Monday, March 12, 2012

Interesting facts about asteroids

Asteroids, also called planetoids, are small Solar System bodies orbiting the Sun.

The main difference between asteroids and planets is that asteroids never grew large enough to become planets.

In the orbits of the planets Mars and Jupiter is the largest group of known asteroids - the area known as the asteroid belt. It has been estimated that asteroid belt contains between 1.1 and 1.9 million asteroids larger than 1 km (0.6 mi) in diameter.

The first asteroid discovery in history occurred in 1801 with the discovery of asteroid Ceres, by Giuseppe Piazzi, though it was considered a planet at the time. Ceres is currently the largest known asteroid.

Astronomers at the University of Tennessee, Knoxville, believe that about 20 percent of asteroids have their own moons just like planets do.

The NASA scientists believe that giant black hole at the center of the Milky Way may be vaporizing and devouring asteroids.

In November 2011 an asteroid the size of an aircraft carrier safely flew past our planet. The next known approach of an asteroid this size will be in 2028.

The difference between asteroids and comets is that asteroids are rocks that primarily circle the Sun between the orbits of Mars and Jupiter while comets on the other hand tend to have highly elliptical orbits taking them from the frozen extreme edges of our Solar System to within distances so close to the Sun that solar radiation causes material in the comet to vaporize and stream out, forming the characteristic comet's tails.

The scientists study asteroids primarily because they believe that their samples might give them better clues in explaining our solar system's formation and how life began on our planet. This is the main reason why asteroids are the primary goals of many robotic missions.

Asteroids are in fact leftovers that originated from the cloud of gas and dust (the solar nebula). The solar nebula is believed to have collapsed to form our sun and the planets about 4.5 billion years ago. According to this theory asteroids contain the original material from the solar nebula, and can therefore provide us with the information about the conditions in times of our solar system's birth.

Huge asteroid hitting the Earth is one of the main themes of many Sci-Fi movies, This scenario could also at some time in future occur in reality, causing massive damage to our planet. Many scientists believe that the last time huge asteroid hit the Earth it killed all the dinosaurs and most other life on our planet.

The scientists are already looking at potential defensive systems against huge asteroids going our way. British scientists for instance believe that we should build large spacecrafts (so called gravity tractors) in order to stop large asteroids from hitting the Earth.