The first Space Exploration occurred in 1957 with the launch of the very first artificial satellite, Sputnik 1, sent in to space by the Soviets. Since ancient times individuals have dreamed of departing the Earth and discovering other planets not known to man. Each era through history has developed a belief in regard to what the "heavens" are created form. The Greeks believed that the heavens and space were made from a material known as "Quietness", and other traditions once believed that the stars had been made of their own people who had died.
We now k now what stars are made of; they're made of numerous gases which explode again and again. Up until 43 years ago people could not travel in, nor even send objects into space. The most challenging part of traveling in space had been developing rockets which were powerful and dependable enough fling an object or people into space.
When speaking of space, objects that are frequently discussed are Comets and Asteroid's. A comet is basically, little, rocky, icy and also revolves around the sun. When a comet travels close to the sun, some of the ice turns to gas. This gas mixed with some dirty rock creates a lengthy, bright tail that points away from the comet.
If a comet where to hit our planet, it could trigger damage. Even if some thing relatively little in size striked the earth, it might cause significant damage. Little, from a comet`s point of view is something under 200 meters across. A comet that size hitting the Earth could wipe out an entire city.
Asteroid's are small or minor planets that move in what elliptical orbits. They are usually discovered between the orbits of Mars and Jupiter. They may be the debris of a planet that was destroyed by being hit by comets and then did not have enough mass to reform as a planet. Our current knowledge of space may not be as romantic as that of past civilizations, but it no less interesting.