Asteroid Belt: Location, Shape, and composition

Introduction

An Asteroid belt is a small part of rocks floating in space. Most of the asteroids in our solar system are located between the orbits of Mars and Jupiter. Astronomers believe that asteroids are the remains of planets and moons that have been in existence since the formation of the celestial body more than 4.5 billion years ago. They could also be destroyed by a collision between planets, moons, and other asteroids. In some places in the galaxy, asteroids accumulate in large clusters orbiting the sun (1).

Where is the asteroid belt located?

  • They are located between the orbits of the giant planet Jupiter and the red planet Mars in our solar system.
  • The asteroid could marge on a planet if it weren’t for the gravitational tug-of-war between Mars and Jupiter.
  • Astronomers have noted and named more than 828,600 asteroids in this belt. There are probably millions of asteroids in the asteroid belt. It is about 3.2 AU (Astronomical Units) far from the sun.
  • The average distance between objects in the asteroid belt is quite large. The distance between the Earth and the asteroid belt is 3.2-4.2 AU (297.45 -390.4 million miles) (3) & (4).

What is the Asteroid Belt?

Asteroids are rocky pieces left over from the creation of the solar system about 4.5 billion years ago. Most of these pieces of ancient space debris sometimes referred to by scientists as minor planets can be found orbiting the sun in a belt between Mars and Jupiter. This region in our solar system is called the Asteroid Belt or Main Asteroid Belt. The main asteroid belt is a living relic. Since the formation of the planet, the Asteroid Belt has been a record of what happened to the solar system in terms of bombardment (5).

Asteroid belt facts

1. There are between 1.1 and 1.9 million asteroids in the asteroid belt in our solar system.

2. It is made of rock, stone, and metal and is disc-shaped.

4. Most of the asteroid orbits the sun in a belt about 1.5 au wide between the orbits of Mars and Jupiter.

5. The asteroid belt is crowded with asteroids that share an orbital path.

6. About 90% of asteroids lie in the asteroid belt between Mars and Jupiter.

7. The size of the asteroid belt object is as small as dust, about 1000 km wide.

8. The four largest objects in the asteroid belt are Ceres, Vesta, Pallas, and Hygiea.

9. Astronomers believed that the objects contained in the Asteroid Belt were the remnants of a planet smaller than the moon that exploded.

10. Ceres, the dwarf planet, was the first object to be noticed. (2) & (4).

What Asteroid Belt is made of?

These are mostly made up of rocks, stones, and metals like iron and nickel.  Some are made of carbon-rich materials. Asteroids that are far away from the sun also have ice therefore, there is evidence that some asteroids have water (3).

Asteroid Belt observation history

In 1596 Johannes Kepler predicted that there was a planet between Mars and Jupiter in his Mysterium Cosmographicum. In 1766 the astronomer Johann Daniel Titius noted that there was a missing planet between the orbits of Mars and Jupiter. When William Herschel discovered Uranus in 1781, the orbit of the planet was almost perfectly aligned with the law, so astronomers concluded that a planet had to be in the orbit of Mars and Jupiter.

In 1800, the Celestial Police was formed to search the heavens for the so-called” missing planet”. The group has 25 astronomers, each exploring the Zodiac at 15°. However, on 1st January 1801, the Italian astronomer Giuseppe Piazzi first discovered the body and named it Ceres. The second body was found a year later and was named Pallas, discovered by Hinrich Olbers. For a long time, scientists have assumed that these are two planets, but in the 19th century, more than 100 heavenly bodies were found in the region. They were too small to be considered planets. And so they called them asteroids, or “star-like”. Piazzi was the first to discover the Asteroid Belt (2) & (3).

Formation of Asteroid Belt

It is formed of a primitive solar nebula as a group of galaxies.

1. When our solar system was in its early life, the rock and dust orbited the sun and were drawn together by gravity eventually forming our planets and moons. However, all the ruins used to create this new earth did not end in the region between Jupiter and Mars.

2. Some scientists once thought that the asteroid belt could be the remains of a destroyed planet.

NASA then configured the entire belt mass to be lower than our moon. Hence the theory of destroyed plants was rejected. This means there is not enough debris to make it a planet. The left parts are held by Jupiter’s gravitational pull, and since the pieces are so far apart they have never been too close to each other to try to become another planet or moon (2).

Composition of Asteroid Belt

It is classified into several types. Each is based on their reflection and composition. They are formed primarily of three categories of asteroids. These are C-type of carbonaceous asteroids, S-type or silicate asteroids, and M-type or metallic asteroids.

1. C-type asteroid

About  75% of asteroids are located in C-type of the asteroid. C-types of asteroids are made of carbon. They are among the most ancient objects in the solar system. The surface of these is extremely dark.

2. S-type asteroid

Around 17% of asteroids are situated in S-type asteroids. These asteroids are made of silicate. These are mostly located in the inner belt. The synthesis of nickel-iron, which is mixed with iron and magnesium silicates, makes the S-type of asteroid even brighter.

3. M-type asteroid

M-type asteroids are made of nickel and iron. These are in the center region. In the asteroid belt, these asteroids are very bright (3) & (6).

The Collision of Asteroid Belt

Many asteroids together create a very active environment, where collisions between them occur most frequently. With an average radius of 10 km in length, collisions between major belt companies are likely to occur approximately once every 10 million years.

Fast collision results in a further breakdown of asteroid belts thus the formation of a new asteroid family. On the contrary slow collision at low relative speeds can join two asteroids.

In addition to the asteroid body, it also contains dust with particles up to several hundred meters. This fine element is produced, at least in part, from the collisions between the asteroids and by the effect of the micrometeorite on the asteroids. Due to the Poynting- Robertson effect, the dust gradually inflates inside the sun to the pressure of solar radiation.

The collision of asteroid belts also forms a Metroid in the Earth’s atmosphere. Of the 50,000 meteorites found on Earth to date, 99.8% are believed to have arisen in the Asteroid Belt. There is strong evidence that the mass extinction that killed the dinosaurs about 65 million years ago was caused by an asteroid at least 12 km wide (2).

The shape of the Asteroid Belt

The Asteroid Belt is a torus-shaped region in the solar system. Some asteroids are more than a mass of rubble stacked together by gravity.

The planets and moons are round and the shape is due to the strong gravitational force. Asteroids in the belt don’t have strong gravity so their shapes and structures are irregular.

Many have the appearance of bald potatoes. 216 Cleopatra is almost like a dog’s bone to see asteroids. They are classified into several types. Each is based on their reflection and composition (2) & (5).

Atmospheric Condition

The temperature of the asteroid belt varies with distance from the sun. For dust within the belt, the general temperature is from 200 K (-73°C) to 2.2 AU to 165 K (-108°C) at 3.2 AU, however, due to rotation, the temperature of an asteroid’s surface can vary considerably as the sides gradually withstand solar radiation (2).

Mass of Asteroid Belt

Four big asteroids namely Ceres, Vesta, Pallas, and Hygiea comprise half the mass of the total asteroid belts. The total mass is about 4% from the moon or 22% from Pluto and twice the diameter of Pluto’s moon (whose diameter is 1200 km). The belt is estimated to have 1.1 to 1.9 million asteroids larger than 1 km (0.6 miles) in diameter and several million smaller ones.

The size of the asteroids is both small and large. These asteroids have played a role in the evolution of life on Earth. Some of the asteroids are quite large. Ceres is a dwarf planet, about 950 km in diameter on the asteroid belt. Vesta, Pallas, and Hygiea have mean diameters of less than 600 km. The total mass of all the asteroids combined is less than the Earth’s moon (3) & (6).

Could Life Exist in the Asteroid Belt?

Asteroids have no stability in orbit. Some asteroids have ice water. But there is no atmosphere. So there is no life that exists there (2).

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