Is establishing a colony 12 light years away easier than transforming mars into a habitable planet?
And for terraforming Mars, Isaac Arthur’s YouTube channel has many related videos, and he posits that by the time your civilisation could do it, it would be a wasteful use of Mars when it could be better disassembled and turned into O’Neill cylinders or something.
But coming over a crater or valley on Mars and transforming it into something habitable would be enormously easier than travelling 12 ly.
I'm not convinced this is true intergenerationally without a maternity ward in a centrifuge; the low gravity mouse embryo experiments don't look promising. Maybe 1/3rd earth gravity is enough, but I'm doubtful. If we're granting centrifugal habitats as something doable with current technology, an Orion/Daedalus style nuke-propelled spacecraft seems in the same ballpark. It's been sketched out and tested with models, it's clearly possible, but nobody has really made one yet and it's a hell of an engineering problem still.
And there's no one there to raise them if you did.
The diameter of the Moon is 2,160 miles. The diameter of Phobos is 14 miles. Deimos is 8 miles.
(For scale, Mars' diameter is 4,200 miles).
There is a chance that nuking the polar caps would terraform Mars, I think we already have the technology for basic terraforming.
edit: wrong quote :/