How do we track deep space objects like comets and asteroids?

Everything Earth can encounter (and collide with) in the solar system is falling towards and/or around the Sun. This is a simple result of how gravity works. When an object (stone, comet, planet, etc...) is falling around the Sun, we call it 'orbiting'. read more

Space objects near the Earth (but not in orbit about Earth) are orbiting the Sun. At Earth's distance from the Sun, they will moving about 30 km/s If they hit Earth at an angle, the speed will be more or less. read more

Telescopes and math. Observations of asteroids and other near-Earth objects are made optically; in the case of this week's flyby, researchers at Spain's La Sagra Observatory discovered the asteroid (called 2012 DA14), in February of last year. read more