We aren't going to populate the galaxy. We aren't even going to populate Mars. We are going to live on Earth until something cataclysmic happens, and then we will be gone.
200 years ago nobody would even think of flying on Earth, and yet here we are, taking it for granted that you can get almost anywhere on this planet within 24 hours for a couple thousand dollars, and within a century of inventing the car we landed a robot on freaking Mars.
Now I do think that we will take charge of evolution and invent a form of life that will be our successor to withstand a much harsher range of conditions and absent from the "bugs" of current life such as cancer and heart disease, rather than our current unreliable meat bags, but we'll make it happen nonetheless.
All that said -- I do want to see more attention toward terraforming Earth as well. Even with zero global warming, the sun's brightness will increase such that our oceans will boil away within 1 billion years, even though it won't actually engulf the Earth for another 4 billion. I would think it's realistic to extend the habitable period of life on Earth from ~300 million years to maybe 2 billion years with some terraforming tricks. That will buy us more time to terraform Mars or Saturn's moons in preparation for the red giant phase of the sun.
Also, learning to terraform the Earth can reverse global warming, because, you know, politicians don't give a fuck about stopping it, so we should attempt to learn to reverse it as a backup plan while the political environmental efforts continue in parallel.
And if we can cure cancer in the next 50 years (I think realistic), we'll have even better odds of surviving an event, as a species.
While we have the theoretical capability to destroy all plant life, I think realistically we'd end up obliterating a few cities before war would cease, and a full-on nuclear winter is unlikely.
I mean it's not really about what you think. See the top two links here about the devastating effects of small-scale conflicts
- https://doi.org/10.1038/d41586-020-00794-y
- https://doi.org/10.1073/pnas.1919049117
- https://doi.org/10.1126/science.222.4630.1283
- https://doi.org/10.1029/2019JD030509
This sounds wildly optimistic, considering our chronic inability to fix our behaviour before it results in excessive damage. Never mind the occasional asteroid.
> 200 years ago nobody would even think of flying on Earth, and yet here we are, taking it for granted that you can get almost anywhere on this planet within 24 hours for a couple thousand dollars, and within a century of inventing the car we landed a robot on freaking Mars.
The myth of Icarus is a bit older than 200 years. So are Leonardo da Vinci’s drawings. Plenty of people did in fact think of flying, most probably before they had any way of writing it down for us to read.