Many people think of asteroids as being small chunks of rock that drift aimlessly and randomly through space. The reality, of course, is a little different, but it wasn’t until relatively recently that we began to discover more about them. For example, we now have a better idea of their origins and their composition.
Asteroids are the leftovers from the formation of the solar system. The planets came together about 4.6 billion years ago, with the rocky planets forming closest to the Sun. The asteroid belt, between Mars and Jupiter, is the remains of a planet that failed to form, most likely due to the gravitational interference of Jupiter. Most asteroids can be found there, although some can also be found in other locales within the solar system.
The largest asteroid, 1 Ceres, as imaged by NASA’s Dawn spacecraft. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The first asteroid was discovered on January 1st, 1801. Officially known as 1 Ceres, it has a diameter of 974km and is the largest known asteroid. (The smallest known asteroid is only six feet across, but others could be smaller.)
As of August 2020, there are a little over 990,000 known asteroids. In theory, anyone can discover an asteroid, ...