Want to stay on top of all the space news? Follow @universetoday on TwitterThe chance of an asteroid collision is something that science needs to keep an eye on. Luckily, NASA and the Air Force already do. Every object in the solar system has been struck by at least one asteroid in its lifetime. The Earth has been struck dozens of times with the latest happening less than 100 years ago in Siberia. We should never question if an asteroid collision will ever happen again, but when will it happen and are we prepared for the collision.
Small objects impact the Earth with startling regularity. Asteroid collisions happen so often that science has a predicted pattern for impacts of larger objects. Scientists predict that asteroids larger than 1 km in diameter collide with the Earth every 500,000 years. Collisions with asteroids that are 5 km happen about every 10 million years. Asteroids with diameters of 5-10 m happen on a yearly basis, but they burn up in the atmosphere. All people really ever see of them are bright streaks in the sky.
An asteroid collision of an object that is over 50 m in diameter happens about once every 1000 years. It is thought that an incident of this type happened near the Tunguska River in Siberia in 1908. The area is remote, Soviet cooperation is low, and science has had little chance to study the area, but there was a great amount of forest devastation and some loss of life.
NASA thinks that the chance of a asteroid collision is real enough that is has set up the SENTRY and NEAT programs to study near Earth asteroids(NEAs). In the next 28 years there are supposed to be at least two close calls. Neither asteroid should actually collide with the Earth, but they will be close enough that Earth’s gravity could pull them off their orbit enough to cause a strike the next time they come our way. Hopefully, NASA will have a rover or something that they can send out to these asteroids to get samples and other information.
There is evidence of asteroid collision all over the Earth. It is thought that a large asteroid collided with the Earth and changed the environment enough to kill off the dinosaurs. There isn’t a body in the universe that does not have asteroid collision craters on its surface. Hopefully, we will be prepared for the next one that hits the Earth.
Here are links to the wiki page on asteroid collisions and NASA observations of NEAs. Here is where you can find information about the asteroid that wiped out the dinosaurs and here is an episode of Astronomy Cast the should interest you.