Because an extinction level gamma ray burst directed at Earth is an extremely unlikely event compared to many other possibilities, such as humanity trashing our own ecosystem, which is pretty close to a certainty at this point.
Also, outer space is really incredibly hostile to life. The likelihood of dying in space, on the Moon, on Mars, is vastly higher than the likelihood of the aforementioned GRB.
Let me put it this way: the Earth, in the aftermath of getting hit by the dinosaur-killing asteroid 66 million years ago, was still infinitely more habitable to life than Mars is today. The grass is not greener on the other side.
It would be so much easier to build underground or underwater shelters on Earth than it would be to build permanent shelters on other planets.
The Earth is the only habitable place in the solar system. Everywhere else requires humans to bring along their own life support systems, fresh water, and means to produce food. Human occupation of any body in the solar system or artificial bodies like a space station will always be limited by the amount of high tech infrastructure that can be built there. Even on Mars there's no guarantee there's enough in situ resources for humans to be self-sufficient.
So the only was an extinction event on Earth would be survived by off-world colonies is if they were 100% self sufficient. Even a broken toilet could kill everyone in a space vehicle, human lungs don't appreciate aerosolized shit in them.
Building a permanent off-world base is a huge undertaking. Building an actual colony is an order of magnitude more difficult. And building a completely self sufficient colony is several orders of magnitude more difficult than that.
In any sort of near term setting an extinction level event on Earth is going to lead to the extinction of all off-world colonies/bases. They stand even chances of completely dying out even with unlimited support from an intact Earth.
A solar flare could wipe out a space station or Mars base. A GRB capable of wiping out life on Earth will wipe out life pretty much everywhere in the solar system.
Life on earth, er outside the oceans would end with sterilization down to 1M. Likely 99.99% or more of humans dead within a year.
Mars however is very cold, highly radioactive, practically no atmosphere, and vulnerable to meteor strikes. So to fix all those problems inhabitants would likely be under 1 meter to minimize air leakage, radiation, heat leakage, etc. So it might well be that 99% of people survive a 1M deep sterilization ... only if self sufficient, which does seem a stretch, at least for the next century.
One example is infrared which we sense as warmth. I am somewhat fuzzy here, but I imagine that these photons bump into the atoms of our skin such that they tend to shake more vigourously than before. This is heat.
I can imagine that gamma rays of a gamma ray burst are plentiful and hard enough to influence the tardigrade matter to an extent to even kill tardigrades.
This said I see a way how tardigrades could survive a gamma ray burst. They are inside an asteroid or even inside a Mars-like planet. Even if the gamma rays ablate a significant chunk of the crust, enough will remain to protect the tardigrades.
So some tardigrades might be lucky to survive a gamma ray burst nearby.
So in order to survive the colonies would need to be entirely self sustaining, and would only save humanity from an event that wiped out earth but left the colonies unharmed.
Given the huge efforts that would be needed to create such colonies I think the work on spotting potentially dangerous asteroids and working out how to affect their orbits is probably a much better option.
A post apocalyptic earth after every nation on earth detonated all their nukes on each others population centers or a post dinosaur killer event would both leave the earth substantially more survivable than Mars at present. The world faces unlikely total destruction from space. More likely species extinction, and inevitable economic failure.
In the foreseeable future of the coming decades even inevitable economic failure is likely to doom any colony we establish whereas such colonies are not going to be enough to save the species from any species extinction scenario.
In the near term space exploration is about developing our potential not preserving it from destruction. Indeed this argument is both more palatable and potentially effective than doom and gloom.
From a philosophical point of view, what difference does it make if life on earth ends?
I am all for colonizing the galaxy, but just because I think it would be cool. It doesn't really matter whether or not it actually happens, does it? Why I personally think it is not widely a high priority is because establishing off-world colonies is just one of a really long list of things we could spend our time and money on, and most people themselves would not directly benefit.
I would prioritize it to some extent (maybe not highest priority) but I certainly understand why it is not a general priority.
> From a philosophical point of view, what difference does it make if life on earth ends?
Technically speaking, the end of life on Earth would be philosophically devastating, as all knowledge and subjective existence would vanish. Granted it may make no difference to you, but it would be catastrophic for philosophy.
Some very insightful and thought-provoking comments are under the above downvoted parent comment. I wonder what the Hacker News algorithm does with threads that have a downvoted parent but with highly upvoted replies? Does it push the thread down or keep it high? In either case, I've often thought that this was small flaw with threaded discussions (though I don't know a solution): There should be a way to maintain visibility or priority for great comments that are buried in downvoted threads.
There would be such a solution if users were able to adjust the weight of downvotes or if the vote mechanism was changed to include a mandatory category or reason, i.e. '-1 spam' or '-1 disagree' or '-1 flamebait'. This, in combination with a way to adjust the weight of those categories - i.e. I would give 'disagree' votes a weight of 0 since I don't care whether someone else agrees as I like to make up my own mind about things - would make it possible for those who like to downvote from the hip to continue doing so without ruining the discourse for others.
Such a system would quickly be gamed by the downvoters who would start marking things they disagree with as 'spam' so another layer would need to be added in which certain types of downvotes - spam, flamebait and other such categories - are checked and undone if needed. Downvoters who abuse their voting privilege too often would loose it for a day, then a week, then a month, etc.
In other words, something like the Slashdot moderation/meta-moderation system of old.
My read on downvotes is that they exist for managing signal/noise, basically for avoiding comments that are better off not read or engaged with. If a reader has to get through a noisy comment to get to a good comment that only exists because of the noise, is it worth it for the platform to try to lead them to it? And that's a pretty rare case anyway. So yeah, pretty hard to even specify a solution.
The general problem with up-votes, down-votes and no-votes is that the discourse mechanism behind them is so complex that the quality of the comment is only vaguely related to the number of votes. Sometimes I get lots of up-votes for a casual remark on a general topic, but none at all for a detailed reply on a specific question. When someone makes a false factual claim and is corrected by someone else, the last comment is often up-voted, but rarely is the original claim down-voted because people think the matter is settled.
Appart from obvious nonsense, the typical cases for down-votes are not descriptive (what is true or false), but normative comments (what should or should not be the case). Normative comments, such as what user `blueprint` has written, have the tendency that people up-vote or down-vote according to their own, often quite ad-hoc opinion, using the system like a poll. I think that this is not good. Instead, one should either just ignore it or try to initiate a debate. For the vast majority of opinions that contradict one's own, there are plenty of representatives out there who are at least as clever as oneself. Being curious about why they have such a view does not have to mean that one relativises everything. There is almost always something to learn.
I also think that we should strive to apply the principle of charity[1] in our responses, mending small flaws or bad rhetoric in a person's statements and instead challenge the essence of her or his thoughts. Although user `blueprint` does not elaborate on his topic, the topic itself is quite interesting. He just worded it a bit clumsily. Its essence may be reformulated as: "Given that an extremly devastating, but also extremly unlikely cosmic event could wipe out humanity in an instant, should we not prioritize to spread out across the galaxy, so that a single event could not affect all of us?" Has this statement the same chance to be down-voted? If this is not the case, doesn't it mean that a down-voter should have applied the principle of charity instead?
[1] Wikipedia's definition: "In philosophy and rhetoric, the principle of charity or charitable interpretation requires interpreting a speaker's statements in the most rational way possible and, in the case of any argument, considering its best, strongest possible interpretation." -- https://en.wikipedia.org/wiki/Principle_of_charity
