If the sun burned out tomorrow at noon, how long would civilization survive?
Until they unscrewed it , got out the replacement Sun, and screwed it in.
How many people does it take to screw in a replacement Sun?
I guess I was hoping for a serious reply from someone.
You’ll get one. Just wait a bit.
I doubt we’d last a year. Most plants would either die or go dormant inside of a month or so; the animals which live on them, a month or so after than. Meanwhile, it’ll start to cool off fairly quickly, as surface heat is radiated into space but no more is coming in. We’d enter a permanent winter within a couple months, and the temperature would continue to drop steadily. At some point, the temperature will bottom out as the heat leaking out from under the crust balances out what gets radiated away, but at that point, most higher life will be dead anyway. After a few (hundred?) million years, even the core will cool off enough so that the atmosphere will freeze out, leaving a bleak, dead world.
About eight and a half minutes.
Why are you so optimistic? We’d all be dead within a few weeks. The Earth would cool quickly and wouldn’t stop until it reached the temperature of deep space (-270C or 3K). The warmth from the oceans might buffer this effect in places on Earth.
We’d be lucky to rely on power stations to supply our homes with heat. I think there might be enough food reserves to last longer than a week but our main concern would be freezing to death.
Another thing you would notice is that it would snow continously. As the air cools, it would no longer be able to hold its moisture.
Yes. Depending on where it was “noon” at the time. As soon as people could see what was happening, it would be the immediate end of “civilization.”
It might be possible for a relatively small number of people to survive for some years using fossil fuels for heat and lighting. Inside a coal mine might be good, with occasional forays to the surface to scavenge. But only a few very lucky and inventive people would be able to do this, and even they might find things getting tougher and tougher as surface temnperature dropped.
Sans Sun, the Earth would freeze rapidly. We’re not talking about Antarctic winter cold, either, but cold like Triton. The atmosphere isn’t thick enough to provide much of a thermal blanket, nitrogen which comprises the bulk of the atmosphere would turn liquid, and possibly the oxygen as well until the atmosphere achieves a temperature/pressure equilibrium, leaving only a tenuous atmosphere of residual oxygen and nitrogen, maybe a little methane, plus whatever trace gases don’t freeze. Cigarette smokers, careful where you throw those butts; that liquid oxygen will cause easy fires, though they probably won’t last too long as the free oxygen will rapidly combine with any carbon compounds.
I once started to run a back-of-the-envelope calcuation based purely on radiative loss, and then realized that the emissivity will change dramatically once atmospheric gases start to condense. (I also couldn’t find an agreed upon number for the thermal load of the Earth, though I’m sure that climatologists or geophysicists must have a standard estimate.) Finger-in-the-wind guess is days rather than weeks, and certainly not months before you’re completely frozen. The amount of geothermal heating on the surface of the Earth is negligable, and energy loss will be progressive. Dirt is not an especially good thermal conduit, so it would take a while to cool but evaporative cooling as the atmosphere condenses will leach heat out quick, turning it into a tundra. The oceans might survive a bit longer, especially if an adiabatic layer of ice forms over and traps in the remaining liquid.
The only hope for the long term would be to enhance volcanism in an attempt to produce environmental heat. I’m not a geophysicist, nor do I play one in Intuitor.com’s #1 Insultingly Stupid Movie Physics Classic, but I doubt you could get anything like enough heat to keep the atmosphere from freezing, much less make the surface habitable, so you’d have to tap the thermal energy to keep your underground shelters warm. (You wouldn’t want to live on the surface because lacking an atmosphere you’d be at hazard to meteor bombardment and cosmic radiation that is too energetic to be deflected by the magnetic field.)
Basically, we’d be fucked. Sweet dreams…
Stranger
Most people would die within the first few days to a week from the cold, and of those that are left, most will die within a year from starvation. Meanwhile, of course, everyone who hasn’t died yet are going to be fighting with each other to try to make sure they stay in that category. So in that sense, civilization would crumble pretty quickly.
However, you’d probably have some remnant vestige of humans, carrying on some sort of civilization, indefinitely. A few folks would be able to improvise arrangements where they could heat and light small areas where humans and their crops could survive. Eventually, these folks would meet up with each other, extend the artificially-powered areas, and somewhat repopulate the planet.
Until next July, when we collide with Mars.
Less than a day, certainly. The riots and mob hysteria would destroy Civilization long before the Earth could freeze.
Someone said that the sun would actually increase in size, and that Earth would be drawn to it and vaporize. Google how the sun works and then fate of the sun.
Wow, CalMeacham, you were right. Some GREAT replies.
As it is, entire communities of people are able to survive in northern Alaska for 2-3 months with no sunlight. However, those people are well prepared for those conditions compared to most of the rest of the Earth’s population. Billions would die in the first few weeks after no sunlight. Organized civilization in the mainstream world would end almost immediately.
A few of those who are better prepared* could likely last a few months until food supplies ran out.
*are well stocked on non-perishable foods, have weapons, experienced in cold weather survival, have sub-zero clothing, do not need medication or other accomodations of modern society, and have a well insulated building or bunker.
It would seem to me that once it got cold enough, cars would not start, no one would be able to move, food deliveries would cease, and in addition to the cold killing off a lot of people, the elimination of food supplies would also spell doom very quickly. Pipes would freeze so water would no longer be available either.
Well, it’s not that GREAT a question. A more plausible approach to a similar problem would be asking what would happen after a massive nuclear exchange kicked up sun-obscuring clouds of dust that lasted for years (something that a great many people spent a great many hours thinking about), or the strike of a massive comet causing a dinosaur-ish extinction event (which could happen without warning at any second, even before I finish this sentence… phew, made it).
Personal survival would depend hugely on being lucky enough to be close to, say, a hydroponic farm complex powered by a nuclear reactor. 
One might be able to last for years until the environment recovers. However, having the sun disappear means it all academic - long-term survival is moot. Some humans might hobble along a few years or decades, but the end is inevitable.
This is a Straight Dope perennial, someone asks a variant of this question a couple times a year. Someone might dig up some of the old threads.
But basically you’ve got a week or maybe two before things cool down to Antarctic temperatures all across the planet. Once you hit 60 below (the coldest it gets in my old hometown of Fairbanks AK) lots of ordinary technology just stops working. Cars won’t start anymore, water lines freeze up, metal and plastic items snap in half, outside fuel tanks clog and fuel lines freeze solid.
Even running your furnace night and day won’t help much if you don’t have an insulated house. And of course, you’re not going to get many more fuel deliveries, even if the heating oil company has fuel on hand they’re not going to give it to you. And the furnace won’t be much help once the atmosphere starts freezing out, even if you had essentially unlimited fuel and an airtight shelter, you need oxygen to run the furnace.
If you had the time before you froze to death, you could rig up a method of shoveling up frozen air and heating it for intake into your furnace system, but frozen air is going to be a limited resource. I’m not sure how thick an average layer is going to be, but once the bulk of the atmosphere is frozen out you’re not going to get any new deliveries. You’d have to send your air gathering machine farther and farther into the field.
If you were at a nuclear reactor you might be able to live until you starved to death. They have machine shops and engineers and technical people, I imagine they might be able to fabricate shelters heated electrically from the plant, and the plant itself might have enough fuel on hand to last quite a long time. There might be frozen food supplies left after most people have frozen to death. But scavenging that is going to be very hard, especially with no air. You can drive a car at 60 below as long as it starts warm. But a IC engine needs air. And you’ll need the equivalent of spacesuits to walk around. Perhaps these could be manufactured.
Ironically, places near arctic would be the best equipped for survival, it would be funny if the last surviving humans were the ones at the base at the south pole.
Well, if you’re talking about the Sun after its standard Main Sequence lifespan and into the red giant phase (about another 4-5 Byr), then yeah, the outer layers of the Sun will start to expand as hydrogen fusion ramps down; they’ll be pretty cool, actually, but will eventually ungulf the Earth and prevent it from radiating heat away. Plus, as the Sun starts hydrogen fusion, then the C-N-O cycle the radiant temperature will increase. This won’t “vaporize” the Earth, but it will probably drive off all volitiles and boil the oceans away, leaving it a lifeless rock circling a (greenish) white dwarf star that is slowly fusing the remaining elements into silicon, phosphorus, sulfer, chlorine, argon, et cetera on up to iron. An ignominious end for our favorite star.
Stranger