# The sun will go out tomorrow! **URL:** \ **Category:** Factual Questions\ **Created:** [January 12, 2012, 5:53pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318 "2012-01-12T17:53:11Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Lobohan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobohan/32/79_2.png) [@Lobohan](https://boards.straightdope.com/u/Lobohan)\ **Post date:** [January 12, 2012, 5:53pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/1 "2012-01-12T17:53:11Z")
I was just reminded of a question I had and decided to put you alpha-noodles to work. Say I purchased a device from Skald that allows me to instantly suppress the fusion in the Sun and vent the existing heat into another dimension. I flick the switch and the Sun turns off and becomes a ball of mostly hydrogen at room (space) temperature. How long does it take for the Earth to cool? Does the atmosphere instantly collapse into a liquid or ice? Seems unlikely, since we need to radiate our heat away. Does it take days, weeks or whatever? Bonus question: How large and and what distance would a Sun shield (say an opaque polymer sheet) need to be to block off our sunlight? I imagine it can’t be too close to the Sun, because the light would hit the Earth from around the sheet. And I suspect it could just be 8,000 miles and in near Earth orbit, but I’m trying to do this on a budget and want to purchase the smallest possible sheet. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [January 12, 2012, 6:04pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/2 "2012-01-12T18:04:13Z")
I think if you look at how quickly the temperature drops off at night that will give you a rough indication of how quickly the earth overall would cool. You’ll notice a temperature drop daily, but it will take several days before everything really starts to freeze. The sun is bigger than the earth, so in order to completely block it from the earth, you need a sheet that is the size of the earth’s diameter when it is near the earth, or the size of the sun’s diameter when it is near the sun, and sized proportionally according to the distance anywhere in between. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 12, 2012, 6:04pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/3 "2012-01-12T18:04:56Z")
It’s been a while since I’ve seen the actual calculation, but it’d be of order a week or so. For comparison, consider how much colder it gets at night than in day in a desert (a desert is the proper comparison because the moisture would precipitate out of the atmosphere first). For the bonus question, the smallest sheet would be just a tad larger than the Earth and right next to the planet, but that would require some sort of rockets or the like to keep it in place. A better bet would be to put it at the L1 Lagrange point of the Sun and Earth, which is still pretty close, but where an object would stay on its own (you’d still need stationkeeping thrusters, since it’s an unstable point, but those could be much smaller, as long as you use them precisely). ---
**Author:** ![TerpBE](https://avatars.discourse-cdn.com/v4/letter/t/bc8723/32.png) [@TerpBE](https://boards.straightdope.com/u/TerpBE)\ **Post date:** [January 12, 2012, 6:09pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/4 "2012-01-12T18:09:12Z")
The size of the shield would depend on the distance from Earth, and would need to be 2 \* Re + ((Rs-Re) \* (distance between shield and Earth’s center)) / (distance between Earth and Sun) Where Re and Rs are the radii of the Earth and Sun, respectively. So the closer to the Earth you are, the smaller your shield can be. However, you have to be at least “Re” away from the center. (note: this assumes a spherical Earth and Sun, which should be a reasonable approximation for this problem) ---
**Author:** ![Skammer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skammer/32/143_2.png) [@Skammer](https://boards.straightdope.com/u/Skammer)\ **Post date:** [January 12, 2012, 6:10pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/5 "2012-01-12T18:10:03Z")
I’m picturing the OP sung by a little red-haired orphan. _The sun will go out, tomorrow! Bet your bottom dollar that tomorrow There’s no sun._ ---
**Author:** ![Suburban\_Plankton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/suburban_plankton/32/219_2.png) [@Suburban\_Plankton](https://boards.straightdope.com/u/Suburban_Plankton)\ **Post date:** [January 12, 2012, 7:25pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/6 "2012-01-12T19:25:21Z")
I wonder… If we perform the maneuver indicated in the OP, leaving us with 4.73 gazillion tons of mostly ‘cold’ hydrogen just hanging around in space, wouldn’t gravity cause said hydrogen to spontaneously begin fusing again? And if so, how long before the sun returned to ‘normal’? ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [January 12, 2012, 7:39pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/7 "2012-01-12T19:39:07Z")
> [@Suburban\_Plankton](#): > > I wonder… > > If we perform the maneuver indicated in the OP, leaving us with 4.73 gazillion tons of mostly ‘cold’ hydrogen just hanging around in space, wouldn’t gravity cause said hydrogen to spontaneously begin fusing again? And if so, how long before the sun returned to ‘normal’? Kind of, yeah. Gravity pulls the gas inwards, which causes it to compress, which results in heat. When heat and pressure get high enough, you have fusion, which causes even more heat. This extra heat causes a steady state scenario where gravity is balanced by pressure and you get a star that remains stable for a very long time. When the fusion fuel is used up, the star begins contracting again. Eventually, when it’s totally out of fuel, it collapses into degenerate matter - a white dwarf, neutron star or black hole, depending on matter. So… if you were really sucking every bit of heat out of the sun through some magical device and you continued sucking out all new heat, it would collapse into a white-dwarf-like object. Of course, it wouldn’t be white (no heat to make it glow) and it would have a different chemical composition than a normal white dwarf. On the other hand, if the magic heat-sucking device wasn’t continuous, you’d get re-ignition as the sun collapsed. You’d also probably some pretty impressive explosions (perhaps something like a nova) as things tried to stabilize. No idea of the time scale on that. ---
**Author:** ![robert\_columbia](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@robert\_columbia](https://boards.straightdope.com/u/robert_columbia)\ **Post date:** [January 12, 2012, 8:03pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/8 "2012-01-12T20:03:01Z")
> [@Skammer](#): > > I’m picturing the OP sung by a little red-haired orphan. > > _The sun will go out, tomorrow! > Bet your bottom dollar that tomorrow > There’s no sun._ It’s the dark world life! ---
**Author:** ![Clark\_Cello](https://avatars.discourse-cdn.com/v4/letter/c/58f4c7/32.png) [@Clark\_Cello](https://boards.straightdope.com/u/Clark_Cello)\ **Post date:** [January 12, 2012, 8:15pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/9 "2012-01-12T20:15:02Z")
There is a fairly long thread on the sun topic from a year or two ago, but I hate searching, so you will have to find it yourself. ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [January 12, 2012, 8:57pm UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/10 "2012-01-12T20:57:20Z")
The Simpsons already did it! ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [January 13, 2012, 12:11am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/11 "2012-01-13T00:11:15Z")
> [@Lobohan](#): > > Bonus question: How large and and what distance would a Sun shield (say an opaque polymer sheet) need to be to block off our sunlight? That polymer sheet is absorbing the same energy that currently gets received over the entire planets surface and as I understand it radiating heat into a vacuum is a bitch. Wouldn’t it just continuously heat up until it dissolves into a plasma? Perhaps you’d need something much bigger which revolves so that the side not in direct sunlight can radiate heat and cool down? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 13, 2012, 12:41am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/12 "2012-01-13T00:41:16Z")
> [@](#): > > That polymer sheet is absorbing the same energy that currently gets received over the entire planets surface and as I understand it radiating heat into a vacuum is a bitch. Wouldn’t it just continuously heat up until it dissolves into a plasma? The hotter it gets, the easier it is to radiate away heat, so it’ll come to an equilibrium temperature. Since the Earth is in approximately the same situation, a first approximation would be that the equilibrium temperature would be roughly the same as the average temperature of the Earth. You could make it more effective, though, by making it shiny (so it would reflect away the heat instead of absorbing it). ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [January 13, 2012, 1:27am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/13 "2012-01-13T01:27:41Z")
> [@Chronos](#): > > The hotter it gets, the easier it is to radiate away heat, so it’ll come to an equilibrium temperature. Since the Earth is in approximately the same situation, a first approximation would be that the equilibrium temperature would be roughly the same as the average temperature of the Earth. You could make it more effective, though, by making it shiny (so it would reflect away the heat instead of absorbing it). Using some different numbers, Earth’s moon will hit 225 F during the day, so we could use that as an approximate maximum temperature for the polymer sheet hottest parts. While that’s hot for people, it’s pretty reasonable for planet-sized polymer sheets. ---
**Author:** ![OldGuy](https://avatars.discourse-cdn.com/v4/letter/o/3bc359/32.png) [@OldGuy](https://boards.straightdope.com/u/OldGuy)\ **Post date:** [January 13, 2012, 2:13am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/14 "2012-01-13T02:13:30Z")
> [@Chronos](#): > > For the bonus question, the smallest sheet would be just a tad larger than the Earth and right next to the planet, but that would require some sort of rockets or the like to keep it in place. A better bet would be to put it at the L1 Lagrange point of the Sun and Earth, which is still pretty close, but where an object would stay on its own (you’d still need stationkeeping thrusters, since it’s an unstable point, but those could be much smaller, as long as you use them precisely). This can’t be right. During a total eclipse the moon blocks virtually all of the sun and it’s definitely smaller than the Earth. ---
**Author:** ![Lord\_Feldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lord_feldon/32/341_2.png) [@Lord\_Feldon](https://boards.straightdope.com/u/Lord_Feldon)\ **Post date:** [January 13, 2012, 2:17am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/15 "2012-01-13T02:17:05Z")
> [@OldGuy](#): > > This can’t be right. During a total eclipse the moon blocks virtually all of the sun and it’s definitely smaller than the Earth. But it only has that effect over a very small area of the Earth. ---
**Author:** ![Gagundathar](https://avatars.discourse-cdn.com/v4/letter/g/a183cd/32.png) [@Gagundathar](https://boards.straightdope.com/u/Gagundathar)\ **Post date:** [January 13, 2012, 2:25am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/16 "2012-01-13T02:25:22Z")
Goodness gracious. The topics I find here are fascinating. My wild guess is similar to **Chronos’s**. About a week would find us having serious issues with atmospheric gases precipitating. There was a SF story long ago that dealt with this quite well. A family was able to make it through incredible ingenuity. I remember the son leaving the shelter to bring back frozen oxygen. Dang if I can recall the name of the story, but every time when it gets REALLY cold, I remember that story. Anyone with mad google-fu could probably get the ref. ---
**Author:** ![Lukeinva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lukeinva/32/17872_2.png) [@Lukeinva](https://boards.straightdope.com/u/Lukeinva)\ **Post date:** [January 13, 2012, 2:30am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/17 "2012-01-13T02:30:01Z")
Sorry can’t help ya. ---
**Author:** ![brocks](https://avatars.discourse-cdn.com/v4/letter/b/7feea3/32.png) [@brocks](https://boards.straightdope.com/u/brocks)\ **Post date:** [January 13, 2012, 2:47am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/18 "2012-01-13T02:47:12Z")
> [@Lord\_Feldon](#): > > But it only has that effect over a very small area of the Earth. On the other hand, the earth completely blocks the sun from the moon during a total lunar eclipse. I dimly recall that we have laser reflectors and stuff on the moon. Did NASA by any chance leave a thermometer up there? It would be interesting to see how fast the temperature falls during a lunar eclipse. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [January 13, 2012, 3:08am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/19 "2012-01-13T03:08:26Z")
Somewhere I remember seeing a calculation that it would take the oceans about 10 years to freeze over if the sun stopped shining. The atmosphere won’t freeze out until that happens. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 13, 2012, 6:18am UTC](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318/20 "2012-01-13T06:18:27Z")
> [@](#): > > There was a SF story long ago that dealt with this quite well. [A Pail of Air](http://en.wikipedia.org/wiki/A_Pail_of_Air), by Fritz Leiber. [Next page](https://boards.straightdope.com/t/the-sun-will-go-out-tomorrow/609318.md?page=2)