If you want a backup, why use Mars?

You can create habitats from scratch, or you can have colonies on the moon.

Even Mercury is better than Mars.

somenameforme 3 days ago | parent | next [-]

Lots of reasons for this. The Moon is a complete hell hole - 2 week long nights, night time temperatures that drop to around -200f, daytime temperatures in excess of 250f, extremely low gravity (to the point that one might expect a higher impact of the countless health consequences of 0g exposure on humans), minimal material resources and so on. There is also no atmosphere at all which complicates landing, means even the smallest micrometeorite will impact the surface (which is why the Moon looks like it does), and contributes to highly dangerous particular dust everywhere - much worse than than on Mars.

By contrast Mars is bizarrely similar to Earth. It has almost identical axial tilt resulting in a similar seasonal cycle, a similar annual cycle, extensive mineral resources, some atmosphere simplifying landing - providing protection from meteorites, etc. It has temperature ranges that, like Earth, vary wildly due to seasonality, but are locally consistent. For instance on a summer day near the equator, it hits about 20C on Mars. If not for the blood boilingly low atmosphere, it'd be down right comfy.

Anyhow, kind of a rambling disorganized comparison because I'm in a rush - but yeah, Mars is almost eerily Earth like. In that if life was a video game Mars would be the kind of obvious 'next level', to a degree that makes it feel scripted. Even some chemical reactions like the Sabatier Reaction [1] (Martian atmosphere + electrolyzed ice => methane + oxygen + water) just feel too convenient to be true, but they are.

[1] - https://en.wikipedia.org/wiki/Sabatier_reaction

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eru 3 days ago | parent [-]

> Lots of reasons for this. The Moon is a complete hell hole - 2 week long nights, night time temperatures that drop to around -200f, daytime temperatures in excess of 250f, extremely low gravity (to the point that one might expect a higher impact of the countless health consequences of 0g exposure on humans), minimal material resources and so on.

Dig a bit, and temperatures even out. Same as on Mercury.

About the light: you are going to stay indoors anyway.

About gravity: spin! You can build something that looks a bit like a giant funnel, spin that, and live on the inside. If you set up the speed of rotation and degree of incline right, the centripetal force and the moon's gravity will combine to point perpendicular to the surface you are standing on.

You are right that Mars has some interesting peculiarities. But the logistics are a million times harder than getting to and from the moon. So good luck getting a rescue mission there.

In addition, I would advice against contaminating Mars with earth life, if we still want to study it, and figure out if it ever had life. (The moon is and always has been almost certainly sterile.)

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somenameforme 3 days ago | parent [-]

With radical ideas it's likely that anywhere can become habitable - there have even been ideas to create floating cities in the thick atmosphere of Venus. But places that require esoteric and ever more complex solutions are obviously less desirable than those that don't. And Mars is 100% 'easy mode' in terms of our first colonization outside of Earth.

	▲	eru 3 days ago \| parent [-]
		Yes, the higher atmosphere of Venus is surprisingly habitable. You call Mars 'easy mode', but you can fill (acid-proof) balloons with Earth atmosphere, and they will float in Venus at more or less exactly the spot that has a nice temperature and pressure for humans to enjoy.

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JumpCrisscross 3 days ago | parent | prev [-]

> Even Mercury is better than Mars

...how? It's further. It has no atmosphere. There is no water or carbon.

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eru 3 days ago | parent [-]

How is Mercury further? On average it's the closest planet to earth.

Mars's atmosphere is pretty useless for humans.

	▲	addaon 3 days ago \| parent \| next [-]
		> How is Mercury further? Δv, the only metric that matters. Mercury is at 5.5 km/s from LEO, vs 3.6 km/s from LEO for Mars.
	▲	thaumasiotes 3 days ago \| parent \| prev \| next [-]
		To be fair to JumpCrisscross, he never claimed Mercury was further away. It's just "further".
	▲	JumpCrisscross 3 days ago \| parent \| prev [-]
		> Mars's atmosphere is pretty useless for humans Oxygen, carbon, nitrogen and hydrogen make up 95+ percent of a human by mass. Mars has all four, the first three in the atmosphere.