Asteroid Belt – Concept, origin and distance

We explain what the asteroid belt is and its distance from the Sun. In addition, the theories about how it originated.

Asteroid belt
The Asteroid Belt is made up of several million celestial bodies.

What is the asteroid belt?

It is known as Asteroid Belt or Main Belt to a region of our Solar System located between the orbits of Jupiter and Mars, that is, separating the inner planets from the outer ones. It is characterized by hosting a multitude of rocky astronomical objects, of irregular shape and different size, known as asteroids, and accompanied by the dwarf planet Ceres.

The name of the main Belt is given to differentiate it from other groups of space objects in the Solar System, such as the Kuiper Belt, located behind the orbit of Neptune; or like the Oort Cloud, at the very edge of the Solar System, almost a light-year from the Sun.

The Asteroid Belt is composed of several million celestial bodies, classifiable into three types: carbonaceous (type-C), silicate (type-S) and metallic (type-M). The largest objects present are five: Palas, Vesta, Higia, Juno and the largest of all: Ceres, classified as a dwarf planet, with a diameter of 950 km. These objects make up more than half the mass of the main belt, equivalent to just 4% of the mass of the Moon (0.06% of the Earth’s mass).

Although in the representations they are shown close, forming a compact cloud, the truth is that these asteroids are so far away from each other that it would be difficult to navigate that region of space and come across any. On the other hand, due to the usual orbital oscillations that they present, due to their eventual approaches to the orbit of Jupiter (and, therefore, to the effects of its gravity), many asteroids leave the set and are thrown into outer space, or even against some of the inner planets.

Distance of the asteroid belt from the Sun

The objects that make up the Asteroid Belt orbit between Jupiter and Mars, between 2.1 and 3.4 Astronomical Units (AU) of the Sun, that is, between 314,155,527 and 508,632,758 kilometers from the Astro Rey.

Origin of the asteroid belt

Asteroid belt
The Asteroid Belt may be part of the Proto-Solar Nebula.

The most accepted theory regarding the origin of the asteroid belt is part of the protosolar nebula from which the entire solar system came. I mean, it could well be the result of dispersed matter that failed to form a larger body, in part due to the intrusion of gravitational waves from Jupiter, the largest planet in the Solar System. This would have caused the rock fragments to crash into each other or would have ejected them into space, surviving as little as 1% of the initial total mass.

Older hypotheses suggest that the asteroid belt would have been some planet formed from the primitive nebula, but that it had been destroyed by some orbital impact or internal explosions. However, such a hypothesis seems unlikely given the low mass of the belt in contrast to the very high amounts of energy that would be required to blow up a planet in this way.