If the sun stopped producing energy how long would we live?

[Descartes]

Originally posted by: theNEOone
btw, you are all wrong. the sun will implode on itself, and then expand to several thousand times it volume and engulf the earth. by the time the earth is "swallowed" by the sun, we'll all be dead of course, i just don't know what would cause it though.....google, here i come.


=|


When the core runs out of hydrogen fuel, it will contract under the weight of gravity. However, some hydrogen fusion will occur in the upper layers. As the core contracts, it heats up. This heats the upper layers, causing them to expand. As the outer layers expand, the radius of the star will increase and it will become a red giant. The radius of the red giant sun will be just beyond the Earth's orbit. At some point after this, the core will become hot enough to cause the helium to fuse into carbon. When the helium fuel runs out, the core will expand and cool. The upper layers will expand and eject material that will collect around the dying star to form a planetary nebula. Finally, the core will cool into a white dwarf and then eventually into a black dwarf. This entire process will take a few billion years.

Please note that I said we will IGNORE the stellar evolution in this THOUGHT experiment. We're all very familiar with the evolution of stars such as the sun with a spectral class of 'G', but again, this is a thought experiment so we have to choose which variables to consider.

 

[theNEOone]

Originally posted by: rbloedow

Originally posted by: theNEOone
btw, you are all wrong. the sun will implode on itself, and then expand to several thousand times it volume and engulf the earth. by the time the earth is "swallowed" by the sun, we'll all be dead of course, i just don't know what would cause it though.....google, here i come.


=|

This isn't a discussion about how the sun would "die" and stop giving off energy, we've already stated that we're operating on the assumption of the sun ust stopping it's production of energy.

well that's stupid, because under this assumption the end of the world will be due to earth freezing over, when in fact it will be because earth boils over. when the core runs out of hydrogen fuel, it will contract under the weight of gravity. however, some hydrogen fusion will occur in the upper layers. as the core contracts, it heats up. even if we could somehow withstand the incredible heat of the sun, we would not survive. in about seven billion years, the sun's outer "atmosphere" will engulf the Earth. due to atmospheric friction, the earth will spiral into the sun and incinerate.


=|

 

[Descartes]

Originally posted by: DrPizza

Originally posted by: rbloedow

Originally posted by: DrPizza

Originally posted by: konichiwa

Originally posted by: Descartes
The distance from the sun to the earth is considered a single astronomical unit, and it would take the last bit of light from the sun about 8 seconds to reach us. This is of course assuming that the sun simply "burn out" and didn't follow the empirical stellar evolution of a white dwarf. Assuming that, the ambient temperature would be little more than absolute zero, Kelvin; roughly the same temperature as observed in the cosmic microwave background. Since the 2nd law of thermodynamics says heat transfers spontaneously from a hot to a cold medium, I would *think* the thermal capacity of the earth would be high enough to sustain an existence for a couple of seconds? It can be quantitatively measured, but I don't know what the respective values.

I'm with him.

I'm not... for starters, the speed of light is 3x10^8 meters per second... it would take approximately 490-500 seconds (8 minutes, not seconds) to reach the earth.

Most people on earth would still be alive after a week or so, then they'd begin to die off. Most of the rest of what happens would depend highly on how society breaks down. There's no reason to believe that some populations couldn't survive indefinitely. But they'd be very sheltered, most likely heading underground as rapidly as possible to take advantage of the heat that the earth produces itself (radioactive decay within the earth) As far as food goes, the surface of the earth would basically be one giant freezer filled with all sorts of food (including frozen human, should the survivors get so desperate - which I doubt) But, with nuclear power and fossil fuels, we'd be able to keep warm enough to live, with enough electricity to power some well insulated "green houses."
Think about it... we have scientific bases on Antartica where the sun already *IS* out for 6 months of the year.

I don't think your realizing how cold it will get. There's a HUGE difference between Antarctica and a few degree from absolute zero. Seriously, machines would stop working, and no amount of insulation coud keep you from freezing. As stated above, matter almost stops moving at the temperature, how do you think we would retrieve food and supplies from the surface of the earth? Also, you're going to have to bury yourself very deep into the earth, which would be nearly impossible.

I just checked a couple of other resources (this isn't the first time the question has ever come up)... most agree on a 6 months to 1 year before the earth dropped to 150Kelvin. Good point on retrieving food from the surface of the earth! That won't work. And a little more thought on the atmosphere.. there's no way there'd be enough radiational heating from geothermal energy to keep the atmosphere from precipitating. The only way humans could survive in the long run would be if we had been prepared beforehand. An appropriate shelter couldn't be built in the time span left while such could be built. However, I think the estimates on the final temperature of the earth are a little low (2K). Example: One of the moons orbiting Jupiter probably has liquid water under the ice... That isn't heated from the sun, but from stresses caused by Jupiter's gravity.

6 months sounds like a long time considering the infinitessimal nature of most cosmic reactions. Do you have the resources in question? I'm just curious what they accounted for in determining such length.

 

[Descartes]

Originally posted by: theNEOone

Originally posted by: rbloedow

Originally posted by: theNEOone
btw, you are all wrong. the sun will implode on itself, and then expand to several thousand times it volume and engulf the earth. by the time the earth is "swallowed" by the sun, we'll all be dead of course, i just don't know what would cause it though.....google, here i come.


=|

This isn't a discussion about how the sun would "die" and stop giving off energy, we've already stated that we're operating on the assumption of the sun ust stopping it's production of energy.

well that's stupid, because under this assumption the end of the world will be due to earth freezing over, when in fact it will be because earth boils over. when the core runs out of hydrogen fuel, it will contract under the weight of gravity. however, some hydrogen fusion will occur in the upper layers. as the core contracts, it heats up. even if we could somehow withstand the incredible heat of the sun, we would not survive. in about seven billion years, the sun's outer "atmosphere" will engulf the Earth. due to atmospheric friction, the earth will spiral into the sun and incinerate.


=|

How much faster would the earth have to rotate before you fell over? Oh, that's absurd. No, it's a thought experiment. Science is full of thought experiments that have no empirical relevancy (e.g. Schroedinger's Cats, at least initially). Just have fun with it.

 

[EyeMWing]

Civilization - 5 minutes.
Most of population - an hour
Small pockets - a year, or however long it takes the atmosphere to precipitate.

If I were in charge of the world at that point, I'd just turn the nuclear weapons on the entire of civilization. Put them out of their misery. "Uh, where'd the sun go." "NUKES. NOW!"

 

[Amorphus]

the heat from the earth would not immediately disperse. while the heat transfer begins immediately, it still takes time for heat to transfer, and during that time (I have no idea how much time this is), it shouldn't cool to such extreme lows (2K) that we're talking about.

 

[DrPizza]

Originally posted by: EyeMWing
Civilization - 5 minutes.
Most of population - an hour
Small pockets - a year.

If I were in charge of the world at that point, I'd just turn the nuclear weapons on the entire of civilization. Put them out of their misery. "Uh, where'd the sun go." "NUKES. NOW!"

Actually, if the sun only went out for one hour, it'd have very little effect on us. Maybe a little bit of weather changes.. (of course, a butterfly could change the weather)

 

[zephyrprime]

6 months sounds like a long time considering the infinitessimal nature of most cosmic reactions. Do you have the resources in question? I'm just curious what they accounted for in determining such length.

What does the speed of cosmic reactions have to do with it? Everything won't die the second after the sun "turns off" anymore than they do during the night time when the far side of the earth sees no sun. Even if the sun turns off suddenly, the atmosphere and surface would take a macroscopic amount of time to radiate its heat away.

 

[Vic]

Think about it: solar eclipse - the sun DOES go out for a few minutes every now and then

Heh... caught your edit, DrPizza 😀
Solar eclipses don't affect the whole earth, just a VERY tiny portion (of course you know that or else you wouldn't have editted it out 😉 ).

 

[EyeMWing]

Originally posted by: DrPizza

Originally posted by: EyeMWing
Civilization - 5 minutes.
Most of population - an hour
Small pockets - a year.

If I were in charge of the world at that point, I'd just turn the nuclear weapons on the entire of civilization. Put them out of their misery. "Uh, where'd the sun go." "NUKES. NOW!"

Actually, if the sun only went out for one hour, it'd have very little effect on us. Maybe a little bit of weather changes.. (of course, a butterfly could change the weather)

Yes, but consider the effect of an unscheduled, sudden eclipse. The worst of human nature would come out very quickly, considering the state of our society.

 

[Descartes]

Originally posted by: Amorphus
the heat from the earth would not immediately disperse. while the heat transfer begins immediately, it still takes time for heat to transfer, and during that time (I have no idea how much time this is), it shouldn't cool to such extreme lows (2K) that we're talking about.

Not such lows immediately, no; however, consider that the radiant heat of earth would have to reach equilibrium with the entire universe at a temperature of about 2.75K. Consider that heat transfer considers the kinetic energy of the molecules in the fluid and not the temperature.

 

[K1052]

Originally posted by: rbloedow

Originally posted by: K1052

Originally posted by: rbloedow

Originally posted by: DrPizza

Originally posted by: konichiwa

Originally posted by: Descartes
The distance from the sun to the earth is considered a single astronomical unit, and it would take the last bit of light from the sun about 8 seconds to reach us. This is of course assuming that the sun simply "burn out" and didn't follow the empirical stellar evolution of a white dwarf. Assuming that, the ambient temperature would be little more than absolute zero, Kelvin; roughly the same temperature as observed in the cosmic microwave background. Since the 2nd law of thermodynamics says heat transfers spontaneously from a hot to a cold medium, I would *think* the thermal capacity of the earth would be high enough to sustain an existence for a couple of seconds? It can be quantitatively measured, but I don't know what the respective values.

I'm with him.

I'm not... for starters, the speed of light is 3x10^8 meters per second... it would take approximately 490-500 seconds (8 minutes, not seconds) to reach the earth.

Most people on earth would still be alive after a week or so, then they'd begin to die off. Most of the rest of what happens would depend highly on how society breaks down. There's no reason to believe that some populations couldn't survive indefinitely. But they'd be very sheltered, most likely heading underground as rapidly as possible to take advantage of the heat that the earth produces itself (radioactive decay within the earth) As far as food goes, the surface of the earth would basically be one giant freezer filled with all sorts of food (including frozen human, should the survivors get so desperate - which I doubt) But, with nuclear power and fossil fuels, we'd be able to keep warm enough to live, with enough electricity to power some well insulated "green houses."
Think about it... we have scientific bases on Antartica where the sun already *IS* out for 6 months of the year.

I don't think your realizing how cold it will get. There's a HUGE difference between Antarctica and a few degree from absolute zero. Seriously, machines would stop working, and no amount of insulation coud keep you from freezing.

Active heating would work though.

Nuclear would be the way to go. Plenty of enriched plutonium and uranium around.

But do you understand that we'd have no way to run our current nuclear power plants? There's not enough insulation around them to support human operation, and at that temperature, you wouldn't be able to control any mechanical devices to run the place since matter slows down so much near absolute zero.

Yes, I understand that.

What I would recommend is to find a large subterranean area to set up a habitat. The fastest way would probably be to cut open nuclear subs and pull out the plants. Then install an electric heating system that would keep the machinery and population warm.

 

[FFactory0x]

Guys Seriously I dont think anyone except a few know what there saying. After the 8 min are up we will instanly freeze like icecubes. No grdually but instanltly. Absolute zero is like 10000 below zero. Even if you ran to get in a tunnel you would freeze like the t-1000 mid run. No one on the surface would make it!!!!!!!!!!!!!!!!

 

[DrPizza]

Found what I thought was a really good source:
Quirks and Quarks radio show
Just listen to the real audio or get the mp3... it's the second thing on the show.

Several weeks to a month before we reached 32 Farenheit... The atmosphere will act as an insulator... As the atmosphere cools, water will condense, releasing the heat which evaporated it in the firstplace, further keeping the earth warm... Weather forecast: storms of Biblical proportions, all in the dark.



BTW, for the 8 minute thing above.... The sun would continue to warm the earth during those first 8 minutes it was out... the heat from the sun (infrared radiation) takes just as long to get here as the visible light.

 

[DrPizza]

Originally posted by: Vic

Think about it: solar eclipse - the sun DOES go out for a few minutes every now and then

Heh... caught your edit, DrPizza 😀
Solar eclipses don't affect the whole earth, just a VERY tiny portion (of course you know that or else you wouldn't have editted it out 😉 ).

aarghhh! I hit reply, then said "oh sh!t" and immediately hit edit. You got me though 🙂 A big "duh" moment.

 

[Descartes]

Originally posted by: DrPizza
Found what I thought was a really good source:
Quirks and Quarks radio show
Just listen to the real audio or get the mp3... it's the second thing on the show.

Several weeks to a month before we reached 32 Farenheit... The atmosphere will act as an insulator... As the atmosphere cools, water will condense, releasing the heat which evaporated it in the firstplace, further keeping the earth warm... Weather forecast: storms of Biblical proportions, all in the dark.



BTW, for the 8 minute thing above.... The sun would continue to warm the earth during those first 8 minutes it was out... the heat from the sun (infrared radiation) takes just as long to get here as the visible light.

Not to be pedantic, but infrared is still "light"; all propagate at c in vacuo. The universe isn't a perfect vacuum (not absolute zero), and our atmosphere is full of particulates with different refractive indexes that affect the speed of light. So, it won't get here at *exactly* the same time, but the difference is, as I had said earlier, so infinitessimal that it's safe to assume it does.

 

[DrPizza]

Anyone know how long a nuclear sub can stay down? Most likely the oceans would remain liquid indefinitely near thermal vents.

 

[Walleye]

Originally posted by: Richdog
Well if we chained all of ATOT together to some strange generator, the energy produced from their frantic 'self-stroking' could probably power the world for years to come.:beer:

work would become a very happy place 😛


er... that is when "space playboy" comes out...

 

[K1052]

Originally posted by: DrPizza
Anyone know how long a nuclear sub can stay down? Most likely the oceans would remain liquid indefinitely near thermal vents.

Depends on food supply. The reactors are good for several years before they would need to be refueled.

 

[Walleye]

Originally posted by: Vic

Originally posted by: konichiwa
I'm not sure I follow you Vic.

When we "realize" that the sun is no longer producing energy, that 8 minutes 20 seconds has already elapsed and the LAST bit of energy the sun produced has just hit the earth.

So, in effect, we would have the sun's energy for 8 minutes, 20 seconds after it stopped producing energy, because the energy it had already produced would be still travelling to us...

right?

Correct.

At which point the earth would suddenly be surrounded by a very large amount of cold space (2 degrees Kelvin IIRC). The energy dissapation would be quite rapid. How rapid, I don't know. A big factor would be whether the sun and its gravity well was still there or not.

earth is surrounded by a vacuum. there will be no heat transfer, all heat on earth will stay on earth except for the slow process of radiating off. how do you think white dwarfs stay for such a long time? they're on just built up heat at that point, not even burning any fuel.

 

[Descartes]

Originally posted by: Walleye

Originally posted by: Vic

Originally posted by: konichiwa
I'm not sure I follow you Vic.

When we "realize" that the sun is no longer producing energy, that 8 minutes 20 seconds has already elapsed and the LAST bit of energy the sun produced has just hit the earth.

So, in effect, we would have the sun's energy for 8 minutes, 20 seconds after it stopped producing energy, because the energy it had already produced would be still travelling to us...

right?

Correct.

At which point the earth would suddenly be surrounded by a very large amount of cold space (2 degrees Kelvin IIRC). The energy dissapation would be quite rapid. How rapid, I don't know. A big factor would be whether the sun and its gravity well was still there or not.

earth is surrounded by a vacuum. there will be no heat transfer, all heat on earth will stay on earth except for the slow process of radiating off. how do you think white dwarfs stay for such a long time? they're on just built up heat at that point, not even burning any fuel.

What do you think radiation is?

I'd also like to add that the the first white dwarf star I was able to look up is in NGC6937; it has a surface temperature of ~18,273K. Consider that relative to the sun. Earth can't even be considered in the same context.

 

[EyeMWing]

Originally posted by: Walleye

Originally posted by: Vic

Originally posted by: konichiwa
I'm not sure I follow you Vic.

When we "realize" that the sun is no longer producing energy, that 8 minutes 20 seconds has already elapsed and the LAST bit of energy the sun produced has just hit the earth.

So, in effect, we would have the sun's energy for 8 minutes, 20 seconds after it stopped producing energy, because the energy it had already produced would be still travelling to us...

right?

Correct.

At which point the earth would suddenly be surrounded by a very large amount of cold space (2 degrees Kelvin IIRC). The energy dissapation would be quite rapid. How rapid, I don't know. A big factor would be whether the sun and its gravity well was still there or not.

earth is surrounded by a vacuum. there will be no heat transfer, all heat on earth will stay on earth except for the slow process of radiating off. how do you think white dwarfs stay for such a long time? they're on just built up heat at that point, not even burning any fuel.

The earth is not in a total vacuum. There are still the occasional atom of hydrogen or other misc particle floating around. It's about as close as you can get to a total vacuum, though.

 

[Walleye]

you guys do realize that theoretically, a person can survive in space w/o suit for around 30 seconds? it's not the temperature that kills you, it's the lack of atmosphere... a vaccuum causes your blood and brain fluid to boil, and the air in your lungs (however little of it there is) will instantantly expand beyond your lung capacity and cause you to have embalisms... i dont know why i say this, except that, if you're in the shade of the earth, it really doesnt matter, you wont die due to the temperature drop. everyone saying a constant heat source from the sun is vital to the survival of earth for more than a few seconds is a witless wonder. it amazes me that you idiots have survived this long.

anyway, heat stays built up in the atmosphere for a long time to come. some of the sun's energy bounces off, i have no real idea how much actually heats the earth, and how much of that constant sustained energy is responsible for stemming off the radiating away of heat. at such point where the sun goes out and the atmosphere does go cold, then the atmosphere becomes our greatest enemy, because convection is a much faster medium of heat dispersion than radiation. we'd survive longer in a vacuum than in the atmosphere, when it's at 2 degrees kelvin. except that it wont stay at 2 degrees kelvin, because of the temperature of earth's core would still heat the earth. how much, i have no idea... but since absolute zero is between 200 and 500 degrees below zero in farenheight, i'll venture a guess that the core would keep us at a steady -150 degrees farenheight for some time to come.

i guess the pressing question is whether the sun is responsible for earth's core still being molten.

 

[NickE]

Originally posted by: FFactory0x
Guys Seriously I dont think anyone except a few know what there saying. After the 8 min are up we will instanly freeze like icecubes. No grdually but instanltly. Absolute zero is like 10000 below zero. Even if you ran to get in a tunnel you would freeze like the t-1000 mid run. No one on the surface would make it!!!!!!!!!!!!!!!!

No we wouldn't - first off, absolute zero is zero Kelvin which equals -273.15°C. Second, it's going to take quite a while for the atmosphere to cool down anything like that amount; the combined heat capacities of the atmosphere, land mass and oceans is going to take quite some time to radiate away, convection will keep things reasonably evenly distributed for a while as well.
As the oceans cool down, so the densest water (4°C) will occupy a greater and greater depth, freezing takes place from above and since ice is a very poor conductor complete freezing would take a long time. As someone mentioned earlier, Europa (Jovian satellite) is thought to have liquid water under an ice layer, kept liquid by tidal stresses from Jupiter. Although the tidal force from the Moon on the Earth is much less than that of Jupiter on the Galilean satellites, it should still be able to maintain some liquid water. So, looks like the dolphins had it right all along - 'So long, and thanks for all the fish' as they head for the depths with their cunningly devised breathing tubes.

 

[Walleye]

Originally posted by: Descartes

Originally posted by: Walleye

Originally posted by: Vic

Originally posted by: konichiwa
I'm not sure I follow you Vic.

When we "realize" that the sun is no longer producing energy, that 8 minutes 20 seconds has already elapsed and the LAST bit of energy the sun produced has just hit the earth.

So, in effect, we would have the sun's energy for 8 minutes, 20 seconds after it stopped producing energy, because the energy it had already produced would be still travelling to us...

right?

Correct.

At which point the earth would suddenly be surrounded by a very large amount of cold space (2 degrees Kelvin IIRC). The energy dissapation would be quite rapid. How rapid, I don't know. A big factor would be whether the sun and its gravity well was still there or not.

earth is surrounded by a vacuum. there will be no heat transfer, all heat on earth will stay on earth except for the slow process of radiating off. how do you think white dwarfs stay for such a long time? they're on just built up heat at that point, not even burning any fuel.

What do you think radiation is?

idiot... do you know what the word EXCEPT means?

it means i am noting an exception to my rule...

jeez...