Question: How long do you think it will take to terraform and colonize mars?

Duncan McNicholl answered on 8 Nov 2017:

First we’ll have to invent terraforming, and that sounds pretty hard: the earth is kind of pre-terraformed, so we’re lucky there. I know that Elon Musk wants to send the first visitors to mars in the next five or ten years, but the first visitors will be a long time before the first colonists, and I think there’s a long time between the first colony and when we’d say we’d colonised mars. I reckon hundreds of years for colonisation and maybe thousands before we know how to terraform it.