In our solar system, the Earth is surrounded by some nasty neighbours and they threaten to destroy everything in their paths. Including comets and asteroids, these are known as near-Earth objects (NEOs). These are small Solar System bodies whose orbit brings them into proximity with Earth.
The National Aeronautics and Space Administration (NASA), an independent agency of the US federal government responsible for the civil space program, has issued a list of potentially hazardous asteroids that can destroy our blue planet. Here is the list:
1) Amor asteroids
Named after the archetype object 1221 Amor, these are a group of near-Earth asteroids. With most Amors crossing the orbit of Mars, the orbital perihelion of these objects is close to but greater than, the orbital aphelion of Earth. There are 7427 known Amor asteroids in our solar system. 1153 are numbered. Scientists have named 75 of them.
2) Apollo asteroids
Named after 1862 Apollo, the Apollo asteroids are also a group of near-Earth asteroids. In the 1930s, they were discovered by German astronomer Karl Reinmuth. They are Earth-crossing asteroids. They have an orbital semi-major axis greater than that of the Earth. However, their perihelion distances are less than the Earth’s aphelion distance. With a diameter of about 8.5 km, the largest known Apollo asteroid is 1866 Sisyphus.
3) Aten asteroids
These are a dynamic group of asteroids. Their orbits bring them into proximity with our blue planet. Also known as, Earth-crossing asteroids, the group is named after 2062 Aten. It was the first of its kind. It was discovered on 7 January 1976. American astronomer Eleanor Helin discovered it at Palomar Observatory. Till now, 1841 Atens have been discovered. Thirteen are named.
4) Atira asteroids
These are those asteroids whose orbits are entirely confined within Earth’s orbit. In other words, their orbit has an aphelion (farthest point from the Sun) smaller than Earth’s perihelion (nearest point to the Sun). Compared to the Aten, Apollo, and Amor asteroids, Atira asteroids are till now the smallest group of near-Earth objects.