unknown what the devastation of this asteroid hitting Earth would have done, but experts generally agree that we would still be feeling the effects of such an impact centuries after it happened - if we survived.
But not all near Earth asteroids have quite that level of devastating potential in them. In 2004 a near Earth asteroid was noted with an estimated diameter of 30 meters. The object was detected at its closest a mere 42,600 kilometers from the Earth. After the discovery, astronomers noted that it was likely something this small would come near Earth about that close once every two years with or without their being detected.
But given the magnitude of the near misses Earth has had in recent years, the presence of an object such as this, while interesting from a scientific perspective - does not necessarily yield the same level of doomsday weight as others. But if the idea of clear skies seems naive, you may be right. Though astronomers scrutinize the sky looking for asteroids every day, the 1979 Vela incident is often cited as one time when a massive asteroid slipped through the cracks and broke up in the Indian ocean detected by nuclear test radar searching for illegal nuclear tests. The impact was so large that - had it happened near a populated city - the devastation would have been incalculable.