Joe Knows: Happy Asteroid Day!
Is it a bird? Or a plane? Oh wait ... it's an asteroid! Today is Asteroid Day and researchers around the world are gathering to discuss near-Earth objects like asteroids and efforts to avoid or lessen the danger of future impacts.
There are currently 600,000 known asteroids in our solar system. Most happen to be found in a huge collection of them between the orbits of Mars and Jupiter known as the Kuiper asteroid belt.
Sometimes asteroids break off their orbit and can make close passes to Earth. We know from past experience that an impact from a large asteroid is not good, and can cause a mass extinction of life. There have been five mass extinctions in the 4.5 billion year history of Earth.
No known objects of cataclysmic size are now on collision courses with Earth, but smaller near Earth objects are still out there and are undiscovered by the millions.
NASA and other space agencies are now developing ways to deflect and redirect asteroids should they approach, but those techniques will be useful only if we find any dangerous near earth Asteroids before they find us.
By studying asteroids we get a sense of early Solar System, the violent collisions of rocks which helped to form planets and moons. They are key to figuring out how our Solar System came to be billions of years ago.