Asteroids as are small heavenly bodies, which move around the sun like the planets. Thus, they are also called planetoids. Most of theme go around the sun in the asteroid belt. Even comets, like Halley’s comet, which has been sighted many times in the sky,are small heavenly bodies.
They are characterized by a different orbit and a bright glowing tail. Meteorites are cosmic chunks of rock. when they enter the atmosphere, impact pressure causes the body to heat up and emit light, thus forming a fireball, also known as a meteor or shooting/falling star. They may occur very frequently.
What is asteroid belt?
The asteroid belt is the space between the orbits of Mars and Jupiter. In this area, billions of small rocky heavenly objects revolve around the sun, which are known as asteroids. The belt stretches only a few kilometers across. The asteroids originated probably at the same time as the planets. Possibly they are the remains of an ‘unsuccessful attempt’ to build a planet. Since they are very small, the asteroids can be thrown out of their orbit by a small collision. They can then fall on Mars or on the Earth.
When was the Halley’s comet seen the last time?
Halley’s comet mostly shines brightly and can be seen with the naked eyes when it is very close to the Earth. The last time this natural spectacle was seen in 1986. The comet is named after Edmund Halley who in 1696 declared that the comets viewed in the years 1531, 1607, and 1682 were the same. Its oval orbit around the sun brings it back to the Earth every 76 years.
Why do comets have tails?
Unlike the rocky and dusty asteroids, the comets are made up of a mixture of rock, dust, and ice. This is why astronomers also call it a ‘dirty snowball’. When the comet gets close to the sun, the ice evaporates and forms a cover of gas and dust around the comet. This is blown away by the solar wind, a stream of electrically charged particles, so that it gives rise to a long tail. This is also known as the coma. A few comets can be seen regularly from the Earth, while the others never come near our planet.
Why do we see shooting stars?
Shooting stars occur especially when the Earth in its orbit passes through a pile of debris of small rocky particles. Such ‘heaps’ are present near the orbits of comets because, after all, the coma of the comets partly consists of dust, and thus leaves behind a kind of ‘dust-track’.
The comet Swift-Tuttle leaves a trail of meteor showers known as Perseids, and when the Earth crosses this track we can see the meteors. At this time, up to 110 shooting stars can be seen every hour. Another such meteor shower takes place in November, when the Earth passes through the fragments of the comet Temple-Tuttle. This shower is known as Leonides.
What happens when meterite hits the Earth?
Meteorites fall on the Earth at ultrasonic speeds and leave behind craters, which are often 20 times bigger than the meteorite itself. Upon their impact, the rock is whirled up from the surface or melted and changed. The meteorite itself evaporates.
Only very large meteorites remain intact, such as the Hobe meteorite weighing 60 tons, which hit the Earth in 1920 in Namibia. Giant meteorites can throw up so much dust that the climate changes. Such a meteorite probably led to the extinction of dinosaurs 65 million years ago. Lonar Crater in Lonar, Maharashtra, India, is believed to be a result of a meteorite impact that occurred around 50,000 years ago.
Did you know…
Eskimos in the snow-covered Greenland extracted iron from the ferrous meteorites, which they found on the island?
The Shiva crater, sea floor structure located beneath Indian Ocean, west of Mumbai, India, was formed by a 40 km wide asteroid around 65 million years ago? It is named Shiva, after the Hindu god of destruction and renewal.
The tail of the comets is often millions of kilometers long?