strike wolf wrote:Really on earth we had the optimal conditions for life.
For human life. A planet made up entirely of water, for example, could spawn aquatic life. A planet with tremendous gravity could produce small, multilegged life. And so on...
Any manner of lifeforms are possiblities. If it hadn't been for the meteor strike, there might be a race of sentient beings that evolved from the dinosaurs.
Earth has optimal conditions for our existence, but it's not the only type of planet that can sustain life when you take into account that lifeforms could adapt and evolve to any climate with the right starting materials. We're carbon-based, but life could exist elsewhere that's nitrogen-based or copper-based or what have you.