In this video you will learn about near-Earth asteroids. These are objects that can threaten our planet, that is, they cross the Earth orbit or come close enough to it. To date, 38.5 thousand such asteroids are known. Depending on the orbits parameters of near-Earth asteroids, they are divided into four groups: Atiras, Atens, Apollos and Amors.
Atiras are the group of asteroids whose orbits are completely limited by the Earth orbit (semi-major axis a is less than 1.0 AU, aphelion Q is less than 0.983 AU). This is the smallest group of near-Earth asteroids: to date, only 36 such objects are known. They currently pose no threat to the Earth, but the situation may change in the future as a result of their possible approach to Venus or Mercury.
Atens are asteroids whose orbits are almost completely inside the Earth orbit, while intersecting it (semi-major axis a is less than 1.0 AU, aphelion Q is more than 0.983 AU). Their danger lies in the fact that they usually approach our planet from the Sun, so they are difficult discover it. Now about 3 thousand Atens are known, including the famous Apophis.
Apollos are asteroids whose orbits are almost completely outside the Earth orbit, while intersecting it (semi-major axis a is greater than 1.0 AU, perihelion q is less than 1.017 AU). This is the largest group of near-Earth asteroids, with almost 22,000 discovered at the moment. Curiously, one of them (1999 XS35) appears beyond the orbit of Neptune at aphelion.
Amors are asteroids with orbits located entirely outside the Earth orbit, but almost touching it (semi-major axis a is greater than 1.0 AU, perihelion q is greater than 1.017 AU, but less than 1.3 AU). About 13.5 thousand Amors have been discovered, and some of them are moving away from hundreds of astronomical units of the Sun. Due to the approaches to the gas giants, their orbits can change significantly, they can become Apollos and pose an immediate threat to the Earth.
The orbits of many of the near-Earth asteroids are quite strongly inclined to the ecliptic plane. Therefore, not every one of them is considered potentially hazardous, but only a few thousand, which are quite large and, at the same time, have approaches to the Earth. The orbits of asteroids are subject to changes under the influence of planets with which they may approach. Previously unknown near-Earth asteroids are regularly discovered, for example, over the past six months their number has increased by one thousand. Their number may also grow due to collisions of large asteroids of the main belt and the disturbance of its objects from Jupiter. It is important to continue searching and cataloging near-Earth asteroids, as this contributes to solving the problem of asteroid hazards.
Modeling and rendering were performed by the author of this publication using own software. The calculations took into account the mutual influence of the Sun, all the planets of the Solar system and the Moon on each other. Relativistic effects were also taken into account in the calculation. The motion of asteroids is shown without taking into account planetary disturbances. Throughout the video, the sizes of celestial bodies are shown to be greatly exaggerated compared to the distances between them.
The music track Asher Fulero – Night Snow was used under a Creative Commons Attribution license.
