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Comment by ejolto | Hacker News Reader

Do you mean terraforming Earth or Mars? Handling global warming will probably be easier than terraforming Mars.

Adapting to and/or fixing Earth's climate is easier than terraforming Mars by an enormous amount. Mars is more inhospitable to life than the center of Antarctica during the winter. Also, it's months away in a spaceship.

There's no scenario in which Mars is a viable alternative for the human race this century.

Earth. It's the same technology set, more or less, but aimed at cooling it down rather than heating up Mars.

I suppose the best option would be carbon capture, if it isn't too expensive, but I rather suspect it would be.

It is not too expensive if we were to use nuclear reactors to power it. (Yes, including hiked commissioning and decommissioning costs.)

Combined with solar and wind for peak of course because why not.

There are currently no other options. Renewables alone are not enough to even power civilization at current level. (They get somewhere shy of 60% in an impossible best case.)

easier scientifically != easier politically

just need to drop a few hundred thousand comets and asteroids and mars, and mar's moon, then float a few hundred thousand giant mirrors around it to warm it up a bit, seed it with plants, wait a few thousand years.

no big deal!

Don't forget solving the gravity disparity problem.

dumping the comets and moons onto the surface is to help with that. But I've done some napkin math and it looks like we need ~40 billion commets to bring it halfway to earth mass...welp

Makes terraforming Venus look easy.

If you crash the entire asteroid belt into Mars, its mass will increase by half a percent.

a good start! you can get most of that half of a percent with just the 4 largest asteroids.

maybe we need to sacrifice our own moon.

If we are moving the moon, we might as well just move the earth to a higher orbit further from the sun.

If we had access to this kind of energy, we'd be generating and treating copious amounts of antimatter and using it to power electrical CO2 sequestration devices.

Mars gravity, 38% of Earth's, doesn't seem like all that much of problem. Sure, there are some health risks associated with being in a low gravity environment. But considering humans survive surprisingly well in micro-gravity in space, I'm sure we can adapt to the relatively strong gravity on Mars.

> But considering humans survive surprisingly well in micro-gravity in space

Source for that claim? The number of studies I’ve read (as well as conversations I’ve had with astronauts) about the health impact on astronauts who’ve been on the ISS for extended periods seems to disagree.

Is less gravity the only difference in being on earth and being on the ISS?

Google would've easily found a bunch of supporting articles to what I stated, but here:

https://www.space.com/23017-weightlessness.html

https://science.nasa.gov/science-news/science-at-nasa/2001/a...

http://www.cnn.com/2016/05/20/health/your-body-in-space/inde...

https://www.nasa.gov/hrp/bodyinspace

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

tl;dr version:

> In space, without gravity, bones lose more than 1% of minerals and density per month.

> Astronauts also experience blood volume loss, weakened immune systems and cardiovascular deconditioning since floating takes little effort and the heart doesn't have to work as hard to pump blood through your body

> "It changes their visual acuity," Charles said. "They're not able to see things up close. It's like advanced aging. That sort of thing happens at a sort of an accelerated rate."

Why are you attributing it all to the lack of gravity? Losing muscle mass is one thing, but what about the increased high frequency deionizing radiation that astronauts face?

Because the scientists and medical professionals claim that it's related to the lack of gravity and provide evidence of why that is the case. Do you have a better approach, if so, why not publish based on your more knowledgable expertise?

https://www.sciencedaily.com/releases/2006/03/060322174351.h...

https://www.space.com/5245-long-space-missions-risk-cancer-p...

https://srag.jsc.nasa.gov/SpaceRadiation/Why/Why.cfm

All of those links are on radiation in space. The first two are as it relates to accelerated aging. These were not difficult to find.

Correct, but how does any of them counter what I said? They don’t!

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