Therefore, having multiple independent communities on other planets as well as other solar systems will decrease the chances of the extinction of all of mankind (Catastrophes and Human 1-2). It is necessary to explore and colonize space to ensure long term survival of the human race.
Space might seem silent, but it is not always peaceful. The stray asteroids and wandering comets in our solar system sometimes cross paths with a planet having a devastating effect on it. The Earth is not immune to such impacts. Giant impacts could have severe and grave consequences on the life on Earth. Most scientists now accept the theory that a ten kilometer asteroid crashed into Earth 65 million years ago killing off more that half the species of life on Earth including the dinosaurs. If such an impact were to happen today, it could very well spell the end of the human race (Bang and Splat 1).
On March 2002, a seventy meter long asteroid flew near planet Earth without anyone noticing until after it had passed. Scientists said that it was in an astronomical blind spot. The asteroid passed by Earth within 288 thousand miles - just a little longer than the distance to the moon - on March 8, but because it came from the direction of the sun, scientists could not see it until four days later. This object was slightly larger than the one that flattened the Siberian forest in 1908 and was one of the ten closest known asteroids to approach Earth. If Asteroid 2002 EM7 would have pierced the atmosphere, the seventy meter long asteroid could have disintegrated and unleashed the energy of a four megaton nuclear bomb. If it would have been over a highly populated city, like Atlanta, it would have basically flattened it (Whew 1).
Scientists are now saying that a large asteroid will miss Earth by only 38 thousand kilometers in 2027. This is going to be a close one. The Moon orbits ten times further that distance from the Earth.