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Asteroids






Asteroid or the “killer rock” is a small solar system body, whose size varies from a planet to a meteoroid. The smaller ones are called as “minor planets” and the larger ones are called as “planetoids”.

The size of an asteroid varies from 1000 km up to 1 meter. These asteroids together form an Asteroid belt and orbits around the Sun. This asteroid belt is between Mars and Jupiter and has elliptical orbit. Some scientists believe that asteroid belt is remnants of a planet which was destroyed in the collision whereas others believe that they are material left from a planet which was never formed due to Jupiter’s gravitational force. 


How are they formed?

There are three types of asteroids:  Carbon type, silicate type and metallic type.  The core of asteroid is either rocky core, nickel-iron core or carbonaceous core; depending on their composition.  The process of asteroid formation can be widely seen as a contrasting process, as we are not quite sure about its composition. Consider Ceres-the first asteroid discovered-has spherical structure and carbonaceous composition. But if Ceres is compared to Ida (a bit smaller asteroid than Ceres), Ida has irregular shape and heavily composed of iron and magnesium-silicates (silicate type).

What is the difference between comet, asteroid and meteoroid?

Many confuse asteroid with comet and meteoroid.  The major difference between asteroid and comet is of composition. Asteroid is made of mineral and rock; whereas comet is made of dust and ice. Asteroid is formed in vicinity to the sun. When comet is in the vicinity of the sun, the ice melts and we see the icy-white tail behind it.
The difference between meteoroid and asteroid is of size. Meteoroid is smaller than that of asteroid and orbits either around the sun or other bodies in space. Finally meteoroid can be made up of either cometary material or asteroidal material.

 What happens if asteroid hits the earth?

It is a very rare incidence for Earth to get hit by an asteroid. The last time this happened was 100 million years ago, when a large sized asteroid hit Earth and wiped out the majority of dinosaurs, thus causing extinction for the species.  However, there are many evidences that suggest that lesser-sized asteroids have hit the planet. There are various craters on Earth which prove their collision. However these collisions have occurred millions of years ago. There are no such recent events.

Can asteroid be used as an energy resource for earth?

Many are working on this idea of using asteroid as an energy resource. Since the resources on earth are becoming scarce very rapidly, we have to find more ways to fulfill our energy needs. Asteroid Mining is one way of doing it. Asteroid has carbon, silicate and other metallic contents which can be used as an energy resource. Gold, silver, palladium, platinum tungsten etc. can be brought back to earth. Iron, cobalt, magnesium can be used in construction and hydrogen, ammonia and oxygen can be used to prepare rocket propellant. There are three ways in which asteroid mining can be performed:
  1.           Bring back the raw material from asteroid to Earth.
  2.          Process the raw material on site and bring back the processed materials.
  3.        Shift the asteroid to safely orbit around Earth, Moon or ISS. This is a hypothetical method         which will allow most of the materials used.  NASA is still working on this project. This           mission is called as “Asteroid Redirect Mission”.


Mining can be performed by using various techniques like surface mining, shaft mining, heating etc.  There are many projects which are proposed to help in asteroid mining. Each project is checked for its financial feasibility and safety. There are many ongoing and planned missions for asteroid mining. If it works, it will help to overcome our resources scarcity and hopefully fulfill our needs!




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