I was watching a program recently which contained an article about whether or not UFOs existed and if they are piloted by extraterrestrials. One of the arguments used against both their existence and their presence here was “Why would they come here? Why cross the reaches of space (even if they can) and come to Earth?”
Well, it occurs to me that they might do it for the same reason that we are sending probes to Mars, Jupiter, etc. To find out what is there and to see if these places could support life now, or in the past. If an alien civilisation sent a probe here – using technology that circumvents the problems associated with surpassing the speed of light – and that probe found signs of life, would it not stand to reason they would want to come here themselves. After all, if one of our probes was to find life on Europa, for example, would we not want to drop in for a visit and see it for ourselves?