How long would we live if the sun just went out?

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tpeezy

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OK I know that there is .0000000000000000000000001% chance of this happening because most likely the sun will go to a red giant, and then supernova, but I was curious how long would we humans live if the sun just went poof, and went out like someone turned off the lights. I know it would probably take what 6min or so for the light to reach us for us to know, but how long would the earth's residual heat keep us warm enough to survive? My guess which is probably wrong is that we wouldnt live long maybe a few days, because if you look at how much the temp goes down even at night time 20 or so degrees after the sun was out 8 hr beforehand, it seems like it would be well below freezing within 2-3 days or so. This is a total hypothetical question, and I know its kind of stupid, but sometimes I just think of weird things, and I am curious about stupid stuff like this.
 
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Fomalhautian

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Holly Otterbein":1lqh9por said:
If you put a steamy cup of coffee in the refrigerator, it wouldn’t immediately turn cold. Likewise, if the sun simply “turned off” (which is actually physically impossible), the Earth would stay warm—at least compared with the space surrounding it—for a few million years. But we surface dwellers would feel the chill much sooner than that.

Within a week, the average global surface temperature would drop below 0°F. In a year, it would dip to –100°. The top layers of the oceans would freeze over, but in an apocalyptic irony, that ice would insulate the deep water below and prevent the oceans from freezing solid for hundreds of thousands of years.

LNK TO ARTICLE

Looks like submarines are our best bet.
 
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neilsox

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Thank you Formal: It is refreshing to get a reply with numbers instead of generalities. Neil
 
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MeteorWayne

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Actually there are quite a few generalities in that article, like "within a week", "0 F", "in a year", "-100F", "millions of years after that", "-400F", etc :)
 
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SpaceTas

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Digging deep and using the heat of the Earth would work, but you need to beat the air freezing.
It would be easier in an active geothermal area; hot tub anyone :D
 
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neilsox

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Hi MeteorWayne: I agree the numbers in the article are guesstimates, and possibly way off = thousand percent, but they are numbers, unlike cold, soon, quickly, long term etc. which are generalities which can (14.22% of the time) be interpreted with numbers plus or minus a million percent. I hope you agree plus or minus a million percent is not very helpful, but plus or minus 1000 percent is better 71 % of the time. The imagination can go wild with generalities 23% of the time. I'm guesstimating, but they are not generalities. Neil
 
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MeteorWayne

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Dictionary definition:

2 a : generalization : a vague or inadequate statement
 
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ZenGalacticore

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Eight minutes. Maybe a few more with the "residual heat" of the Earth.

I was in Washington D.C. when the almost total eclipse of the Sun occurred back in 1984. For those few moments that the sun was occulted, the temperature dropped at least ten degrees, or felt like it. It got cold real fast.
 
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Ruri

Guest
I'd say the atmosphere would start freezing out after a few months this would be the end of all surface life including humans.

But the oceans could take millenia or more to freeze and internal heat could keep some of it liquid for billions of years.

In short the Earth would pretty much turn into a giant version of Europa after a few years.

Microorganisms and other simple life such as that found around geothermal vents could survive for millions of years.

The oceans would become oxygen poor as there will be no mixing with the atmosphere to replenish it so complex life would die out fairly quickly.
 
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SpeedFreek

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ZenGalacticore":3tv6mnt3 said:
Eight minutes. Maybe a few more with the "residual heat" of the Earth.

I was in Washington D.C. when the almost total eclipse of the Sun occurred back in 1984. For those few moments that the sun was occulted, the temperature dropped at least ten degrees, or felt like it. It got cold real fast.

What about when the Sun is around the other side of the planet for hours on end, i.e. at night? Or when it is dark for months at a time in arctic countries?
 
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SpaceTas

Guest
Here is a order of magnitude calculation for the Earths atmosphere to freeze (more generalities)

Lets start with the average temperature of the Earth as about 15 deg C or 287 Kelvin.
Lets take the cooling rate as that of a desert climate overnight: Say 24 deg C over 8 hours ie 3 deg C per hour.

Nitrogen becomes liquid at 77 Kelvin (freezing water is at 0 deg C or 272 Kelvin) so it would take very roughly (287-77)/3 = 70 hours (3 days).

Being an order of magnitude estimate I'd give this estimate an uncertainty of 7-10 hours.

Of course it would be way too cold well before that and this is a linear guesstimate. To do it properly you would need the heat energy stored in the atmosphere and apply the radiation laws (Boltzman) which govern how much heat is lost, as an object cools it looses energy more slowly. As different gasses freeze out the composition would change leading to different cooling rates. ie when water freezes out we loose that greenhouse gas upping the cooling rate. Last you need to include heat input from the Earth.
 
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SpaceTas

Guest
A side note: If the heat output from radioactive decay in a planet is high enough and the atmosphere is thick with greenhouse gasses it is possible to have a livable planet without a star. :cool:
 
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CosmicTrader

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Given that there really wouldn't be anything we could do about it and that none of us could go anyplace else, how much does it really matter? :mrgreen:
 
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Lord_Chaos

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Heinlein used that as a punishment in "Have Space Suit. Will Travel."
 
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BSJ

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Not very long! Al Gore would be against global warming. And that would be that! :mrgreen:
 
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UFmbutler

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I can't add anything more to this topic than what has already been said, but I believe I can direct you to a more knowledgeable source:

[youtube]http://www.youtube.com/watch?v=SRH-Ywpz1_I[/youtube]
 
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jamesandshari

Guest
Based upon common sense, experience, and known meteorological temperature decay I think there would be a series of powerful events as temperatures plummet very very fast over the whole planet. The first twenty four hours would be bearable but after that survivability suffers dramatically. The first twenty four hours the worldwide temperature drop may be around fifty degrees more or less according to geographical location. Next to warm seas the temperature would go down a little but mid-continent and desert regions would see over fifty degrees drop in temp. Many such regions would be below freezing, 32F, by the end of the first twenty four even at the equator in higher elevations away from the seas. Huge rain, hail, and snow blizzards kick in about that time as they flow in from the warm seas and ride up over cold air over the land masses. The equatorial rain forests get their first tastes of heavy snow during the second twenty four hours building up to yards deep rather then inches. After the second twenty four, now past forty eight hours, many interior and desert regions will be one hundred +- degrees F below where they were when it all started. Seas are cooling but more slowly. Blizzards and big bad hail storms at the sea shores continue to worsen. The tropical rain forests back from the coasts have twenty to thirty feet of snow upon them and there is no letup yet. The forth twenty four kicks in. Habitation at the surface becomes impossible and there was not time to prepare below ground sites except for a few already existing military sites. Another day or two and the interior continental air starts to freeze. Colder seas are now freezing over reducing the storms. The fifth day sees frozen atmosphere at and well below both poles and air rushes in to fill the void. Underground chambers cannot survive due to frozen air above and heaters becoming inoperable. Food, water, and energy supplies are no longer sustainable. Electricity was out at the surface on the second day while fuel and air runs out quickly under ground.
One week into the event sees a dead planet unless God prepares survival pockets for those he chooses to save. But this is not to say this will be his method We just do not know.
 
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orbitmath

Guest
A pretty good approximation: astronomical unit/speed of light = 92957000 miles/186282.4 miles/second = 499 seconds = 8.32 minutes for living beings. Brrrrr!
 
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qraal

Guest
Earth's atmosphere is 10.33 tons of N2/O2/Ar (plus tiny traces) for every square metre. At the top it radiates at an effective temperature of 255 K to balance the Sun's heat that's absorbed. That means a heat-loss rate of 240 W over every square metre of planet. At that temperature the emissivity is roughly the same all over the planet, close to 1, so it would radiate pretty evenly. Of course currently, in the Sun's shining, net heat-loss is from the upper parts of both hemispheres, while net heat gain is in the tropics. Without the Sun there's quite a lot of stored energy in the oceans to redistribute before everything starts freezing out.

Let's assume the atmosphere is on average at 260 K and it's radiating at 240 W. Each kg of air stores 1003 J/K over the temperature range in question, so there's ~2.7 GJ to radiate away at 240 W over every square metre. Thus ~11.2 mega-seconds, 130 days, to absolute zero. In reality the radiative power declines 1/T^4, so the air at 127.5 K is radiating just 1/16th of what it does at 255 K. To get from 255 to 127.5 K takes (2^3-1) times 130 days - 910 days. Roughly the same period again to drop to the condensation temperature of N2 at ~63 K. Past that point the equilibrium temperature of the Earth from its geothermal heat is ~33 K, and that's how cold the Earth will ultimately get.

But this neglects the heat from the oceans. What would happen, taking that into account, would be a net flow of warm air away from the oceans and cold air flowing towards them. The continental interiors would drop rapidly to ~250 K (-23 C or -9.4 F) and then remain there for as long as ocean heat could keep them "warm". As there's 4200 J stored in every kg of ocean for every K that could be for quite some time. There's much, much more heat in the oceans than there is in the atmosphere. A net flow of moisture, condensing out as snow and frost, will slowly create glaciers on the continents until the tops of the oceans freeze over and the ocean ice tops become as cold as the glaciers on land. That will take some time. A rough estimate would be to equate the energy difference stored in the oceans (which average 5 C temperature) with condensed water ice at ~250 K. The ocean water mass spread over the whole planet would be 2640 metres. Ice holds ~2 kJ/kg.K, energy of freezing (fusion) is 334 kJ/kg and 21 kJ/kg is stored as heat in 5 C water. Thus about 500 metres of glacial ice condensed from gas phase (2.3 MJ/kg) is the equivalent to the stored energy difference in the oceans. As the continental area is ~1/2 the oceans - accounting for exposure of the shelves as sea level drops - that means about 1 km of ice will eventually blanket the continents.

How long that'll take is probably ~centuries since all the heat released must trickle away at ~230 W from the top of the atmosphere to space. The slow decline to the liquefying and freezing of the N2/O2 will take a few millennia beyond that.
 
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ZenGalacticore

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SpeedFreek":1khk3z6y said:
ZenGalacticore":1khk3z6y said:
Eight minutes. Maybe a few more with the "residual heat" of the Earth.

I was in Washington D.C. when the almost total eclipse of the Sun occurred back in 1984. For those few moments that the sun was occulted, the temperature dropped at least ten degrees, or felt like it. It got cold real fast.

What about when the Sun is around the other side of the planet for hours on end, i.e. at night? Or when it is dark for months at a time in arctic countries?


That's a seemingly great thought and observation there, Speed. But I'm here to tell you, that I was there for this rare solar-eclipse event, and it got much colder real fast! Ask MeteorWayne or Dr. Wayne or whomever!

How dare you imply that I am making this up?

Have you ever experienced (in real life, on the ground, not in front of your keyboard) a near-total solar eclipse?

And btw, the drop in temp is probably localized to those areas that are at highest occultation. There's never a "total" solar eclipse for ALL lattitudes.

"i.e. at night"... Phsssssssssssst!!!
 
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MeteorWayne

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orbitmath":2xn0phg5 said:
A pretty good approximation: astronomical unit/speed of light = 92957000 miles/186282.4 miles/second = 499 seconds = 8.32 minutes for living beings. Brrrrr!

Just for fun, at this moment, distance 1.00091993 AU, ~ 151,000,000 km, light time 8m 23.6 seconds. :)
 
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MeteorWayne

Guest
Yes, the immediate drop in temperature in the umbra has been reported in eclipse reports for milennia.
You've got me curious, I'll check and see if any quantitative measurements have been made.

And it is colder at night, and it the polar regions in winter :)
 
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MeteorWayne

Guest
Not quantitative (still searching for that) from NASA:

http://sunearthday.nasa.gov/2006/faq.php

"Typically, how big a temperature drop do you get during a total solar eclipse?
It would probably be equal to the typical daytime minus nighttime temperature difference at that time of year and location on the Earth. It would be modified a bit by the fact that it only lasts a few minutes, which means the environment would not have had much time to thermally respond to its lowest temperature, so it would probably only be 3/4 or 1/2 the maximum day-night temperature difference. Because the patch of the shadow travels faster than the speed of sound, weather systems will only be affected very locally directly under the instantaneous footprint of the eclipse. The main effect is in the "radiant heating" component which goes away suddenly at the moment of eclipse and produces a very fast temperature decrease. If the wind is blowing, your body probably exaggerates, by evaporative cooling, how large the actual temperature swing actually is"
 
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