I agree that colonizing another world is important as a "backup policy" but I'm still skeptical that Mars is inhabitable in the long term with current technologies. I feel like human civilization would have a better chance of surviving deep underground or in the oceans than spending so many resources attempting to colonize Mars.

> I'm still skeptical that Mars is inhabitable in the long term with current technologies.

Then the Moon is, as well.

I would argue the moon is more difficult than Mars to colonize. No atmosphere means landing will always be, at best, a giant pain in the ass, and at worst, extremely dangerous. A lack of water of any kind makes life nigh-on impossible, as well as the moon's extremely long days; Imagine being in the sun (albeit at a toasty 100C or something, but whatever) for fourteen days straight, followed by the longest, coldest night you've ever experienced (to the tune of -120C or worse) for fourteen days straight. That would be a nearly insurmountable engineering feat in and of itself, totally neglecting the other problems.

I think Mars will ultimately prove much easier to colonize. Getting there isn't necessarily hard once we've figured it out; we have the life support systems to keep the ISS going (albeit with constant support from the ground) for 15 years, and we can already do all the orbital math and whatnot. It's just a matter of doing it.

In general, I agree.

Temperature changes will likely be dealt with by living underground, and there's something to be said for the ability to nope out of there in a couple days instead of months/years.

I think there's value to figuring out both - a giant space telescope on the far side of the Moon would be amazing for science - but Mars seems like the more logical first spot.

Putting a semi-permanent colony on Mars is cheaper than you might think, on the order of $50 billion [1]. That's about 10 aircraft carriers, or 1/3 of the cost of the ISS. Making it independent of the Earth is of course orders of magnitude more expensive, but making a self-sufficient underground habitat on Earth isn't exactly cheap either.

https://en.wikipedia.org/wiki/Mars_Direct

I'm pretty sure a nearby gamma ray burst would sterilize the whole solar system.

I was under the impression that it is not the gamma rays that would get you but the destruction of the ozone layer [1].

1. https://en.wikipedia.org/wiki/Near-Earth_supernova

Mars doesn't have an ozone layer, so it's not clear that it would be more inhabitable than Earth with a degraded ozone layer. Even if we had to live underground for a while and lots of things died, we'd still be breathing oxygen and using tools that already exist here.

There is water (ice) on the moon at the poles and carbon in the rocks so it would be possible to make rocket fuel. Wanting to colonise Mars does not mean you should avoid the moon.

Edit. Spelling

> There is water (ice) on the moon at the poles and carbon in the rocks so it would be possible to make rocket fuel

Both requiring advanced, energy-intensive chemistry to extract small amounts of water and trace amounts of carbon. All running on specialised gear built out of elements difficult to find on the Moon. Compare that to heating a fluid containing 95% CO2 to 400 degrees C and running it over a catalyst which makes up over 5% of Martian soil (aluminium).

> Want [sic] to colonise Mars does not mean you should avoid the moon.

There's value in focus. Mars is the easier and superior target, given present technology and Elon's goals. Someone else can focus on the Moon if they want to.

I am not sure Mars is the easier target given how much further it is up the gravity well, but certainly Elon is welcome to focus on whatever he wants. I was just making the point that the Moon is able to be used as a source of rocket fuel if so desired and in my opinion it is a worthy target.

Interesting point. Do you think Elon Musk would ever create a expedition to the Moon even though he's so focused on Mars right now? I always thought he would've tried at least once

Von Braun wanted to go to Mars too, but ended up choosing the Moon as being the more viable option.

Yeah, in the 60s when nearly every occurrence in space was a "world first"

> Want to colonise Mars does not mean you should avoid the moon.

But does going to the moon do anything to further the cause of colonising Mars? Elon has specific goals he is pursuing. Going to the moon would consume resources that could otherwise be used going to Mars, and there's nothing useful he could do on the moon that would help him in his actual goals.

Right, so a perfect starting place to test things out, instead of going to mars straight away