Frank, as my team suggested, in 2009 NASA’s Kepler telescope began pointing at a small patch of sky for four years. In that time it found a series of stars with Earth like planets surrounding them. If you multiply this little bit of the sky to cover the whole Universe you are talking about over 50 billion Earth like planets. A good assumption would be that some form of life found it’s way to existence on some of them. Maybe they have yet to develop, like us, a way of communicating over the great distances involved.
If you are a teacher read the following Guardian article Updated 26/02/2017