I suppose the main counterargument would be that we only need the Mars colony for the case of Earth getting hit by an asteroid and losing all large mammals, including humans. The Marsians would then somehow survive without supplies coming from Earth, wait until the situation on Earth has normalized, and then use a spacecraft with some fuel left to colonize Earth again. Humanity maybe saved.
Space colonization is all very well. The point with this article is that Mars in particular is a very bad place to colonize. If we only want space colonies the natural choice is to place them in free space, as rotating habitats in the Gerald K. O'Neill mold (which I wrote about here: https://woodfromeden.substack.com/p/up-where-we-belong ). The only thing Mars has that free space lacks is materia, but since that can be imported from the asteroid belt or many other objects in space it is not really a limitation.
By now you probably can tell I'm making my rounds through Wood From Eden; this is a wonderful blog, and I hope my comments will stimulate further readers to participate. The reason I took so long to get around to reading this particular essay was because I agreed with it beforehand. Mars is a terrible destination for colonization and will be for the foreseeable future, and everything you say is (or jolly well should be) well known among physicists, even if the general public doesn't really understand it. The only comments I can make are quibbles or asides, but here they are:
Weak sunlight is a very minor issue. Nuclear power is already most efficient for providing electricity even on Earth, and its potential for improvement is far better than solar power - I think we can reasonably expect fusion reactors within the next hundred years.
Weak gravity, by contrast, is an absolutely enormous issue.
Firstly, planets with gravity significantly weaker than that on Earth cannot retain water in their atmosphere: https://en.wikipedia.org/wiki/Atmospheric_escape . This means that Terraforming, and sustainable surface agriculture, will never be possible on Mars. Life will be confined to biospheres. Do note that the glass on these biospheres would turn them into greenhouses, raising temperatures to useful levels. And, since the limiting factor of plant growth on Earth is (surprisingly!) not sunlight, but rather warmth, crops could reasonably be expected to thrive on Martian Biospheres, growing to extreme heights in the low gravity. Speaking optimistically, there could be a market for enormous Mars-grown produce, though the shipping costs of course would be astronomical.
Secondly, humans do not thrive in low gravity environments. Although any level of gravity can be simulated in space stations by rotation, it would be highly expensive and likely quite dangerous to create a rotating station on Mars to amplify the weak Martian gravity. More likely people would wear weights and make use of magnetized footwear to improve maneuverability and stave off emaciation, but it's hard to imagine that most people would want to move to Mars knowing that over time their bodies would grow flabby, unappealing, and too weak to return to Earth. Again, speaking optimistically, it might be appealing to the bedridden, wheelchair-bound, and morbidly obese; but when people came to associate Martian living with the rich and physically disabled, the mystique of faraway living beneath Phobos and Deimos would quickly sour.
Lastly, there are alternative environments much closer to home which do not lack these disadvantages. Life in polar biodomes, or in aquatic bubbles, would be much cheaper (no need to escape Earth's gravity well) and safer (help is never more than 20,000 km away). Submarine living in particular could be attractive, as the water would maintain moderate internal temperature, offer access to fish from outside the bubble, and even allow for mobility - imagine a submarine colony that followed currents to different oceans at different depths throughout the year, allowing people to enter or leave an aquatic city from countries all across the dry land surface of the Earth. Mars cannot compete with that.
I more or less agree with you on everything in this comment.
However, are you sure about the sunlight? Nuclear power is of course competitive compared to solar panels. But most of the vast amounts of sunlight humanity uses is not for making electricity but rather for agriculture.
While
nuclear power -> electricity
is more efficient than
sunlight -> solar cells -> electricity
I doubt that
nuclear power -> electricity -> LED lights -> agriculture
is more efficient than
sunlight -> agriculture
Given this I still think weak sunlight is a real limitation since agriculture is of such paramount importance to humanity. I imagine a human civilization in any dark place would have to spend an inordinate share of resources to produce enough electricity and LED lighting to feed themselves.
My good man, I'm really not sure about anything. Taking care not to be sure is important to me; the closest I ever become to being sure about something is being bored to tears of wondering about it.
But what I meant with my comment was that, while weak sunlight is a problem, low gravity is an absolute deal-breaker. The fact that water would evaporate from the Martian surface into space kills any hope of Mars being more than a place to put biospheres. We can put those in Antarctica, or in the shallow regions of the ocean. If we're going off planet, probably smarter to put them on Ceres, or just leave them free-floating amidst the asteroids of the main belt.
I suppose the main counterargument would be that we only need the Mars colony for the case of Earth getting hit by an asteroid and losing all large mammals, including humans. The Marsians would then somehow survive without supplies coming from Earth, wait until the situation on Earth has normalized, and then use a spacecraft with some fuel left to colonize Earth again. Humanity maybe saved.
Space colonization is all very well. The point with this article is that Mars in particular is a very bad place to colonize. If we only want space colonies the natural choice is to place them in free space, as rotating habitats in the Gerald K. O'Neill mold (which I wrote about here: https://woodfromeden.substack.com/p/up-where-we-belong ). The only thing Mars has that free space lacks is materia, but since that can be imported from the asteroid belt or many other objects in space it is not really a limitation.
By now you probably can tell I'm making my rounds through Wood From Eden; this is a wonderful blog, and I hope my comments will stimulate further readers to participate. The reason I took so long to get around to reading this particular essay was because I agreed with it beforehand. Mars is a terrible destination for colonization and will be for the foreseeable future, and everything you say is (or jolly well should be) well known among physicists, even if the general public doesn't really understand it. The only comments I can make are quibbles or asides, but here they are:
Weak sunlight is a very minor issue. Nuclear power is already most efficient for providing electricity even on Earth, and its potential for improvement is far better than solar power - I think we can reasonably expect fusion reactors within the next hundred years.
Weak gravity, by contrast, is an absolutely enormous issue.
Firstly, planets with gravity significantly weaker than that on Earth cannot retain water in their atmosphere: https://en.wikipedia.org/wiki/Atmospheric_escape . This means that Terraforming, and sustainable surface agriculture, will never be possible on Mars. Life will be confined to biospheres. Do note that the glass on these biospheres would turn them into greenhouses, raising temperatures to useful levels. And, since the limiting factor of plant growth on Earth is (surprisingly!) not sunlight, but rather warmth, crops could reasonably be expected to thrive on Martian Biospheres, growing to extreme heights in the low gravity. Speaking optimistically, there could be a market for enormous Mars-grown produce, though the shipping costs of course would be astronomical.
Secondly, humans do not thrive in low gravity environments. Although any level of gravity can be simulated in space stations by rotation, it would be highly expensive and likely quite dangerous to create a rotating station on Mars to amplify the weak Martian gravity. More likely people would wear weights and make use of magnetized footwear to improve maneuverability and stave off emaciation, but it's hard to imagine that most people would want to move to Mars knowing that over time their bodies would grow flabby, unappealing, and too weak to return to Earth. Again, speaking optimistically, it might be appealing to the bedridden, wheelchair-bound, and morbidly obese; but when people came to associate Martian living with the rich and physically disabled, the mystique of faraway living beneath Phobos and Deimos would quickly sour.
Lastly, there are alternative environments much closer to home which do not lack these disadvantages. Life in polar biodomes, or in aquatic bubbles, would be much cheaper (no need to escape Earth's gravity well) and safer (help is never more than 20,000 km away). Submarine living in particular could be attractive, as the water would maintain moderate internal temperature, offer access to fish from outside the bubble, and even allow for mobility - imagine a submarine colony that followed currents to different oceans at different depths throughout the year, allowing people to enter or leave an aquatic city from countries all across the dry land surface of the Earth. Mars cannot compete with that.
I more or less agree with you on everything in this comment.
However, are you sure about the sunlight? Nuclear power is of course competitive compared to solar panels. But most of the vast amounts of sunlight humanity uses is not for making electricity but rather for agriculture.
While
nuclear power -> electricity
is more efficient than
sunlight -> solar cells -> electricity
I doubt that
nuclear power -> electricity -> LED lights -> agriculture
is more efficient than
sunlight -> agriculture
Given this I still think weak sunlight is a real limitation since agriculture is of such paramount importance to humanity. I imagine a human civilization in any dark place would have to spend an inordinate share of resources to produce enough electricity and LED lighting to feed themselves.
> are you sure...
My good man, I'm really not sure about anything. Taking care not to be sure is important to me; the closest I ever become to being sure about something is being bored to tears of wondering about it.
But what I meant with my comment was that, while weak sunlight is a problem, low gravity is an absolute deal-breaker. The fact that water would evaporate from the Martian surface into space kills any hope of Mars being more than a place to put biospheres. We can put those in Antarctica, or in the shallow regions of the ocean. If we're going off planet, probably smarter to put them on Ceres, or just leave them free-floating amidst the asteroids of the main belt.