What other things have humans accomplished that are even 1% of 1% of the magnitude of colonizing Mars?
The cost of establishing a Mars colony is somewhere between $1 and $100 quadrillion. By contrast, building the US interstates, a big project by human standards, cost about half a trillion in today’s money.
If we had all the time in the world, sure. But we don't. We don't even have 50 years.
Our planet is dying under us right now. This is the most pressing issue in human history and we're seeing the consequences of our relentless fouling of our own environment every single day, and yet each day the catastrophe accelerates.
Imagine a man are in a burning house with their family, but instead of fleeing, he is on the computer, arranging for his great-grandchildren's retirement fund. This is what we, humanity, are doing by dreaming of Mars and ignoring the Earth.
For forty years, people have responded that we have money to do both. But we aren't actually doing either.
It would cost quadrillions of dollars to colonize Mars, and the result would still be an inhospitable and resource-poor world.
Why would anyone do actually this? Move to a planet where they’d be incredibly poor for centuries, poor in even the simplest things that humans take for granted, like trees and grass and fresh air and water and sunlight, and spending all their time fighting for survival, where any minor mistake would kill you? No one who advocates for this really thinks it through and understands how truly awful and grim life would be for Mars colonists, for no obvious benefit to them every at any time in their future.
Mars’ average temperature is -60ºC, and even if it were terraformed through a feat of engineering orders of magnitude greater than all other civil engineering feats in history put together, the temperature isn’t going to go up very much, because Mars is simply a long way from the Sun.
It’s a nice day. Right now, I can walk out my door and walk as far as I please, right into woods and fields and rivers. This is no great accomplishment, but it will never, ever be possible on Mars.
For tens of trillions of dollars, we could prevent the devastation of our biosphere, whose worth is by any rational evaluation thousands of times that of Mars. (Just the water and oxygen alone!)
The murder of our biosphere would be by far the greatest crime ever committed, literally greater than all other crimes put together. Fleeing to Mars to escape the consequences of The Greatest Crime is just an evil fantasy.
