Could humanity survive an asteroid strike?

[Simon_Jester]

An asteroid strike wouldn't necessarily stop the water cycle, though it would no doubt disrupt it. Global temperatures drop off dramatically but that doesn't mean it stops raining.

[jwl]

What's all this about nuclear power stations, anyway? Just stock up fossil fuels, are you worried about global warming or something?

[Purple]

What's all this about nuclear power stations, anyway? Just stock up fossil fuels, are you worried about global warming or something?

An atomic reactor is smaller, more reliable and does not require wasting valuable space on storing fuel.

[Simon_Jester]

For a purely underground installation that's a fair point. For a surface installation it might actually make more sense to go with fossil power- because we can build more of the coal-fired or gas-fired or whatever facilities, build them cheaply and quickly, and thus have more desperately needed electricity during the dark years.

[jwl]

What's all this about nuclear power stations, anyway? Just stock up fossil fuels, are you worried about global warming or something?

An atomic reactor is smaller, more reliable and does not require wasting valuable space on storing fuel.

Smaller I get. More reliable? A nuclear reactor power station and thermal power station are exactly the same except one has a furnace and the other has a nuclear reactor. I really don't see how a furnace can substantially wrong.

[Purple]

Smaller I get. More reliable? A nuclear reactor power station and thermal power station are exactly the same except one has a furnace and the other has a nuclear reactor. I really don't see how a furnace can substantially wrong.

Well for a start the mechanism needs constant tending to feed it fuel. And this feeding system along with the fuel storage system incur extra complexity and can fail. An atomic reactor is pretty much a plug in and leave sort of affair. Also, I would be hesitant to bury any combustion based generator underground should for what ever reason the ventilation fail.

[Sea Skimmer]

Some humans would certainly survive such an impact, but I would expect it to be very low.

In terms of designing facilities to allow such survival easily, that really depends on how close you expect to be to the act impact.

Within a certain radius you'd be outright buried alive by debris fall and require a large scale capability to dig yourself back out. Combustion based power is not even remotely an option because your air intakes would clog. Nuclear resistance facilities normally had diesel generators, but you were not expecting to use them for 72 hours after a high yield nuke war. But this rock would be burying stuff under 30 feet of rock and dirt at a range of a thousand miles, or something like that. You would need nuclear effects like protection from air blast at a pretty wide radius too. That can work with air intakes, it does work, but the blast valve and expansion chamber systems tend to be long and big. Turbocharged diesels don't really mind that, other forms of combustion based power will to varying degrees.

Depending on the exact range relying on battery power can be an option, as the nuke bunkers expect to do for the first 72 hours. You'll need around 6 months of power for filtered air overall for the people inside, as that's about how long we think the Dino killer dust cloud would have lasted. In reality that's a fairly crude estimate, but fine enough for planning purposes.

Also I'd point out since this is not a nuke war, if you are in a location far from the impact you could have a hydro power dam on the surface, and use the reservoir for protected power. It would get partly filled with debris but it should certainly be able to remain operational. The only risk would be human damage to it before the dust cloud actually appears to quickly kill anyone without good shelter, and force the rest indoors for months.

At that point you would have a lot of stuff to loot, though human bodies would still be decaying everywhere too.

Nuclear power is pretty ideal, but it'd have to be very small reactors, and you'd have no chance of refueling or repairing them realistically, so they'd only be good for at best a few decades. The cost gets high fast considering you may only need it for a limited period, and giant underground fuel tanks are an option, 500,000 ton salt cavern kind of tanks. I'm not sure how oil tankers on the ocean surface would fair in this though.

[Simon_Jester]

Well for a start the mechanism needs constant tending to feed it fuel. And this feeding system along with the fuel storage system incur extra complexity and can fail. An atomic reactor is pretty much a plug in and leave sort of affair. Also, I would be hesitant to bury any combustion based generator underground should for what ever reason the ventilation fail.

Nuclear reactors need constant attention by technicians to make sure they continue running smoothly. I mean, you could maybe set the controls to 'simmer' and walk away for eight hours, but you could do that with a variety of combustion engines too.

Some humans would certainly survive such an impact, but I would expect it to be very low.

In terms of designing facilities to allow such survival easily, that really depends on how close you expect to be to the act impact.

Within a certain radius you'd be outright buried alive by debris fall and require a large scale capability to dig yourself back out... burying stuff under 30 feet of rock and dirt at a range of a thousand miles, or something like that.

Shit, you're right, I hadn't thought of that. On the other hand, if you were trying to protect the planet, you may well go "we're planning on the assumption that the asteroid will hopefully hit the other side of the planet, because if it lands on the same continent as us we're fucked anyway."

Or you might even have multiple 'grades' of shelters and protection, the high-end but expensive ones designed to survive a near miss (i.e. to dig out from under thirty feet of shattered asteroid-gravel) and the low-end ones designed to survive only as long as the hit is on the other side of the planet.

Also I'd point out since this is not a nuke war, if you are in a location far from the impact you could have a hydro power dam on the surface, and use the reservoir for protected power. It would get partly filled with debris but it should certainly be able to remain operational. The only risk would be human damage to it before the dust cloud actually appears to quickly kill anyone without good shelter, and force the rest indoors for months.

Is the dust cloud killing anyone who lacks a filter mask? I wouldn't be surprised if it did but I don't know.

Nuclear power is pretty ideal, but it'd have to be very small reactors, and you'd have no chance of refueling or repairing them realistically, so they'd only be good for at best a few decades. The cost gets high fast considering you may only need it for a limited period, and giant underground fuel tanks are an option, 500,000 ton salt cavern kind of tanks. I'm not sure how oil tankers on the ocean surface would fair in this though.

If hit by a rain of ballistic rocks, poorly; if not hit by rocks, well I imagine.

[Guardsman Bass]

Shit, you're right, I hadn't thought of that. On the other hand, if you were trying to protect the planet, you may well go "we're planning on the assumption that the asteroid will hopefully hit the other side of the planet, because if it lands on the same continent as us we're fucked anyway."

That's what I'm thinking too. We're probably not going to be able to figure out where it will land until it's very close, at which point we can't do massive shifts of population and preparation anyways. You might as well just figure that it's statistically likely to land in one of the oceans and plan accordingly. If it lands in the middle of Kansas and kills everyone in North America, well, you did your best.

What's the best place (for humanity) that it could hit? I suggested the middle of east Antarctica in one of my earlier posts, but I'm not so sure on that now. Central-North Greenland would be uncomfortably close to Europe and North America, but it would also direct most of the energy into a two-mile ice sheet, and the ice sheet is surrounded by mountains.

Nuclear reactors need constant attention by technicians to make sure they continue running smoothly. I mean, you could maybe set the controls to 'simmer' and walk away for eight hours, but you could do that with a variety of combustion engines too.

Maybe not smaller ones. NASA was developing a nuclear reactor for their Icy Moons Orbiter proposal that would have been in operation for years without anything but remote assistance.

[Sea Skimmer]

Is the dust cloud killing anyone who lacks a filter mask? I wouldn't be surprised if it did but I don't know.

It would certainly kill anyone over most of the earths surface. If you had a facemask it would just clog up in short order, a bunker facility would be built with intakes that remove debris in several stages without only using a filter.

Block out the sun isn't a joke with an impact like the K-T event. Even after the initial clouds settle the shear amount of fine dust will remain dustbowl like super storms will be a regular thing for years to come, until either the rain eroded most of it or plant life established. Some areas will do better then others. Areas under thick debris will just be dead for centuries.

If hit by a rain of ballistic rocks, poorly; if not hit by rocks, well I imagine.

I'd expect rock death anywhere within thousands of miles, my concern is just how badly the megatusnami sweeping the world ocean basins will be. Close to the impact the solid earth/water splash will be thousands of feet TALL inflicting coastline transforming damage as it sweeps out past the actual crater rim. I reckon that might still be a problem really far away..... and if all shore facilities are wiped out or silted up using ships as a dispersed, survivable source of supply isn't going to work well.

Submarine supply vessels, if you want expensive, would have a certain immunity to the wave issue.

Maybe not smaller ones. NASA was developing a nuclear reactor for their Icy Moons Orbiter proposal that would have been in operation for years without anything but remote assistance.

Very low power though, and very considerable power is needed just for air systems and cooling any heavy sealed building or bunker, at least if you want to save people by the thousands. Claims have been made for sealed unit nuclear reactors that would do 30-40MW kind of powers, but none has actually be demonstrated in service. Keeping the size down means they could in principle be delivered complete, and built in a factor, while normal land power and naval reactors are assemble on site/ship. I'm more then a little skeptical of the whole idea working out well, and it would still cost a lot of money.

If you wanted really big shelters, hundreds of thousands of people, large underground reactors with refueling gear are plausible, Russia really did put three under a mountain ridge that made Pu-239 and hundreds of megawatts of electrical power and heat. China was building a similar facility but never completed it due to the end of the cold war.

However one big problem with operating after a major asteroid impact is loss of cooling water. The climate is going to change badly. The Russian plant I mentioned still used a normal style of river water cooling intake. The river could literally dry up and leave you with no power, even be diverted by damage or enormous mudslides, secondary earthquakes.

The way around that if you can't ensure water is an underground heat sink, just a huge number of geothermal wells and some bunkers work like that when sealed up, but an enormous number would be needed for a large nuclear reactor. Straight air cooling with minimal water loss is an option if you only operated the nuclear plant after the impact, and planned to dig out the air intakes.

[Sea Skimmer]

http://imageshack.com/a/img922/6415/bCKouK.png
wide image warning, not sure what our standard on that is anymore

This would be an example if what your going to have to do with all your incoming air for a while, since even for combustion you'll need to clean it to avoid fouling boilers or cylinders. This is not an example of a really high hardness air system though, so don't think it excessive.

The blast valve and chamber will still be needed anywhere close to the impact. Though on the plus side you don't have to worry about the dust itself being a radioactive hazard, so if anything does clog clearing the repair, after closing the intake, isn't the same problem. Filters could be cleaned and reused, and the dust entrapment chambers shoveled out.

[jwl]

Some humans would certainly survive such an impact, but I would expect it to be very low.

In terms of designing facilities to allow such survival easily, that really depends on how close you expect to be to the act impact.

Within a certain radius you'd be outright buried alive by debris fall and require a large scale capability to dig yourself back out... burying stuff under 30 feet of rock and dirt at a range of a thousand miles, or something like that.

Shit, you're right, I hadn't thought of that. On the other hand, if you were trying to protect the planet, you may well go "we're planning on the assumption that the asteroid will hopefully hit the other side of the planet, because if it lands on the same continent as us we're fucked anyway."

Or you might even have multiple 'grades' of shelters and protection, the high-end but expensive ones designed to survive a near miss (i.e. to dig out from under thirty feet of shattered asteroid-gravel) and the low-end ones designed to survive only as long as the hit is on the other side of the planet.

That's quite easy to protect against. Make two facilities, each on either side of the planet. But this is presuming you wouldn't know which side of the planet the asteroid is going to hit. It is known the asteroid will hit, which side of the planet the asteroid will hit will probably be also known.

[Zwinmar]

All of this is assuming that such a strike wouldn't trigger seismic activity, which I think it probably would, perhaps even setting off Yellowstone.

[Simon_Jester]

Shit, you're right, I hadn't thought of that. On the other hand, if you were trying to protect the planet, you may well go "we're planning on the assumption that the asteroid will hopefully hit the other side of the planet, because if it lands on the same continent as us we're fucked anyway."

Or you might even have multiple 'grades' of shelters and protection, the high-end but expensive ones designed to survive a near miss (i.e. to dig out from under thirty feet of shattered asteroid-gravel) and the low-end ones designed to survive only as long as the hit is on the other side of the planet.

That's quite easy to protect against. Make two facilities, each on either side of the planet. But this is presuming you wouldn't know which side of the planet the asteroid is going to hit. It is known the asteroid will hit, which side of the planet the asteroid will hit will probably be also known.

Making such facilities in multiple locations on every continent would be a good idea.

And to be fair, we would probably know impact location to within twelve hours- assuming this thing was detected many months or years away; a few years would be minimum time to build shelters capable of usefully withstanding the strike. But we might have trouble predicting whether the asteroid would strike, say, Europe or North America, or which end of the Eurasian landmass it would hit. In addition, it is almost inevitable that we would be launching multiple deflection missions along with building the shelters in this scenario, and a botched deflection mission could very plausibly deflect the asteroid off its predicted course and onto a new point of impact. So you want to be covered in case the point of impact isn't exactly where you think.

All of this is assuming that such a strike wouldn't trigger seismic activity, which I think it probably would, perhaps even setting off Yellowstone.

Compared to anything else, the Yellowstone supervolcano blowing up is a disaster. Compared to a dinosaur-killer going off anywhere on the same continent, it really isn't.