It is a collection of millions of space boulders that revolve around the Sun, between the orbits of Mars and Jupiter. The curious thing is that all planets formed from such belts. 4.6 billion years ago, everything that exists here on Earth was in pebbles that roamed a belt of the solar system, much like the belt today. The difference is that these stones came together, attracted by each other’s gravity. And they came together to form a beautiful pedrona that today we call Earth. But if this happened to all the planets, why is there an asteroid belt left? Because of a tug-of-war between the enormous gravity of Jupiter, the largest planet in the system, and that of the Sun. The key is the following: the more mass a star has, the greater its gravity, its power of attraction over things. who are close to him. “Since the asteroids are halfway between Jupiter and the Sun, the planet pulls them one way and the star the other.
The gravity of the rocks is not enough to overcome these forces, and they cannot coalesce”, says astronomer Roberto Dias da Costa, from the University of São Paulo (USP). At the origin of the solar system, the water vapor that was where Jupiter is today found a temperature low enough to turn to ice. As the amount of ice was, and still is, far greater than that of other solid elements in space, what would become the largest planet in the solar system soon gained a core. This, in turn, provided gravity for the star to grow too fast, until it had a mass 318 times greater than that of Earth. With such a giant around, it was impossible for the asteroid belt to become a planet. Jupiter even swallowed most of the boulders that orbited this region. So much so that if the remaining space rocks in the belt came together, they would form a planet half the size of the Moon.
space tug of war
Rocks did not form a star because of the gravitational dispute between the Sun and Jupiter
1. Everything that forms the solar system today came from a cloud of dust. Gravity caused it to condense into a disk shape 4.6 billion years ago. In the middle was the ball of matter that would become the Sun. About 98% of the mass of this disk was formed by hydrogen and helium, the lightest and most common atoms in the Universe.
two. At the center of the disk, matter became so tightly packed that atoms began to fuse together. This nuclear fusion “turned on” the Sun, creating an energy source that pushed most of the light hydrogen and helium atoms away. These then coalesced to form Jupiter, Saturn, Uranus and Neptune. As these elements were abundant, such planets became huge
3. A good part of the heavy atoms, such as iron and oxygen, stayed close to the Sun, attracted by the star’s gravity. They coalesced, forming pebbles. The gravity of the larger stones attracted the smaller ones. Then the rocks grew into asteroids. And they too came together, becoming Mercury, Venus, Earth and Mars – the rocky planets, smaller and denser than Jupiter & Co.
4. Each of the “bands” of the disk that originated the solar system ended up occupied by a planet, except one: between Mars and Jupiter. It was full of asteroids that could not come together to form a large star. It’s just that they are pulled by both the enormous gravity of Jupiter and the Sun. In the midst of this dispute between the titans, the gravity of the asteroids was not enough to unite them
pebbles and pebbles
Most of the asteroids that form the belt are the size of boulders, a few meters in diameter. But some are respectable: 16 are over 240 kilometers in diameter. The biggest is Ceres, with 700 kilometers. If brought to Earth, it would cover the distance between São Paulo and Florianópolis. Fun fact: some astrologers consider it as a planet in their birth charts