How would we determine how life evolved on other planets?

Having said that, most exo-biologists start from the assumption that, if life does exist on other worlds, it may have arose in a similar process, and under similar conditions, as that on Earth; additionally, they assume that Darwinian evolution might at least partially apply on other planets. To date, we only have a sample size of life in the universe where n=1, so it is very difficult to generalize that the principles of biology that work on Earth may also apply on other planets.

Some biologists, however, believe that this approach might be overly restrictive and that we should be willing to consider the possibility that life may have evolved from silicon rather than carbon on other worlds.

Interestingly, some cosmologists have begun to suggest that the idea of evolution might also apply to some non-biological processes occurring in the universe. For instance, some contend that the physics constants that are commonly known as constants might actually be changing over time rather than remaining constant!

Scientists would employ techniques like examining the planet's atmosphere, looking for bio-signatures, examining surface characteristics, and making use of sophisticated telescopes and space probes to ascertain how life evolved on other planets.