Although the thought of life on other worlds has become more popular in the last century, dominating the science fiction genres of film, television, and literature, the notion has been recorded for centuries. Man has always wondered what else is out there in the universe. If there is life here on earth, than that means there may be life elsewhere. Since the advent of modern astronomy technology, such as the Hubble telescope, one of the continuing projects of scientists all over the world is the search for planets that could, like earth,support life. After years of searching, scientists have released a general estimate for earth-like planets in our own galaxy: over two billion.
There are many, many factors that must be set in a specific way in order for life to exist on a planet. Most of the planets scientists find could are too hostile to support any kind of life. It takes the right temperature, distance from a sun, axis, and terrain to support life, along with many other more minute factors. While the planets scientists have found that can possible support life are in great number, this does not mean that life really exists on any of them. It will take many years of technology improvement in order for science to be able to fully explore other worlds, even from a distance. The thought of finding other forms of life keeps scientists going, and until they find something, science fiction will continue to expand our imagination regarding what that encounter would be like.