Our first search for life else where? Mars!
All together:
10 missions have gone to Mars (beginning in the early 1960s)
4 are currently studying Mars (Spirit and Opportunity!)
5 are currently scheduled for the future.
Viking 2 scooped up bits of Martian soil and tested them for the presence of life and organic molecules. Despite tantalizing initial results, the Viking experiments suggest that Mars is, at present, a dead world. But a billion years ago, Mars was more warm & wet..
100 years ago, most people assumed life existed on Mars!
This was due to Percival Lowell's work --->
However, even today, outside of the Earth, Mars appears to be the most likely place for life in the Solar System. In fact, it can almost certainly be assumed that material from Earth has made it to Mars, thereby `infecting' it.
Extra-solar Planets
More recently, in 1995, evidence of a planet orbiting another
star was found. Today, more than 100 extrasolar planets
have been found, and more
are found nearly weekly (see exoplanets.org).
The discovery of these `planets' have had a profound effect on current scientific
investigations.