From the depths of space
MOST OF the DISASTERS WILL HAPPEN HERE IN earth. But in the depths of space, there are far greater sources of danger. Contrary to popular belief, space is not empty, it is full of objects moving at incredible speeds. Some of them are the size of a grain of powder, some of them – called asteroids – weigh millions of tons. If one of these giant rock fragments hits Earth, the result can be far more destructive than many atomic bomb explosions all over the world. Fortunately, this is unlikely to happen. The last hit of a giant asteroid on Earth took place millions of years ago, but no one knows if it will happen in the future. (Meteors, also called meteorites, are called meteorites when they enter the Earth’s atmosphere.)
The Destiny of the Planet
Millions of years ago, when a giant asteroid fell into Earth’s gravity and hit Earth with great force, it caused major changes. A large part of the asteroid crashed into the atmosphere of ash and stone clouds. These stones, probably overheated, oiled the earth and started fires. After the end of the stone rain, the dust covering the atmosphere prevented the sun’s rays from reaching the Earth and started a cold winter that would last for years.
In JANUARY 1801, AN ITALIAN ASTRONOMY saw a tiny spot of light between Mars and Jupiter. He discovered Ceres, the first known asteroid. Since then thousands of asteroids have been discovered around the Sun. Most asteroids move in orbit, so they stay at a distance from which they cannot be dangerous. However, each year a few asteroids emerge from orbit and the movement begins to progress in space at unbelievably fast speeds, which is the main problem.
A giant ring-shaped asteroid belt is the most populated part of the Solar System. A small number of asteroids are like small planets, but most are rock fragments less than 1 meter in length, most of the asteroids crashing together as the Sun rotates. When this happens, the asteroids are divided into smaller pieces and some of them begin to fall towards Earth.
Comets consist of rock, ice, and dust. As the Sun approaches, the ice melts to form a bright tail behind the comet. This trail disappears as we move away from the Sun and move deep into space.
Landing on EROS
In 2001, an unmanned research rocket landed on one of the largest asteroids orbiting Earth. Eros is 33 km long and has a weak surface. Although its density is much lighter compared to planets, it can cause tremendous disaster if it comes out of its orbit and hits Earth. Luckily, he’s been in the same orbit for too long, and it doesn’t look like it’s coming out.
RIGHT ON TIME
Unlike asteroids, each comet moves around the Sun according to a different time table. The most famous of these is the comet of Halley Comet which returns every 75 years. Halley’s next visit to the Hale-Bopp Comet, which will take place in 2061, is much longer. Hale-Bopp won’t be back until 4380.