Are we alone in this universe? Does life exist in other planets? These are the kind of questions that are yet to be answered. Within the last 100 years scientists have shown remarkable advancement in space science. Millions of dollars are gone and a lot of time has been spent to answer the above questions. Space telescopes have brought us pictures of unknown planets that might have some indication of life like that of the Earth. But we are unfortunate to say that out of the nine neighbor planets, life exists only on Earth. What is magical about Earth that makes life possible here? There's lot of scientific details that concl