As the commentor below stated, I do not believe humans will colonize anything but our own solar system. Things are simply too far away, even assuming there is some breakthrough that speeds up travel by two or three orders of magnitude.

There have been several order-of-magnitude breakthroughs in travel speed for the past 200 years. We have several hundred million years of time on Earth to go, and a couple billion on the solar system, to figure it out. We also have plenty of time to figure out how to re-engineer and evolve our own bodies to deal with radiation and other hazards.

We will figure it out.

We simply exploited fossil fuels.

You are extremely optimistic about having several hundred million years left on Earth, when the longest living hominid existed for only ~2 million years.

I firmly believe that homo sapiens will self-destruct long before that point, as we have greatly overstressed the planet in only 200,000 years, mostly in the last 200.

This is a pretty terrible argument, mostly because it seems to support Musk’s and Zubrin’s position that if we stop progressing we risk falling into stagnation, decay, and ultimately extinction and yet you’re somehow using it to say we SHOULDN’T try expanding to other planets or star systems. It doesn’t seem logically consistent!

My view is that learning to master inhabitation of Mars and other places in space will enable us to revert Earth from a bunch of agricultural land and farms and suburban sprawl back into a garden (dotted with dense, luxurious cities) which we camp out in during the weekend.

Space development shows how to thrive WITHOUT fossil fuels. It’s so strange to me that folks seem to have this backwards.

I totally accept extinction. It's natural. Homo sapiens will burn bright and briefly, and the planets will continue to spin. I would argue that it would be much more worthwhile to spend money improving Earth for humans while we can, than dumping trillions of dollars into spaceflight (which I say unironically as someone who is currently paid by NASA).

>Space development shows how to thrive WITHOUT fossil fuels.

Not sure how that's the case given the staggering emissions of Falcon 9 for example.

From your comments I feel like you gotta be familiar with Kim Stanley Robinson's novel SF _Red Mars_ (if not you'd like it), but here's how he tries to make you feel better about your NASA budgetted job, while agreeing with your basic analysis on things like terraforming and many other things you've said (the plot of his earlier novel notwithstanding, he's partially doing penance for it).

> However, even if slower, terraforming Mars remains a great long-term goal; but long-term meaning like ten thousand years. Which means we have to get our relationship to our own planet in order for anything interesting to happen on Mars…

> The main project for civilization now is creating a sustainable way of life here on Earth. That’s the necessary first step; anything beyond would rely on that succeeding, so exploring space is less important now. That said, space science is an earth science. What we learn around the solar system can often illuminate the project we have here of keeping this planet’s biosphere healthy. So I like the space program, and feel it is not funded out of proportion to its importance. Robotic missions are already doing a lot of what we need done, but humans are better at many things than robots, and it’s more exciting to see humans on the other planets than it is to see robots. So, on balance, I’d like to see more investment in space science and less in areas like weaponry. Our taxpayer bailout of the banker gamblers who lost their bets in 2008 cost us about ten thousand times the entirety of what we’ve spent on NASA.

https://www.publicbooks.org/earth-first-then-mars-an-intervi...

This interview in particular is worth reading for this whole topic being discussed here.

I commented elsewhere about how much I like the series.

Every satellite in orbit that lasts more than a week or two uses solar or nuclear energy. Starlink is solar powered and uses electric rockets to reach final orbit and maintain position.

Hydrogen is one of the most common rocket fuels, and Starship will need to used synthesized methane (which we actually make on board ISS using direct cabin air carbon capture and the Sabatier process using hydrogen made from water split with solar electricity) on Mars to return to be reused, and Musk said SpaceX would eventually use synthesized methane for Earth-side refueling of Starship as well.

Human extinction is likely linked to extinction of all higher order life forms on earth.

The 6th extinction is well underway IMO

> My view is that learning to master inhabitation of Mars and other places in space will enable us to revert Earth from a bunch of agricultural land and farms and suburban sprawl back into a garden (dotted with dense, luxurious cities) which we camp out in during the weekend.

How does that work, exactly?

In space, any food produced would have to be grown inside, sealed away from the outside environment to protect it from the vacuum or near-vacuum of space or Mars. We will grow it in greenhouses or perhaps vats (staples like corn or wheat can be replaced by fermented foods like @solar_foods or @feedkind, using ultimately solar power, this is actually more efficient than photosynthesis and with a much smaller environmental footprint than agriculture) and certainly not have free grazing cattle (which is the biggest land use in the US). On Mars, we’re already beginning to master solar/battery-electric flight, so perhaps we may not need so many surface roads and we can place trains and such underground. Our footprint on the planet Earth could shrink by an order of magnitude even as our economy and quality of life improve (the density effect on economic productivity is well-established—and Mars will be really expensive to live on unless in large, dense cities... suburban sprawl being prohibitively expensive). These are all things that are fairly hard to prove on Earth as the whole system has an inertia due to developing with abundant fossil fuels, but on Mars we will be forced to rely entirely on renewable (mostly solar but perhaps wind and geothermal) or nuclear power, so a Martian society becomes a blueprint and a powerful proof of concept of how Earth life can be..

We use the rare Martian mineral handwavium

>We simply exploited fossil fuels.

This hand waves away all the accomplishments in seafaring prior to the 19th century.

What were the order of magnitude speed developments in seafaring before 1800? I'm not familiar with the topic.

Navigation techniques improved substantially. While not inherently a speed improvement it increased the effective range of mariners by a ton resulting in effectively the same thing.

> While not inherently a speed improvement it increased the effective range of mariners by a ton resulting in effectively the same thing.

There were loads of innovations around the shape and profiling of ship hulls depending on conditions in which they operated. Same for sails and stuff, not to mention doing away with rowers. This improved speed quite a lot on top of range.

Thanks, that's more insightful!

Navigation is irrelevant to the space flight argument though, we know how to navigate between planets and stars (in theory). Speed is the limiting factor.

> We simply exploited fossil fuels.

Not simply, but mostly: progress started before the steam engine. But yeah, pop sci is hyping a lot of things that are very, very unlikely in the near future, and it looks like we won’t have much beyond that.

If you firmly believe that homo sapiens will self-destruct in such a time, then why would there be any value in preserving Mars?

If I may: homo sapiens has self-destructive tendencies, which we acknowledge and for which we sorrow. But we love them anyway, and wish to see their continued survival, if it happens. We accept that populating another planet does not fix our psychosocial problems, but it may help us get through the great filter.

We could learn how to "simply exploit" atomic fuels. That should be good for another magnitude or two, right?

The funny thing is that we know already quite a bit about how to exploit them. Now, putting that into practice is another matter.

Which parts of our solar system do you think we should colonize?

None besides Earth.

It seems that you're implying that humans shouldn't interfere with any celestial bodies because of the inherent value of their pristine existence.

There's so many engineering and scientific advancements needed to make space-based sustainable colonies using materials sourced solely from Earth that your position would delay any colonization of space past a few great filters.

I was enjoying your takes on preserving Mars, but saying that humanity should only be allowed to change Earth is nihilistic in the extreme.

Not even a cozy hotel on the moon, overlooking the earth?

I'd be down, but it's more likely going to be an awful penal mining colony armed with nukes pointed back down at us.

The moon is a useless place to locate military weaponry for use against earth.

It would take those nukes three days to reach earth, which is a huge amount of time for countermeasures to target and destroy them. And a handful of responding nukes could easily wipe out all lunar military sites and personnel, while lunar weapons could barely nick Earths military capabilities.

Why?

Why should we spend trillions of dollars to put a few people on a distant rock when we could spend that money to help many more people right now, and potentially avert the need for a colonial life raft? It feels self-evident to me.

> Why not? It would seem that's something we're going to have to master in order to populate the galaxy.

I think the unstated premise here is that populating the galaxy is something we should do. Looking around at what we're doing here on Earth, I think humanity populating the galaxy would be a net negative for the galaxy.

You know how the aliens from Independence Day are portrayed as a race that goes from planet to planet draining its resources until there's a husk left? That's exactly what humanity would do. There's no question about that.

https://independenceday.fandom.com/wiki/Harvesters

"The Harvesters are a race of highly intelligent and incredibly technologically advanced hive-mind extraterrestrial beings. They are a threat of universal proportions that seeks to harvest and destroy planets to refuel their ships, to grow, and to perfect their technology at the expense of driving indigenous races to extinction."

We are the Harvesters in this story.

We aren't going to populate the galaxy. We aren't even going to populate Mars. We are going to live on Earth until something cataclysmic happens, and then we will be gone.

I strongly disagree with this. We have several hundred million years left, and we've only been around as an intelligent civilization for what, 100K years?

200 years ago nobody would even think of flying on Earth, and yet here we are, taking it for granted that you can get almost anywhere on this planet within 24 hours for a couple thousand dollars, and within a century of inventing the car we landed a robot on freaking Mars.

Now I do think that we will take charge of evolution and invent a form of life that will be our successor to withstand a much harsher range of conditions and absent from the "bugs" of current life such as cancer and heart disease, rather than our current unreliable meat bags, but we'll make it happen nonetheless.

All that said -- I do want to see more attention toward terraforming Earth as well. Even with zero global warming, the sun's brightness will increase such that our oceans will boil away within 1 billion years, even though it won't actually engulf the Earth for another 4 billion. I would think it's realistic to extend the habitable period of life on Earth from ~300 million years to maybe 2 billion years with some terraforming tricks. That will buy us more time to terraform Mars or Saturn's moons in preparation for the red giant phase of the sun.

Also, learning to terraform the Earth can reverse global warming, because, you know, politicians don't give a fuck about stopping it, so we should attempt to learn to reverse it as a backup plan while the political environmental efforts continue in parallel.

I think the disconnect here is between potential and probable. Humanity likely has the potential for interstellar travel, but our nature will prevent it in my opinion. Homo sapiens have twice come to the edge of nuclear oblivion already (being saved only by luck essentially), and I would wager we are are speeding much faster towards nuking each other than reaching the stars.

If nuclear war breaks out, it will be sad, we will lose a lot of our population, and cities will be destroyed, but I do not think a nuclear breakout will result in the death of humanity. I cannot see a realistic war scenario in which we will destroy every habitable corner of the planet.

And if we can cure cancer in the next 50 years (I think realistic), we'll have even better odds of surviving an event, as a species.

The collapse of all plant life would mean the death of humans. Nuclear winter is a well-studied and modeled phenomenon.

I don't think we would collapse all plant life.

While we have the theoretical capability to destroy all plant life, I think realistically we'd end up obliterating a few cities before war would cease, and a full-on nuclear winter is unlikely.

> I don't think we would collapse all plant life.

I mean it's not really about what you think. See the top two links here about the devastating effects of small-scale conflicts

- https://doi.org/10.1038/d41586-020-00794-y

- https://doi.org/10.1073/pnas.1919049117

- https://doi.org/10.1126/science.222.4630.1283

- https://doi.org/10.1029/2019JD030509

- https://doi.org/10.1080/03036758.1986.10423349

- https://doi.org/10.1029/2006JD008235

You don’t need to kill all plants, just enough of those we can eat. Not even all of those, either. Look into history to see what happens when enough people don’t have enough to eat.

The person you are replying to has said he would not mind if all humanity were to die and go extinct. Ugh.

Why should I mind? Species come and go.

Then you shouldn’t mind people making use of Mars in the meantime. Planets come and go as well.

> We have several hundred million years left, and we've only been around as an intelligent civilization for what, 100K years?

This sounds wildly optimistic, considering our chronic inability to fix our behaviour before it results in excessive damage. Never mind the occasional asteroid.

> 200 years ago nobody would even think of flying on Earth, and yet here we are, taking it for granted that you can get almost anywhere on this planet within 24 hours for a couple thousand dollars, and within a century of inventing the car we landed a robot on freaking Mars.

The myth of Icarus is a bit older than 200 years. So are Leonardo da Vinci’s drawings. Plenty of people did in fact think of flying, most probably before they had any way of writing it down for us to read.

It's been 241 years since the first manned unpowered flight, in a hot air balloon. Granted that's a long way from getting anywhere on the planet, but I'm skeptical that 41 years after that event no one was thinking of flying.

Not with that attitude.

That's really likely to be true if you walk into the future believing it.

Seems a little grandiose considering its just a comment on HN.

Better to master our behaviour on our own planet first before we go and trash another.