> Most plausible post-apocalyptic Earths would be far easier to live on than Mars.

thank you

how are we supposed to build a second home on a dead, ruthlessly hostile planet until we demonstrate ourselves capable of stabilizing the biosphere and building a sustainable long-term civilization here

Earth is easy mode compared to Mars

> how are we supposed to build a second home on a dead, ruthlessly hostile planet until we demonstrate ourselves capable of stabilizing the biosphere and building a sustainable long-term civilization here

Because we can afford to make big mistakes in terraforming a dead, ruthlessly hostile planet.

A few microscopic fungal-like spore things could throw a wrench in that. Now the planet is a nature reserve.

why?

fungel spores probaly are contaimination by what ever probe we sent there. any life evolving their would not be from any terrestrial evolutionary branch such as fungus

All this terror about "contaminating" other objects in the solar system with terran life is just misguided. We should all hope to get some terran life established on them.

Heck, we need to build probes full of selected terran extremophiles and spray them into the Martian atmosphere.

1. Any existing life there is, at this point, highly improbable

2. If there is any, how could terran life be competitive with it if the existing life has evolved to match the local environment over billions of years?

3. If there is existing life, how could a biologist not be able to easily distinguish it from terran life?

4. If the life there is ancient and now extinct, terran life isn't going to interfere with that

To answer part 2 with just one example: The native life of Mars, if it still exists, would exist in a state of homeostasis with its environment. It would have to in order to still remain existent. If terrestrial organisms were capable of replicating under martian conditions, they could easily eat everything up and then die off. Never quite getting the time necessary to adapt to the ecological limits of their new habitat. And by this process driving the native life to extinction as well.

To answer part 3: We're still discovering new kingdoms of life on Earth (though it's unlikely we'll discover new domains). If localized panspermia exists within our solar system (from meteor impacts or the like) it's possible martian life and terrestrial life are related enough for the martian life to fit within the already existing family tree of terrestrial life. https://astronomy.com/news/2021/05/did-life-on-earth-come-fr...

2. They'd never eat all of it. Also, it the distribution of either form will never be even across the planet. There will be "islands" of one or the other.

3. Biologists are easily able to determine if they are new kingdoms are not. They're also able to estimate how long ago divergence from a common root happened.

There are many, many examples of parallel evolution in terran biology, but none of them are confused with each other. It's absurdly unlikely that a terran modern amoeba will be confused with a Martian amoeba.

2) Localized sure, I wasn't arguing about the entire planet. But introduced life could drive the native life to a local extinction. And if it did so fast enough we would never know the local life had been there.

3) Yes, I know. While this isn't my specialty I work at an organization that does have people that specialize in this. The difficulty would be in definitively concluding whether this is a native divergence that we've just never seen before, or the result of Martian evolution.

2. We've found fossilized remnants of bacteria in rocks, haven't we? There's also ice on Mars. If life existed, we'd find it frozen in the ice.

3. A billion years of evolutionary divergence, with local alien adaptations, is going to be very hard to confuse with anything brought over by a probe.

I personally agree but was responding to the claim that finding fungal spores would mean we would necessarily turn mars into a nature reserve and not touch it. i pointed out the a fungal spore wouldn't be martin but earthly in origin

Declaring Mars a “nature reserve” would be completely unenforceable. Suppose you convince US Congress to pass a law banning Americans from sending humans to Mars, due to the risk of contamination to native Martian microbes. What happens when China says “now is our chance to show the world we’ve eclipsed the US by sending humans to Mars when they won’t“? Even though such a Chinese mission isn’t feasible today (an American one arguably isn’t either), who can say what its feasibility will be in another 20 or 50 years? And if not China, then sooner or later somebody else. Sustained global consensus on this issue is unlikely, which makes Mars as a “nature reserve” meaningless in the long-term. On Earth, the vast majority of nature reserves only exist because some government has military control of the territory and hence can enforce that status.

> Declaring Mars a “nature reserve” would be completely unenforceable.

Generally worked pretty well for Antarctica. A few research bases are permitted but colonization is internationally banned and not happening.

BTW, colonizing Antarctica would be a lot easier than colonizing Mars. Far fewer technical challenges to overcome, and much more practical experience overcoming those challenges.

Many people who call for Mars to be declared a "nature reserve" aren't just calling for a ban on Mars colonisation, they are calling on a ban on crewed exploration – either of the planet as a whole, or at least of sites they view as "environmentally sensitive" (which basically turns out to be the most interesting exploration targets, and many of the sites which would most easily host crews). They are worried about microbial contamination, which is a rather different environmental concern from Antarctica, and requires much stricter limits on human activity.

When someone like Elon Musk talks about "colonising" Mars, all he's realistically talking about – at first – is a crewed research station, so not that different from what we have in Antarctica. And many people who want Mars to be a "nature reserve" are opposed to even that. Yes, Musk hopes that such a research station will eventually grow into a buzzing metropolis, but I think if that ever happens it is a long way off. Musk might live to see crewed research stations established, I very much doubt he'll live to see genuine colonisation, much as he enjoys publicly fantasising about that topic.

Even the ban on colonising Antarctica only really works because it is banning something no government wants to do anyway. Crewed exploration of Mars would be attractive in principle to governments because of the benefits for national prestige, getting in the history-books, outshining the competition – the same basic reasons why the US went to the Moon. Of course, that benefit has to be weighed against the immense cost – but costs aren't constant, with further technological and economic developments it is going to become more affordable.

All the groundbreaking exploration opportunities with Antarctica have already been used up, so governments don't have the same motivations there. And I think the first human visit to another planet, is going to be much more noteworthy and prestigious and memorable, than whoever was first to explore some big freezing cold island on Earth. A thousand years from now, most people will still probably remember who Neil Armstrong was; I doubt many other people from the 20th century would still be household names (I suppose Einstein and Hitler would be the other likely candidates)–its only been a century or two, but the average person has no clue whom the first explorers of Antarctica were.

Right—living on Mars is like living on Earth if it ambient surface radiation levels were significantly higher, nothing would grow in the soil anywhere without a ton of preparation, and you couldn't leave your house without a pressure suit. And there's no surface water. And the gravity's fucked up. And the temperatures suck for basically anything life-related. And none of the geological and chemical processes that keep our biosphere viable existed, at all.

So... like Earth if several apocalypses happened at once, including a few nigh-impossible ones. Except it starts that way. And it's actually even worse than that. Sure, maybe we could slam some comets into it and do a ton of other sci-fi shit over a few centuries and it'd eventually get better, sorta, a little—but c'mon, seriously?

>how are we supposed to build a second home on a dead, ruthlessly hostile planet until we demonstrate ourselves capable of stabilizing the biosphere and building a sustainable long-term civilization here

because its unique challenges and constraints may make us develop technology that we wouldn't otherwise that may in turn out to be useful back on earth. Much of our technological advancements come from military research, where there was no civilian demand. We developed computers so we could break encryption, we developed the internet as a successor to arpanet a military network originally made to maintain command and control in event of nuclear exchange. standardized clothes sizing was invented to make uniforms more cheaply. satellites were invented so we could spy on our military rivals. the entire space program was a spin off of ICBM program. Nuclear power came from atomic bomb research, we have developed many advaced prosthetic due to injured veterans needing them. weather prodiction thanks to radar to detect enemy planes.

But what if we could have something less self destructive than war that would germinate new technologies? Thats what a reasons to colonizes space. space colonization gives us many of the same challenges war does without the need for mass loss of life. Needs for new materials, new means of generating power, new modes of transportation. space exploration will give us new frontiers to strive against rather than find better ways to murder each-other. the ease of earth doesn't provide those challenges. I can dig up my back yard throw seed on the ground and will have vegetables to eat in the fall but i have learned nothing, find a way to grow food from lunar or martian regolith and you just have invented a way to rapidly create new soil and solved earths soil erosion problems ans well as found new ways of removing toxins from contaminated environments.

>I can dig up my back yard throw seed on the ground and will have vegetables to eat in the fall but i have learned nothing, find a way to grow food from lunar or martian regolith and you just have invented a way to rapidly create new soil and solved earths soil erosion problems ans well as found new ways of removing toxins from contaminated environments.

We already have no till agriculture. The plants terraform the soil for us. The problem with this terraformation is that you need to rotate the plants because every plant terraforms the soil in a different way. Plants don't deplete the soil unless you replant the same plant over and over again and destroy terraforming progress through tillage and harvest it and then never bring the poop back.

Some people will now say that avoiding soil depletion in the short term is a bad idea because it means using a little bit more land (or bring up incorrect numbers).

Agreed 1000000% and this argument bugs the fuck out of me.

If we can't successfully terraform Earth how the fuck are we going to terraform Mars?

It goes both ways. Learning to live on a dead world like Mars (or better yet, off-world altogether) will necessarily entail significant improvements in recycling, atmospheric control, and energy management. Those same technologies could be critical to reversing the damage we've done to our homeworld and enabling us to live on it sustainably.

> sustainable long-term civilization here Earth is easy mode compared to Mars

Which is easier, building a colony on Mars or solving politics? I rest my case. Mars, here we come!

Do you imagine a Mars colony will not have its own politics? Politics is arguably motivated in large part by scarcity. On Mars resources are a lot harder to come by than on Earth.

You could make an argument that a shared struggle against extreme conditions would stabilize societies and make cooperation a necessity, but a Mars colony is going to need a lot of help from Earth to get on its feet, in which case we still need to solve terrestrial politics anyway.

> Do you imagine a Mars colony will not have its own politics

A Mars colony would be small by necessity. Everyone will know everyone else. In such communities "politics" is not nearly so abstract. For instance, you can't convince yourself that climate change is not happening when you personally know the experts in that field taking the measurements and crunching the data. There will always be disagreements but nowhere near the type of nonsense we see here on Earth.

Pretty much. I want to colonize Mars, but not as a solution to apocalypse scenarios. Long-long term it would help, but yea, it isn't the optimal solution to solve current problems we are facing now. Still want to colonize it, but just because it would be cool. Whether we take 5 years or 150 years to do it or 1,000 years to do it, doesn't bother me. Although doing it in the next 30 years would mean there is a good chance I could see it happen, but thats about it.

One big problem with Mars is that requires technology to live on. Most of the risks are civilization ending events not extinction level events. When civilization fails, on Earth the survivors bang rocks together, on Mars they die. It turns civilization ending into extinction.

One big question is if can make Mars civilization that would survive Earth collapse. It is possible that there are some things, like biological samples or advanced technology that have to come from mother planet. Mars will likely take a long time to become self-sufficient and until then it isn’t a backup. The easier self-sufficiency is, the less Mars is needed as backup.

The final thing is that colonizing Mars could introduce risks. It would involve developing technology that makes disaster more likely, like advanced AI, genetic engineering, or moving asteroids in space. Or could be adding a place for conflict leading to Earth-Mars war that destroys both planets.

> Most plausible post-apocalyptic Earths would be far easier to live on than Mars.

Most, but not all right? So then you agree that there is still a case for colonies on other worlds, if only to cover those less plausible scenarios.