G
grayure
Guest
Yes, in two different ways. Aliens are likely to have visited the planet in the past and technological cultures have evolved from native life as well, for example coleurosaurs. The problem with this, though, is the paucity of evidence, and this is a rationalistic rather than scientific position, justified thus. Earth has existed for nearly five billion years and the Galaxy for about twice as long. The number of suitable environments for the evolution of technological cultures is huge and it is therefore very likely that this planet has been visited in the past. Besides this, there have been times in Earth's history when certain species have converged with human characteristics, two of these being the coleurosaurs in the late Cretaceous and the oreopithecines about 30 million years ago. There are also supposedly a few fossilised artefacts dating from millions of years ago. However, i have to admit that this sounds crazy and is not backed up by empirical evidence.