Asteroid Earth

For years sci-fi movies have been turning up the heat about an asteroid Earth collision. An attraction to that type of movie has sparked an interest for some in near Earth asteroids. Truthfully, there are thousands of them, but the most famous would have to be Apophis(also known as 2004 MN4). This asteroid generated a slight scare in 2004, but scientists worked their way through the fear and discovered quite a few interesting facts about this asteroid.

With a size of 270 m in diameter and 320 m wide, with a mass of 2.1 x 10¹⁰ kg, Apophis could have lived up to its Egyptian name for Uncreator. It is thought that a strike by an object that size could destroy 10 to 25% of the life on Earth. The team of Tholen and Tucker discovered the asteroid on June 19, 2004. Their hopes of a brand new discovery were somewhat squashed when older images of the asteroid were discovered in forgotten files. Luckily, those old photos existed. Using those old images as well as the new, astronomers were able to be sure that the asteroid was not going to impact the Earth.

The Earth is impacted by small asteroids and meteorites on a monthly basis. All of them are small enough to burn up in the atmosphere, leaving a nice light show as the only evidence of their passing. Apophis would be a little different. This asteroid is 320 m wide. That is enough to destroy an area the size of the Quebec province if it hit land or to cause horrific tsunamis if it impacted in an ocean. A little chilling for an asteroid that was predicted to have a one in sixty chance of hitting the Earth when it passed in 2004.

Dire predictions are typical of newly found asteroids, however. All newly found asteroids are given a score of 1 on the Torino scale when they are discovered. A 1 means that an asteroid simply needs further study, but some reporters panic and report about disaster being on its way. Astronomers actually go through a four step process when a new asteroid is discovered. They use this process to eliminate the possibility of an asteroid/Earth impact. The process is actually quite fast, so that there is no undue panic.

Here on Universe Today we have two great articles on the topic: one is about Earth impacts and the other is about the 10 most impressive craters on Earth. Astronomy Cast offers a good episode about craters around the solar system.

Reference:
Wikipedia

Tagged as: asteroid Earth