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Earth has been hit by objects in the past, with devastating effects. Scientists largely agree that it was an asteroid or comet impact that started the chain of events that wiped out the dinosaurs around 60 million years ago.
[...] impacts from objects in space are just one of several ways that humanity and most of life on Earth could suddenly disappear.
We are already observing that extinctions are happening now at an unprecedented rate. In 2014 it was estimated that the extinction rate is now 1,000 times greater than before humans were on the Earth. The estimated number of extinctions ranges from 200 to 2,000 species per year.
From all of this very worrying data, it would not be a stretch to say that we are currently within a doomsday scenario. Of course, the “day” is longer than 24 hours but may be instead in the order of a century or two.
So what can we do about this potential prospect of impending doom?
[...] But the threats we face are so unpredictable that we need to have a backup plan. We need to plan for the time after our doomsday and think about how a post-apocalyptic Earth may recover and humanity will flourish again.
As computer experts, you are familiar with backup plans. What should we do to backup human survival ?
(Score: 2) by TheLink on Wednesday June 14 2017, @10:56AM (7 children)
I agree on most of the points except for 5). Bringing the mining stuff to the asteroids is probably better than moving the asteroids.
Generally mining involves going through tons of crap to get the few grams or kilos that you want. Go look up the actual ppms if you don't believe me. So it makes no sense to move the tons of crap you don't want.
The steps should be first to develop the artificial gravity and radiation shield technologies. Get them to a suitable level of maturity. Then work out how to mine stuff in space. Then actually mine stuff (preferably to be done by robots and other automation in most cases - unless the asteroid is one that's worth establishing a colony nearby - e.g. large high water asteroids like Ceres).
It is unscientific and silly to go to Mars before we've done experiments to figure out whether humans and our livestock can do OK long term on Mars G. It's not cheap to adjust the g on the surface of Mars. Much easier to fix it in orbit.
And all for what? The vast tracts of land on Mars are no real advantage since there's practically no atmosphere. You still have to cover every bit of land used for humans and livestock.
Due to Mars being a gravity well, getting goods from the _surface_ of Mars to/fro Earth (which is likely to remain the main economic centre for centuries) is going to cost a lot more than getting goods from an asteroid to/fro Earth (even if it's an asteroid in the asteroid belt).
(Score: 2) by kaszz on Wednesday June 14 2017, @12:51PM (4 children)
There is a case for sending people to the Moon and live underground for a year to establish the effects of low gravity on the human body. As a preparation for staying on Mars.
Mars has the advantage of a surface and most materials to sustain a colony.
(Score: 2) by TheLink on Wednesday June 14 2017, @04:54PM (3 children)
Asteroids have surfaces and materials too. There's no real huge gain with our current tech levels.
There's no scientific evidence that Mars gravity is good enough (or not). If it turns out Mars gravity is not good enough for humans, livestock etc in the long term then it's harder to fake suitable gravity on the surface of Mars (or the Moon) than it is in orbit.
Mars does not have much atmosphere. Even at the highest pressure areas water boils at 10C. https://en.wikipedia.org/wiki/Armstrong_limit [wikipedia.org]
https://science.nasa.gov/science-news/science-at-nasa/2000/ast29jun_1m [nasa.gov]
http://www1.lsbu.ac.uk/water/water_phase_diagram.html [lsbu.ac.uk]
So you'll have to cover those surfaces if you want to farm on them. No big difference from a space station. Might even be more expensive.
The gravity on Mars is enough to make it cost a lot more to get materials off the surface and back to Earth for trade etc.
(Score: 2) by kaszz on Wednesday June 14 2017, @06:41PM (2 children)
How do you get radiation protection in orbit from solar flares and GRB?
(Score: 0) by Anonymous Coward on Friday June 16 2017, @03:55PM (1 child)
In the similar way you'd get radiation protection traveling to Mars and on the Mars surface with near zero atmosphere and magnetic fields: https://www.nasa.gov/feature/goddard/real-martians-how-to-protect-astronauts-from-space-radiation-on-mars/ [nasa.gov]
Once you solve many of the problems of going to Mars and staying there, you don't need to go to Mars - it's a waste of time and resources. ;)
The only extra shielding on Mars is if you went underground or used the surface stuff to shield you. But one of the main advantages of the vast surface on Mars was to use it for livestock and plants right? So if you can't really use that, you might as well use a suitable asteroid.
And you can go underground in many asteroids too. Given the low gravity levels of some asteroids it might even be easier to fake gravity underground in them without making too many people suffer from motion sickness. It's also easier to ensure your human habitat is "floating behind" the asteroid (you may need to solve stuff like still getting solar energy while doing so).
(Score: 2) by kaszz on Saturday June 17 2017, @12:49PM
Indeed a interesting material.
Regarding Mars. I think there's a lot of things we have no clue about until we get there. So it will likely pay to go there in person to explore.
(Score: 2) by Grishnakh on Wednesday June 14 2017, @03:38PM (1 child)
I agree on most of the points except for 5). Bringing the mining stuff to the asteroids is probably better than moving the asteroids.
Generally mining involves going through tons of crap to get the few grams or kilos that you want. Go look up the actual ppms if you don't believe me. So it makes no sense to move the tons of crap you don't want.
The problem here is that many asteroids are in wacky solar orbits where they're only convenient for a short time, and the rest of the time they're just as inconveniently-located as Mars or worse. The idea with Earth-crossing asteroid mining is that you grab them when they're nearby and process them, and you grab ones that are smaller so you can feasibly control its location.
Later on, though, if you want to mine the Asteroid Belt, then you're right: it makes a lot more sense to just move the equipment to the asteroids. They're in stable orbits out there anyway, and they never come close to the Earth, so it makes more sense to mine them out there and then use fuel to move the processed ores to Earth.
The steps should be first to develop the artificial gravity
We already have that: it's called "rotation". That's the only way to generate "artificial gravity" right now. We haven't built anything big enough to actually try it out on though.
and radiation shield technologies
We have that too: it's called lead and water. Water is surprisingly good at protecting against certain types of radiation, for harder stuff you'll need dense stuff like lead.
With both these things, you need a sufficiently large station, and enough infrastructure in space, to make it feasible to mine all this stuff somewhere (asteroids, Moon) where there isn't a huge gravity well so you can build a station that uses them. Mining has to come first; it's too expensive lifting enormous quantities of mass into orbit (or worse, a Lagrangian spot); we have to get our resources in space. And we need an economic case to do all this in the first place. Just building space stations has no economic case unless a bunch of governments or billionaires are willing to fund it for kicks. Asteroid mining provides a real economic incentive to develop space-based technologies, for applications that are useful on Earth right now. Another article here talks about a shortage of Cobalt and how its price has doubled because it's in high demand for EVs; if there's cobalt-carrying asteroids in earth-crossing orbit, it may make economic sense to develop technologies to mine them.
(Score: 2) by TheLink on Wednesday June 14 2017, @04:44PM
We have the ideas and theories for generating artificial "gravity" in orbit/free-fall, but we don't have any mature tech for it. Even this was cancelled: https://en.wikipedia.org/wiki/Centrifuge_Accommodations_Module [wikipedia.org]
So we don't even have any _scientific_evidence_ that humans or our favorite livestock or even mice can do OK long term on Mars level gravity. Or Moon level.
Thus it is stupid and unscientific to even fund projects to put humans on Mars till such tests are done. If it turns out we need more than Mars G it's much easier to fake suitable "gravity" in orbit than on the surface of Mars. We do not have practical tech for doing a similar thing on Mars or Moon surface (maybe only those who can enjoy those spinning amusement park rides for hours can stay ;) ).
If we had no choice - no time to test, then sure, but that does not appear to be the case at the moment.
We do not need to build those expensive huge space stations to develop and test our technologies. Stations using tethers and counterweights can do the job for the early stages.
Don't forget getting stuff to and fro the Mars surface. From Low Mars orbit to Mars surface the delta-v is 4.1 alone. Mars surface escape velocity is 5km/s. That's not a small figure.