Can collision of a planet with a large comet or asteroid occur?
Large comets or asteroids are rare phenomena now and hence the possibility is remote. However, such large bodies were abundant in the early history of the Solar System and there is evidence that major catastrophic collisions did occur. Craters and basins hundred or even thousands of kilometers in diameter have been observed on the Moon, Mars and the large satellites of Jupiter. A large comet or asteroid colliding with a small planet or moon can even completely shatter it. Mimas, one of the moons of Saturn, seems to have barely escaped being completely shattered by such a collision but only half of the original moon exists and the other half has been shattered.
Name a recent planet-comet collision.
In July 1994, the comet Shoemaker-Levy-9 collided with Jupiter. The comet split into fragments before impact, and was closely monitored from Earth and space probes.
Is there any possibility of a comet colliding with a planet like the Earth?
There is a possibility that small comets, or small fragments of large comets, may fall on a planet provided the bodies are close and the gravitational pull is appreciable enough. In such cases, it is likely to burn up in the atmosphere sometimes even resulting in a powerful explosion before the comet hits the Earth.
Has a comet fragment actually hit the Earth in Modern times?
An unprecedented explosion occurred on 30th June 1908 in the largely uninhabited Tunguska valley in Siberia and was heard up to 14,000 km away. At the explosion site neither was there any crater nor signs of impact but the trees around over an area of 3000 sq. km were flattened. Obviously, it must have had the force of a 2 megaton atom bomb. But no atom bombs existed at that time. Could it have been an exploding comet fragment?
What would happen if a comet collides with the Moon?
Since the Moon has no atmosphere, the comet wouldn’t burn up but would directly hit the surface of the Moon. At the point of impact, a crater would be formed. Such craters can be seen on the Moon even with the naked eye. Even in planets like Earth with an atmosphere, impact craters of comets do occur if the comet did not explode or completely burn out before reaching the surface of the Earth. Such an impact crater has been found at Lonar near Pune in Maharashtra.
Are all craters the result of cometary impacts on Earth?
Craters can be caused by impact of comets or asteroids. About a third of the craters on Earth are caused by long period comets and the rest by asteroids. In the case of those observed on the moons of Jupiter, half are caused by asteroids, a quarter by long period comets and the remainder by short period comets.
Is there a possibility of a large comet colliding with the Earth?
There is some evidence that large comets of about ten kilometers in diameter have hit the Erath in the past creating craters of more than 100 km in diameter. Three such craters have been identified on Earth, and there may be some more on the sea beds. If a large comet hits the Earth it would annihilate most species on Earth. There is evidence of periodic large-scale destruction of planet and animal life on Earth through such collisions.
Which are the comets or asteroids most likely to collide with the Erath?
Some asteroids called Earth grazers regularly pass close to Earth. Asteroid Hermes has passed within 77,000 km from Earth. Other smaller objects may also graze or collide with the Earth. However, with advances in technology, scientists might know well in advances in technology, scientists night know well in advance of any comet or asteroid likely to collide with Earth and deflect or destroy then using rockets and nuclear bombs.