In this setting humans have settled all around the solar system but the bulk of the population is still in earth however an asteroid wiped out all life. Now can humans sustain themselves with whatever resources are available in space and planets

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    $\begingroup$ How established is their presence off-world? $\endgroup$
    Aug 18, 2021 at 5:56
  • $\begingroup$ They have factories,farms and mining operations going around everywhere however theres not many of them but I guess enought to sustain a healthy population. They are almost all around all planets that has something valuable to extract $\endgroup$
    – Guest253
    Aug 18, 2021 at 6:00
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    $\begingroup$ You're going to need to be more specific than "everywhere". $\endgroup$
    Aug 18, 2021 at 6:01
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    $\begingroup$ How advanced are these facilities? Are they just tin cans/research outposts, or do they have spaceflight capabilities? How advanced is space travel technology in your setting? We need to know a lot more to know whether they'll be able to survive or thrive or just starve to to death. $\endgroup$
    Aug 18, 2021 at 6:12
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    $\begingroup$ There are ways to survive even with ease, so as there are ways to fail in that aspect - depends on starting conditions. If you do not have figured out the starting conditions, then probably a better question would be - what are the main things they have to have to survive in such situation. Edit you question to make it more meaningfulll/answerable and if you do not have additiinal information on starting conditions then change what you ask. $\endgroup$
    – MolbOrg
    Aug 18, 2021 at 6:55

2 Answers 2


Your aims are basically mutually incompatible.

If humans have developed the technology and invested the capital needed to let them populate most, if not all of the solar system, even at a relatively low level (compared to Earth) then by default they are more than capable of preventing an asteroid from obliterating life on Earth.

This is because, even if they are limited to the inner system (i.e. the asteroid belt, Mars, the Earth/Lunar gravity well and Venus etc) they must have the technology (think astronomy equipment, rocket drives and manufacturing capacity etc) to intercept any normal orbital body, like an asteroid entering that space before it hits the Earth .

And if they don't? That means they must have deliberately chosen not to. Which means in turn that you then have to come up with some plausible explanation in your plot line for why they didn't intervene when they could have.

And here's the rub - if they choose not to it can only be because they are no longer reliant on the Earth to provide any of the goods or services (think food, medicine, tech or expertise etc) needed to keep the space colonies running. If that's not the case? If they are still dependent on supplies in some form or another from Earth? Then failing to intervene means they commit suicide!

And this holds true BTW even in a scenario where they hate 'Terra' and are effectively at war with all or some of the nations of Earth. They could only afford to deliberately target the Earth for destruction by dropping a rock on it if they were no longer reliant on it to begin with.

In short given your starting conditions there has to be either lots of places in the solar system where they could extract, water/oxygen and minerals and everything else they need survival (which means they are more than capable of stopping a rogue asteroid etc if they want to) or there exists lots of capacity to lift what they can't get for themselves off the surface of the Earth into space. In which case Earth itself could launch an interception mission even if the 'colonies' weren't interested. Either way by default someone has the capacity to stop Earth being destroyed in the first place unless it was an act of war.

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    $\begingroup$ I'm not sure that the ability to colonize planets necessarily means you have the ability to deflect any and all asteroids. I think it'd still be possible to have a high-speed asteroid coming from behind some other body that wouldn't be noticed until it's too late. If this society hasn't taken the existential threat of asteroid-caused extinction seriously and prepared a warning and deflection system in advance, it may be too late to save earth. That colony ships have been launched at some point in the past doesn't imply they have asteroid killers just lying around ready to launch. $\endgroup$ Aug 18, 2021 at 13:03
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    $\begingroup$ Asteroids large enough to wipe out all life on a planet would be spotted and tracked years prior to the actual expected collision. These rocks don't suddenly change their orbits, and they're large enough to sometimes be spotted by very primitive telescopes. Now, if one changed its course unexpectedly... But it takes a lot of energy to do. Or it could be an extrasolar relativistic kill vehicle, but "genocidal attack by aliens" is probably not the story you want to write... $\endgroup$ Aug 18, 2021 at 15:00
  • $\begingroup$ I was going to say much the same thing myself tomorrow. Basically the velocity differences (relative to Earth) between extra solar asteroids/comets and conventional solar planetesimals isn't enough to make a real difference. The object hitting Earth has to be (A) very large or (B) very fast to cause an extinction level event. Large ones of either type would be detected well in advance by the society described in the question. And if they are small objects neither class naturally travels fast enough to do the damage required . So basically someone has to take a pot shot at us. $\endgroup$
    – Mon
    Aug 18, 2021 at 15:27
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    $\begingroup$ I don't think this answer takes seriously just how freaking big an extinction level asteroid or comet is or how big space is. Some estimates place the size of the Chicxulub impactor at as much as 80km in diameter. At that scale, even a tzar bomb might not do any more than break it up into many smaller life ending rocks. Also, if the impactor is a comet, we may not see it very far in advance despite this size. Things that size are REALLY hard to detect in the Orrt cloud; so, while it is possible we would notice something that size coming far in advance, it is also very possible we would not $\endgroup$
    – Nosajimiki
    Aug 18, 2021 at 15:51
  • $\begingroup$ Or, it could be a space mining thing gone wrong. Maybe your colonists tried to fling a large asteroid into orbit to be mined so every one knows it is coming, but at the last minute a maneuvering jet explodes sending the asteroid on a collision course instead of a low orbit. $\endgroup$
    – Nosajimiki
    Aug 18, 2021 at 15:53

It's going to be hard to impossible.

When settling in a new environment, survival is strongly dependent on having supplies from the motherland until the time a sufficiently stable local supply chain has been established, meaning growing food, having water and gathering materials.

Without those elements the local community is very fragile and can succumb to the first harshness.

For a reference, look at European colonies established in the newly discovered continents: until they had established farming, safety and manufacturing, a single harsh winter was enough to wipe them out.

Even if they have a somehow established local food chain, they would still depend on anything that cannot be manufactured locally: if that's critical for survival, they have no hope if they can't produce it in loco.


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