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I think you’ll get downvoted but I largely agree with you about the futility of the exercise. The complexity of the Earth’s system for sustaining life still far

I think you’ll get downvoted but I largely agree with you about the futility of the exercise. The complexity of the Earth’s system for sustaining life still far exceeds our understanding, and I think going to Mars will at best turn out to be a powerful way to learn that we cannot replicate it. The typical moral justification is that the Earth may be threatened and so it would be prudent to have some humans somewhere else in the solar system. Well the number one threat to Earth is an impact event. If we can hypothesize a rapidly growing lift capacity, why not use that mass budget to develop a solar-system-wide system for detecting and if necessary altering the trajectory of potential impacting objects? It would be WAY better to protect the Earth than any other backup plan. The other big threat to the Earth would be a fast gamma ray burst but that would very likely get Mars and any other human colony as well. The reality is that people want to go to Mars for the same reason people want to go climb mountains: because it is there. Our economic system provides a very few people with the resources to pursue those dreams. Whether that takes away from everyone else depends on how you think about the economy—to what extent you believe it is zero-sum. Personally I think we should go to Mars for the simple purpose of going—I like exploration and climbing mountains too—but not fool ourselves about establishing a new human society there. To me it’s like say let’s establish a new human society on the summit of Everest. Which would be way easier than doing so on Mars, by the way!

DennisP 7y ago
In the absence of a thriving civilization in space, I don't have any confidence in governments to actually maintain adequate asteroid defense for the long term.
samatman 7y ago
> Well the number one threat to Earth is an impact event. If we can hypothesize a rapidly growing lift capacity, why not use that mass budget to develop a solar-system-wide system for detecting and if necessary altering the trajectory of potential impacting objects? It would be WAY better to protect the Earth than any other backup plan. Detection is a solved problem. Altering the trajectory of an asteroid requires a large amount of lifting capacity to be available on relatively short notice. That is, it has to already exist when the crisis is identified. Congratulations. You've identified a positive externality of Starship.
- disambiguously 7y ago
  Conversely, of course, the trajectory of a non-threatening near-Earth asteroid can be known well in advance, but there’s no obviously benign reason for anyone to bring a lot of delta-v to one. So having a steady traffic in commercial heavy lift could be a positive externality as well, for whoever wants to find a close-call asteroid that has been recently marked as 100% safe and give it a little nudge.
  - samatman 7y ago
    Making it easier for mustache-twirling supervillains to destroy Earth is not a concern of mine, personally. Weaponizing smallpox and distributing it in major airports is the lower bound of effort. Anything that exceeds this is not worth worrying about.
- snowwrestler 7y ago
  If you build such a capability on purpose you don’t have to hope you’ll be able to adapt a nebulous “positive externality” of some other system.
  - samatman 7y ago
    I don't think a purpose-built capability is anywhere near as good. It would be a massive drain on the economy that chose to maintain it, there's no guarantee it would actually work when the time came, and it wouldn't benefit from improvements in design over time. Being profitable, Starship has none of these limitations.
disambiguously 7y ago
> Well the number one threat to Earth is an impact event. Challenged— that’s the number one natural threat to (human civilization on) Earth. Or maybe the number one threat assuming we survive the next thousand years. The number one threat at this moment is deliberate annihilation of the ecosphere by a very small number of insane humans. The number two threat is negligent annihilation of the ecosphere by a plurality of merely shortsighted humans. Not only is a Mars colony uniquely susceptible to these existential risks, the process of building one could plausibly make them worse. Space folks like to talk a lot about how the technology you use to survive in space is technology you can use to live better on Earth. They don’t like to talk about how the technology you use to get to space is the same technology you use to murder human civilization anywhere it hides. I wonder why.

DennisP 7y ago

In the absence of a thriving civilization in space, I don't have any confidence in governments to actually maintain adequate asteroid defense for the long term.

samatman 7y ago

> Well the number one threat to Earth is an impact event. If we can hypothesize a rapidly growing lift capacity, why not use that mass budget to develop a solar-system-wide system for detecting and if necessary altering the trajectory of potential impacting objects? It would be WAY better to protect the Earth than any other backup plan. Detection is a solved problem. Altering the trajectory of an asteroid requires a large amount of lifting capacity to be available on relatively short notice. That is, it has to already exist when the crisis is identified. Congratulations. You've identified a positive externality of Starship.

disambiguously 7y ago
Conversely, of course, the trajectory of a non-threatening near-Earth asteroid can be known well in advance, but there’s no obviously benign reason for anyone to bring a lot of delta-v to one. So having a steady traffic in commercial heavy lift could be a positive externality as well, for whoever wants to find a close-call asteroid that has been recently marked as 100% safe and give it a little nudge.
- samatman 7y ago
  Making it easier for mustache-twirling supervillains to destroy Earth is not a concern of mine, personally. Weaponizing smallpox and distributing it in major airports is the lower bound of effort. Anything that exceeds this is not worth worrying about.
snowwrestler 7y ago
If you build such a capability on purpose you don’t have to hope you’ll be able to adapt a nebulous “positive externality” of some other system.
- samatman 7y ago
  I don't think a purpose-built capability is anywhere near as good. It would be a massive drain on the economy that chose to maintain it, there's no guarantee it would actually work when the time came, and it wouldn't benefit from improvements in design over time. Being profitable, Starship has none of these limitations.

disambiguously 7y ago

> Well the number one threat to Earth is an impact event. Challenged— that’s the number one natural threat to (human civilization on) Earth. Or maybe the number one threat assuming we survive the next thousand years. The number one threat at this moment is deliberate annihilation of the ecosphere by a very small number of insane humans. The number two threat is negligent annihilation of the ecosphere by a plurality of merely shortsighted humans. Not only is a Mars colony uniquely susceptible to these existential risks, the process of building one could plausibly make them worse. Space folks like to talk a lot about how the technology you use to survive in space is technology you can use to live better on Earth. They don’t like to talk about how the technology you use to get to space is the same technology you use to murder human civilization anywhere it hides. I wonder why.