1. Security Problem: A large asteroid can hit earth. In past dinosaurs had been wiped out because a giant asteroid hit earth. Global warming is melting all our glaciers. Ocean waters are rising. This will probably flood our planet. Solar Flare can burn our shelter and food supply. Many such events can destroy human race. Solution: If we will have a secondary planet colonized, human race will survive. Basically if there are eggs in two baskets and one burns down, the other basket will be there to hatch the eggs. 2. Resource exhaustion Problem: Human's population is rising. Humans are absorbing many resources Running low on resource: food, water, oxygen and shelter. Humans need to have second planet for more resource. Solution Mars has water, some air, and the sunlight. We humans can go start small colonies soon. Then we can g...