Question: What makes life possible on Earth?

Edward Bovill answered on 20 Mar 2013:

Astronomers are constantly looking for other star systems that are similar enough to our own that they could support life.

There is a very specific set of conditions that have led to life on Earth. Earth is just far enough away from the sun that we are at the right temperature for water to be liquid (most of the time), which is essential for life as we know it. Any closer and it would be too hot and water would boil, and too much further away and it would be too cold and water would freeze. The distance where Earth is is called the Goldilocks Zone as it’s not too hot or too cold, but just right.

Liquid water is essential to life as we know it, and combined with the other essential elements that are found on Earth (carbon, nitrogen, hydrogen, oxygen and others) life on Earth has flourished. Life may exist in other forms elsewhere in the Universe but we haven’t found it yet!

At the moment, scientists have been using the Kepler space observatory (a fancy telescope in space) to look for other planets in the milky way. This January, they estimated that there are over 17 billion Earth sized planets in the milky way alone. One of these planets, with the very catchy name KOI-172.0, is apparently in the Goldilock’s Zone around its star and is currently the best bet for finding alien life in our galaxy so far.