Use the links below to find out more about the Earth and Beyond at The University of Manchester...
The planet Earth is home to a huge variety of plants, animals and other forms of life but a big question which remains to be answered is:
So far we have sent several space probes to search for life on Mars. These have found evidence that liquid water was once present (thought to be needed for life to develop) but have not yet found any life. However we think that there is a good chance that primitive life (for example bacteria) may have once lived on Mars and perhaps may even still be living in sheltered spots protected from the harsh conditions on the surface.
Scientists don't think there is any chance of finding advanced life like plants and animals on any of the planets in our Solar System - green tentacled aliens with bug eyes don't live on Mars! However we now know that many of the stars we see in the sky their own families of planets. In our galaxy, the Milky Way, there are several hundred billion stars - that makes a lot of planets! Chances are that somewhere in our galaxy alien life may have developed. Perhaps when we look up at the stars with our telescopes, some "thing" is looking back at us through its own telescope!
The problem is we suspect there may be extraterrestrial (that word is usually preferred to alien, it means from outside the Earth and is often shortened to ET) life out there but how do we prove this. The stars are so far away there's no chance of visiting them in a spaceship, it would take many thousands of years to get there. One possibility is to send a message as a radio signal.
In fact the stars are so distant that even communicating by radio with ET would be a very boring affair. A message sent to even the nearest star would take four and a half years to get there. Any reply from ET would take another four and a half years to get back to you. Imagine the conversation:
In 2005 you say: "Hello is there anybody there?".
Nine years later, in 2014, you hear the reply: "Yes, this is Oomphlat the Tergissian, who are you?"
You say: "My name is Rebecca, I'm a human."
Another nine years later, in 2023, you hear: "What's a human?".
You get the idea - you're getting nowhere fast!
We think if anybody is going to send a signal it had better contain lots and lots of information to make it worth anybody listening out for it. In fact we have only ever sent one proper signal in the year 1974 - this was in the form of a picture made up of 0's and 1's.
The astronomers at Jodrell Bank have used their radio telescope to listen out for radio signals being sent by extraterrestrials who want to let us know they're out there.
We searched nearly one thousand nearby stars but unfortunately we didn't hear any messages. However we haven't given up and we're helping design and build a giant new radio telescope called the Square Kilometre Array (or SKA) which will do lots of interesting science including searching many more stars for signals from ET!
We hope that one day soon we may be able to answer that amazing question "Are we alone in the Universe?"
