Seriously, is this a threat or is it the unexpected boon of getting a jump-start on terraforming? If you could press a button and "contaminate" Mars with life that would start spreading and generating an oxygen atmosphere, wouldn't you?
Yes I would; if you think it a useful idea for humans to become a multiplanetary species, then it seems to me just as important that life itself be multiplanetary.
And that we ought to be spamming as much life as we can, the hardiest Earth organisms, as far as we can onto any body where they stand a chance of taking hold - Venus, Europa, Martian poles, comets, lobbing things at distant stars with planets intending them to crash land. If humans can't make it off Earth, something might be able to, and it needs our help.
Well, the thing that sets living stuff apart from non-living seems to be the ability to sustain life (usually in the form of offspring). From this we can infer the purpose of life to be keeping life alive.
Spreading live across the universe being a good way to keep some of it going seems plausible. I'd obviously prefer intelligent beings like humans doing so, since so far evolution indicates this development path to have the best chances long term. But if not possible or too costly, spreading the next closest thing to us that is possible makes sense. At least as a form of backup. And sending microbes seem quite easy...
Well, that is obvious. Because causality works backwards and because we need conscious observers everywhere to make sure the laws of nature turn out just right for the universe to exist.
I didn't claim either of those things; if your counter-point is something better than "hurr durr humans are a cancer we deserve to die, we ruin everything" then I'd be interested to hear it. But if that is your counter, then I don't want to hear it.
But, the universe has been getting more complex all the time - every stage of its history over billions of years has moved towards more things, more complex interactions, more abstract organizations - fundamental forces splitting off, plasmas, galaxies and stars, fusion and heavy elements, solids and liquids and planetary systems, chemistry tectonics and weather systems and day/light cycles, LIFE, multi-celled life, biological systems and their interaction with weather, communication, socialization, organization, co-operation, industrialization, it just gets more abstract and more involved.
Unless you think a God exists and put a barren radiated rock somewhere for a good reason, then you may as well conclude that the universe is trying to get more complex. Like you can say that humans moved grass over the ocean for our own benefit, you can also interpret it that grass got humans to move it over the ocean for grass's long term survival benefit. There is only one known life-o-sphere and if one-day it is going to outside Earth, it needs a highly intelligent species to appear and move all the rest of it. That could be us, it could be why it looks like we're screwing up the planet - because long term, the point is not for us to stay here as bucolic agriculturalists, but to be an ignition chamber for something (probably silicon) to burst out and go forth.
What makes it our job is that nobody else can. Whales cannot do it. Cows cannot do it. Oak trees and crickets and fungus and cockroaches and E.coli aren't going to. Only humans can escape Earth intentionally, so humans have the obligation to do that on behalf of all life.
Compare how many humans think life is important (a lot), with how many humans think it important that Mercury stay barren until it gets swallowed by the Sun at the end of its fuel supply (the number of people who have even considered the idea in all human history, rounds to zero).
What makes it important? WE make it important, because - in the absense of a deity giving orders to us - who else can give meaning to anything, except humans? If nothing else, a more populated universe would be more interesting for us. Eventually.
It would mean you have a much harder time finding out if Mars once had life, if instead you're detecting mold that hitched a ride with your spacecraft.
I think you're right, this is the best argument against.
Kim Stanley Robinson's Mars Trilogy[0] deals with this a great deal, the early scientists pretty quickly devolve into two camps, terraformers and preservationists. There's a lot of other things going on as well, but this is one subplot.
At one point in the book, a terraformer made the argument if we discovered life on Mars we'd never know how or when it got there anyway. The monkeys in South America are an interesting parallel - total mystery. Best hunch is that some survivable population "rafted" across the Atlantic at some point - under conditions somehow rare enough to have happened exactly once in 40 million years.
KSR doesn't explicitly take a side, but seems to think that terraforming will be inevitable, so we might as well get on with it.
On the other hand, Mars may not be terraformable.[1] The challenges there are so extensive as to possibly be insurmountable. Consider that we are so accustomed to certain environmental conditions that changes so subtle as working extended hours in a popcorn factory can give us cancer.[2] Mars just has toxic soil, a low enough gravity as to probably prevent a sustainable atmosphere, and is constantly bombarded with radiation.
But who knows, futurism is hard because humanity is pretty ingenious.
Isaac Arthur has an extended video on terraforming that's worth watching if you want to dive deeply into this topic.[3]
I don't want to give any spoilers, but the weirdest part of Blue Mars (?) seems to take a side on the existence of life on Mars. Or am I misremembering.
if we discover life in mars, and is similar to other life on earth we definitely can estimate an evolutive point of fork among both. If the DNA is basically identical in mars and earth, is from earth. There is not a lot of time to accumulate a lot of mutations since 1971
That's fine though. Having a second home for humanity is more important than maximally preserving the ability to detect past life (note that we wouldn't be eliminating that ability, just hindering it somewhat).
Also, we think we'd be able to tell pretty easily whether any life detected is from Earth (i.e. we brought it along with us). Life that isn't descended from the same tree of life as us is likely to be radically different.
Mars will never be able to be a "second home" for humanity: it lacks the ability to maintain an atmosphere that can support humans due to its weak magnetic field.
The bottom of the ocean would be far more habitable if we faced any type of extinction event.
> The bottom of the ocean would be far more habitable if we faced any type of extinction event.
Yeah, space has a coolness factor, and there are things about the origin of the universe we can't learn from the bottom of the ocean, but an underwater station is one of the most underrated projects humanity could pursue.
Oceans are phenomenal shields against radiation, extreme weather, or even the temporary combustion of the atmosphere, should things get that bad. The opportunity to learn about groups surviving in isolated habitats, or about megastructures that have to survive hostile external environments, could even provide really useful lessons for space.
The lack of a magnetic field ablates away an atmosphere only on cosmic timescales, not human ones. That seems like a problem that could be solved with the benefit of thousands more years of technological development. Never say never. Just a hundred years ago many people argued it was impossible to ever leave the atmosphere of this planet (And it wasn't ... using cannon. The rocket solved that problem).
It's a moral hazard to hold out hope for a "home away from home". Terraforming Mars is a moonshot.
If we ever find ourselves in a situation where we cannot survive on a planet where food literally grows out of the ground, with abundant liquid water and atmospheric oxygen at 1 atm, how on Earth would we survive on a planet that is devoid of life, has no liquid water, an atmosphere that's 1% the pressure of Earth's with no atmospheric oxygen, and little to no sources of energy?
Again, the bottom of the ocean is far more habitable than Mars, even if we experienced a similar extinction event similar to the one we experienced 65 million years ago.
Earth is habitable now. There are plenty of plausible non-anthropogenic disasters that may make that so not so. Some typical examples include megavolcano eruption, coronal mass ejection, and asteroid impact. It would be good to not have all of our eggs in one basket here on Earth.
And it's for exactly the same reason of having redundancy that it would be a good thing for Earth to continue to remain habitable, i.e. we should stop ruining the planet through climate change.
It's not a moral hazard at all; the two outlooks are congruous.
> megavolcano eruption, coronal mass ejection, and asteroid impact.
Even after any of those events, the bottom of the ocean would still be more habitable than Mars.
> It's not a moral hazard at all; the two outlooks are congruous.
The moral hazard is that we'll begin to think of Mars as a backup, when it isn't one at all. The Earth is very likely to be the one shot we have at a home. If we can't manage to make Earth habitable in the face of catastrophe, there is little hope to make a cold, barren rock that's millions of miles away habitable.
What about impacts such as the one that created the moon? We can argue about likelihood of it happening again but large enough impacts can liquify even crust on the opposite side of the planet. The bottom of the ocean won’t help at that point right?
I mean, the likelihood is pretty important here. The likelihood of such a large impact was pretty high in the early solar system, and it was high for Mars, as well.
Yeah, but most of that was waiting around for oxygen-releasing life to evolve.
We could create an oxygen atmosphere on Mars much more quickly than that, because we'd be sending life explicitly for that purpose that's ready now, and we'd also be importing gases and digging up in-situ resources and turning them into gas.
> Yeah, but most of that was waiting around for oxygen-releasing life to evolve.
No, it wasn't. Photosynthesis that released O2 evolved relatively quickly, and was more efficient than other forms of photosynthesis. Then it took another billion years for oxygen to accumulate in the atmosphere. Mind you, we had an entire planet with oceans teeming with photosynthetic life. That will be next to impossible to replicate on Mars.
There are two oxygen sinks on Earth that reacted with oxygen released from photosynthesis: the first was the ocean, the other was minerals on land. This is the reason that it took so long for atmospheric oxygen to accumulate. Mars will have a lot of oxidizable minerals and compounds that will react with oxygen before it can accumulate in its atmosphere. Even then, it will escape into space without a sufficient magnetosphere to trap an atmosphere.
Assuming they originated independently, sure. Panspermia (see other comments) suggests that life from one planet might easily end up on another, or that both may originate elsewhere.
> If you could press a button and "contaminate" Mars with life that would start spreading and generating an oxygen atmosphere, wouldn't you?
No. Mars has a weak magnetic magnetic field which is incapable of containing an atmosphere that would support us. It also took Earth over 1 billion years for atmospheric oxygen to accumulate in significant amounts.
With active terraforming you could accumulate an atmosphere much more quickly than over the course of a billion years. We're currently adding a measurable amount of carbon dioxide to the Earth's atmosphere every year, which isn't great here, but would help tremendously to terraform Mars.
Probably not. We don’t know how that would affect other planets in our solar system. Besides you would need another button for “water”. Without it no multicell organism is capable of growing.
