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Comment by revscat | Hacker News Reader

You are getting downvoted, but I actually agree with you. Space travel is awesome, but so is living, and right now we are not living in a way that is sustainable over the short term. Space travel is, for me, an anachronistic hold-over from people who grew up with Heinlein, Asimov, etc., but is not something that is realistic given the environmental situation. Realistically, any vehicle that is dependent upon currently available propulsion systems is a waste of time.

Our resources would be better spent elsewhere. I know that this opinion is anathema on a tech-heavy site such as this one, but I must nevertheless express my respectful disagreement. It would be far, far more productive for the species to dedicate resources towards CO2 and CH4 reduction in the lower atmosphere.

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> Space travel is awesome, but so is living, and right now we are not living in a way that is sustainable over the short term.

Space travel is fundamental to the human species living sustainably in the long term. Correcting greenhouse gasses doesn't help us if the next day we find a planet-killer asteroid is a few weeks away.

While true, it is also not as direct of a threat. CO2 is affecting us now, whereas asteroids, etc., are (thankfully) only possibilities. Serious ones, to be certain, but not immediately threatening.

CO2 is a direct and immediate threat.

Humans as a species will survive CO2, though, whereas asteroids conceivably can go from "not immediately threatening" to "Earth will be destroyed in a few years" without warning.

"... few days"

I went with years there to be safe as I'm uncertain about what the detection levels are like for planet-killer sized asteroids. I know we discover house-sized ones passing between us and the Moon after they whiz by.

No detection. Who's looking? Many are found by amateurs, as you say, after they whiz by.

> not immediately threatening" to "Earth will be destroyed in a few years" without warning.

Unless the lead time is 50-100 years, years might as well be tomorrow, it's going to kill us all either way. Even that might be stretching it.

> Humans as a species will survive CO2

Maybe, personally I believe humans will cause their own extinction. I'm just not sure yet if we're going to take all life with us or not. Dealing with CO2 is a toss up between making the planet uninhabitable or completely inhospitable to life.

What study has indicated CO2 might make the planet completely inhospitable to life?

CO2 is a very real threat and we should be doing more about it. That said, the threat is neither direct nor immediate.

I don't think you fully appreciate just how difficult space travel is, especially the kind of space travel where you found a colony that will sustain itself after the Earth is hit by an asteroid. The required scale of technology/economy comfortably puts it in "at least several centuries from now, if we're incredibly lucky and/or devoted".

In this regard, the comment about CO2 is actually much more pertinent than it seems at first. If we manage to screw up the climate in this century (which seems very likely these days), inundating every coastal cities in the world, "sustainable space colony" will have to wait a bit longer. Much longer. If you're worried that an asteroid might hit us 500 years from now, you might want to rethink your priority.

Advancing chemical rockets now is important, but compared to the scale of space colony, it feels somewhat like producing better vacuum tubes to make sure (say) the US is the first to create strong AI. Any sane 50s US leader would have understood that "trying not to have a nuclear war with Soviet" is a much more important goal anyway: you can't fund AI research if your country is a radioactive wasteland.

> The required scale of technology/economy comfortably puts it in "at least several centuries from now, if we're incredibly lucky and/or devoted".

We went from not flying anything heavier than air to going to the Moon in 66 years. If we really really wanted to, we could go to Mars in thirty. This is a problem of priorities, not technologies (although the technological problems are real, they are not insurmountable).

any vehicle that is dependent upon currently available propulsion systems is a waste of time.

So... what, we just halt development of all vehicles, globally, period? Bye-bye trains, planes, cars, bicycles, and buses?

You can't develop the future of transportation or the future of propulsion systems if you literally shut down global commerce.

Besides, an airplane (for example) is not wedded to the engine. Developments in prop planes carried over directly to jet planes, once the jet engine matured. Any future propulsion system that can replace jet engines will probably not be hard to work into many plane designs of the day.

To be fair space flight has some significant advantages from an environmental perspective. Earth observation satellites are essential for understanding how the atmosphere works and how the planet is changing. Also, the unique constraints of space have lead to the development of sustainable technology such as solar panels, fuel cells, and better water purification.

Who cares? Let's feed the poor first and worry about bigger stuff later. Reminds me of a story about a letter written by Sister Mary Jucunda from Zambia to Dr. Ernst Stuhlinger, then-associate director of science at NASA's Marshall Space Flight Center. (http://www.meaus.com/whyExplore.html)

Well feeding the world is a more challenging problem than space flight ever will be. It is not like you can just sign a massive check and deploy some engineers and suddenly poor people in Africa will have enough to eat. But the comparatively trivial challenge of space flight can provide real benefits. Weather satellites can let farmers and governments plan ahead. A single remote sensing satellite can map desertification (which destroy farm land), and track floods (which destroy crops).

There are so many structural / societal problems in the way of feeding the poor that it's not a very interesting problem. You would have to re-engineer our society and power-structures.

Better to make incremental progress on poverty, without constraining the innovators to work on problems that don't interest them, or that seem even more intractable than e.g. space travel or AI.

Thanks. I expected the downvotes. But it breaks my heart that we have such a beautiful planet and we treat it like a trash heap, all the while dreaming of Mars and whatnot. Let's put our own house in order before we go off travelling.

There's no reason for everybody to stay home and do housekeeping, then there's a big beautiful universe out there. Dare to dream big!

If we can't even save our own home world, there is every reason to believe that we will do damage elsewhere. That being the case, best to stay home until we grow up a bit.

The rest of our solar system is rocks. Hard to do much damage there. Anything we do has to be for the better (oxygen, water, life).

Are you sure? I get the impression we're not very good at recognizing other life forms, or alternative forms of intelligence.

So we kill them. It wouldn't be the first time, and it won't be the last. This is life. Hopefully we'll learn something, except to be paralyzed by fear of doing damage.

I rather suspect fossil fuel usage, deforestation, etc. won't be an issue on Mars.

That's great; but Mars, and even the solar system, is not "the universe".

I suspect we're likely to solve greenhouse gas emissions long before we're able to get humans out of the solar system.

I suspect that in turn depends on whether we're able to create 'digital' humans or not.(I'm not weighing in on whether or not we'll be able to, just pointing out that if we can, 'manned' interstellar travel becomes much, much easier.)

The one easy option, voluntary restraint, isn't even on the table, not that I noticed. So what makes you think that's so likely, what about our current priorities and behaviours makes you so optimistic? Where is the economic incentive to solve the problem? Sure, it means more long-term life and profit, but having even 1% less quarterly profit so that in 1000 years some other company can exist at all is not exactly how we do things around here. Instead companies invested in fossil fuels are happily funding "global warming skeptics".

That proverbial man who plants trees knowing he will never sit in their shade is proverbial for a reason.. it's an amazing and heartwarming little saying because it's a contrast to how we generally behave, as individuals as well as organizations and masses. We learn from repeated catastrophe.. sometimes, maybe. But this problem is not one we can have a lot of attempts at solving. Right now we are still moving into the wrong direction, and probably even accelerating.. sure, hitting a wall can make people change their direction, but not if it breaks their neck, so to speak.

> So what makes you think that's so likely, what about our current priorities and behaviours makes you so optimistic?

I'm not enormously optimistic. I'm just saying that compared to interstellar travel, avoiding fossil fuels seems like a fairly small problem.

Earth doesn't need saving, it's perfectly fine. Regardless, in a world with practical interstellar travel local damage is irrelevant - the universe is infinite. Milky Way alone contains at least 100 billion planets.

What is damage? Life is change. Life modifies the environment. The Earth does seem to be the most interesting body in this region of space, but I don't view it as some sacred jewel that should be protected against all change.

You talk as if we can only do one thing, or as if there's any chance that we will all agree to pull in one direction or agree about what the most critical threats are.

SHORT STORY: A conversation between parent and child, on Mars, sometime in the future:

Parent: See that little blue dot in the night sky? That’s Earth.

Child: What is Earth?

Parent: Earth was the planet of our ancestors, before people came to Mars.

Child: Who lives on Earth now?

Parent: Nobody. It’s a dead planet. The actions of rich, selfish people destroyed it.

Child: How did the rich, selfish people destroy Earth?

Parent: They burned it up as fuel, getting to Mars.

That's why you build a Mars-dreaming company AND an electric vehicle company :)

"we" ? There's no we. There's just various groups of people. If one such group of < 10 000 people (spacex) can go off and build transportation to go to Mars, let them - no one should deny them to do that.

Those same < 10 000 people probably doesn't know nor have the ability to fix all the problems on Earth, but they might be able to get to Mars.

Fundamentally, we don't know where our resources would be best spent. We need to try all the things.

The biggest lever we've got right now is computation, so yeah maybe it would be more efficient to develop AI / IA first and then mass space travel, but we can't be sure.

Also, fundamentally we can accept a few billion deaths. That sounds and is grotesque, but it wouldn't be the end of humanity. I don't see how climate change kills us all in the next 100-500 years.

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