Introduction
Astrophysics is the major subject to develop knowledge about celestial objects. The study of the sun, the comets, the stars, asteroids, meteoroids, and galaxies is called astrophysics. The birth of the stars and their life and the end of the stars are studied through this. Asteroids are small celestial objects which orbit around the sun. The orbit of the asteroid is in between Mars and Jupiter. A comet contains small rigid material. This material is covered by substances with high masses.
Water, methane, and ammonia are the substances that cover the material. These substances are easily vapourised. It rotates the sun in an elliptical orbit and it keeps the distance high from the sun. The maximum distance it approaches the sun radiant energy of the sun heats the comet and vapourises materials contained in it. So it forms into a huge comet with a diameter of 10000km. The partially burnt pieces of the asteroids that fall on the earth are called meteoroids.
What is Asteroid?
Small planetary bodies orbit around the Sun are Asteroids. These Asteroids are in between the orbit of Jupiter and Mars. A Group of Asteroids in orbit is called Asteroid belts. It consists of millions of Asteroids. The asteroid belt contains almost 7,00,000 asteroids in it. Only 1600 asteroids are revolving around the Sun. 700km radius is the highest radius of the asteroid. It is named Ceres. It takes four and half years to circle the Sun. Asteroids apply a gravitational pull because of their huge size. So they didn’t have an atmosphere. Jupiter’s mass gravity and close encounters with Mars change the orbits of asteroids. Due to the close encounters with Mars, asteroids pulled out from the asteroid belt and roamed in any direction across the orbit of other planets. The name of an asteroid is given by the International Astronomical Union’s Committee on Small Body Nomenclature.
Fig:1 Asteroid hitting earth
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Composition of Asteroids
The composition of Asteroids is classified into three types. The distance from the Sun decides the composition of the asteroid. The difference in composition is dependent on the distance of the asteroid from the Sun. The oldest asteroids are C-type asteroids. It is a combination of silicate rock and clay. This asteroid has a very dark appearance. These are the most common asteroids. Metallic types of asteroids are a combination of nickeliron. These are called M-type asteroids. The nickel-iron and silicate materials combine and form S-type asteroids.
Types of Asteroid
Asteroids are classified into three types.
- Main Asteroid Belt − Group asteroids are known as asteroid belts. This asteroid belt is in the middle of the orbits of Jupiter and Mars. The asteroid belt consists of a million large asteroids and a million small asteroids. The average diameter of large asteroids is 1 kilometer.
- Trojans − Asteroids pulled out from the asteroid belt and in orbit with other planets are called Trojan asteroids. These asteroids do not collide with the planets. It has two special places in orbit. These two places are called Lagrangian points.
- Near-Earth Asteroids − These asteroids orbit close to the Earth’s orbit. Asteroids that cross the Earth’s orbital path are known as Earth-Crossers.
Characteristics of Asteroids
- There is no shape for an asteroid. But most of the asteroids are in a spherical shape that too have many shape-outs. Asteroids have rough surfaces and holes in their surface.
- It rotates the Sun in an elliptical orbit. But sometimes it rolls unevenly when it rotates against the Sun.
- Some asteroids have a small companion moon. Some asteroids have two companion moons.
What is Meteoroid?
When a comet reaches close to the sun it breaks apart into small pieces. While crossing the Earth’s orbit, these broken pieces fall on Earth. Because of the friction in the Earth’s atmosphere, some of the pieces are burnt. They are called meteorites.
A big piece from the broken comet will fall on earth when it crosses Earth’s orbit due to heat in the earth’s atmosphere. Some of the pieces are not fully burnt. These partially burnt pieces fallen on earth are known as Meteoroids.
Fig:2 Meteriod
Composition of Meteoroid
The meteoroid consists of silicates, oxygen, and some heavier metals. Iron and nickel are the heavier metals contained in meteoroids. These meteoroids are not broken. But some stone meteoroids will be breakable and have less density. A clash of two asteroids produces a meteoroid.
Characteristics of Meteoroid
The density of the meteoroid is higher than the Earth’s rocks. Because it consists of iron and nickel. Many meteoroids consist of a thumbprint shape of pits in them. There are no holes in meteoroids. The shape of the meteoroid is not round. It is also called shooting stars.
Difference Between Meteoroid, Meteor, and Comet
| Meteoroid and Meteors | Comet |
|---|---|
| The partially burnt pieces of the asteroids that fall on the earth are called meteoroids. | Comets are large objects consisting of lighter mass materials. |
| Meteor is visible without a telescope. | Some of the comets are visible to the naked eye. For example Halley’s comet. |
| It consists of oxygen, silicates, and heavy materials like iron-nickel. | It is a cosmic object consisting of water ammonia and methane. |
| A clash of two asteroids produces a meteoroid. | Comets are formed by the remaining frozen of the formation of solar systems. It consists of rock and ice or snow. |
Conclusion
Asteroids are small celestial objects which orbit around the sun. The orbit of the asteroid is in between Mars and Jupiter. A Group of Asteroids in orbit is called Asteroid belts. It consists of millions of Asteroids. A comet contains small rigid material. This material is covered by substances with high masses. Water, methane, and ammonia are the substances that cover the material. The broken piece of a comet falling on Earth is called Meteoroid. The moon, Mercury, and Mars have craters because the meteoroids hit the surface of these planets. A clash of two asteroids produces a meteoroid.
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