If the sun "went out"... [Archive] - Two Plus Two Newer Archives

Borodog

11-01-2006, 09:32 PM

The sun is out approximately half the day, every day, so clearly it won't be seconds, minutes, hours, or even days.

It might not even wipe us out. The Earth gets fairly hot fairly quickly as you dig down, and that internal heat is entirely due to radioactivity within the Earth.

The problem, of course, is that the entire food chain is based on photosynthesis. Most of the world would die, but there might be enough time for small groups to dig down deep and stockpile long enough to genetically engineer a heat based agriculture. Hard to say.

FortunaMaximus

11-01-2006, 09:47 PM

No, atmospheric heat spreads through the whole globe. The dissipation that occurs on the nightside is buffered by global wind currents.

Hmm. We certainly have the capability for geotherm solutions to heating, and you could sustain enough for centuries, perhaps, enough to get to Jupiter and tap that ridiculously rich hydrocarbon atmosphere.

As long as provisions were made beforehand for this unlikely eventuality, I think we'd be ok.

Odd. Was thinking of Vinge and the On/Off star. Hmph.

Borodog

11-01-2006, 09:58 PM

Vinge's On/Off star takes years to cool down until the atmosphere snows out, if you'll recall.

There is no way that the air on one side of the globe mixes with the air on the other side over the time scale of half a day, unless the wind is blowing at 1000 miles per hour.

FortunaMaximus

11-01-2006, 10:02 PM

-273 Celsius in space, yes?

Half the planet gets a barrage of sunlight half the day. yet you never get higher than 60 degrees Celsius around the equator.

Mean global temperature's what, 21, 22 degrees? Oh, -240-255 C should be the mean. Thinking of Pluto.

And accounting for greater geothermal heating, probably somewhat warmer than that. -220 maybe, which could be made more efficient over time. That'd be surface temperature, and certainly it'd be possible to make habs. And there would be huge amounts of oxygen to dredge in snowfall.

Borodog

11-01-2006, 10:14 PM

When the sun is directly overhead, the Earth receives a flux of about 1.4 kilowatts/meter^2. That's 14 100 Watt bulbs shining down on 1 square meter. The Earth's surface acts as a heat sink during the day, and reradiates this energy into the cooling atmosphere at night, slowing the rate of cooling. It has nothing to do with warm air mixing from the sunny side of the planet. Like I said, the wind does not blow at a thousand miles an hour. Most places it barely breaks 1% of that. It's totally negligable.

FortunaMaximus

11-01-2006, 10:20 PM

Yes, I'm aware. The atmosphere would dissipate over time, turning into frozen water and snow. The trapping effect would make subsurface structures livable with an efficient heat transfer infrastructure. Churn seawater or surface snow to create oxygen, use hollowed-out caverns as hydroponic farms. Propulsion would be unnecessary with a worldwide communication network. So there'd be a significant drop in population if that eventuality ever occured, but h. sap would be sustainable still, given forewarning and time to build the structures.

As you'll noticed, my second assessment of probable surface temperature discounted any kind of wind analysis. The surface wouldn't be livable.

Should we assume the mass of Sol remains static even if the production of energy diminishes to 0?

Borodog

11-01-2006, 10:26 PM

[ QUOTE ]
As you'll [have] noticed . . .

[/ QUOTE ]

Not really, since I can rarely follow what you're talking about.

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Should we assume the mass of Sol remains static even if the production of energy diminishes to 0?

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I don't see how you can. Without internal thermal support, it would gravitationally collapse.

FortunaMaximus

11-01-2006, 10:36 PM

Into what, a singularity? What, did the mass suddenly bluehift in the direction of Alpha C? /images/graemlins/confused.gif

Borodog

11-01-2006, 10:38 PM

[ QUOTE ]
Into what, a singularity? What, did the mass suddenly bluehift in the direction of Alpha C? /images/graemlins/confused.gif

[/ QUOTE ]

Don't ask me. It's not my hypothetical.

FortunaMaximus

11-01-2006, 10:44 PM

Mine either. <shrugs> I suppose Terra would just drift. Probably not that big a deal unless spin was a necessary component of the core heating processes.

evank15

11-01-2006, 10:46 PM

[ QUOTE ]
When the sun is directly overhead, the Earth receives a flux of about 1.4 kilowatts/meter^2. That's 14 100 Watt bulbs shining down on 1 square meter.

[/ QUOTE ]

A little math problem there, but ya, 1365 Wm^-2

evank15

11-01-2006, 10:49 PM

[ QUOTE ]
-273 Celsius in space, yes?

[/ QUOTE ]

No.

T=0K is an asymptote, do you see why?

Wiki "big bang" or "CBR".

Borodog

11-01-2006, 10:51 PM

Where's the math problem? Last time I checked 1.4 kilowatts ~ 1365 Watts. Or are you refering to the fact that all of the energy emitted by the lightbulbs doesn't actually fall straight down on the square meter? Because that's true; I was being slack to illustrate a point, it's not that high of an energy flux.

FortunaMaximus

11-01-2006, 11:00 PM

[ QUOTE ]
[ QUOTE ]
-273 Celsius in space, yes?

[/ QUOTE ]

No.

T=0K is an asymptote, do you see why?

Wiki "big bang" or "CBR".

[/ QUOTE ]

Quite [censored] irrelevant where the factors are concerned, as it's hardly a measureable effect in the scenario presented. Might as well use cat farts to bellows a candle.

Howya doin'?

evank15

11-01-2006, 11:03 PM

[ QUOTE ]
It might not even wipe us out. The Earth gets fairly hot fairly quickly as you dig down, and that internal heat is entirely due to radioactivity within the Earth.

[/ QUOTE ]

No. Earth's heat is almost entirely thermal. It does radiate a small amount (at ~10 microns), as you and I and everything in the universe does, but this is very small. And it most definitely is not radioactive, since we'd all have three eyes and fins (etc) if that was the case.

evank15

11-01-2006, 11:06 PM

[ QUOTE ]
Where's the math problem? Last time I checked 1.4 kilowatts ~ 1365 Watts. Or are you refering to the fact that all of the energy emitted by the lightbulbs doesn't actually fall straight down on the square meter? Because that's true; I was being slack to illustrate a point, it's not that high of an energy flux.

[/ QUOTE ]

Whoops, my bad. I saw 14 100 and took that to be 1.4E4, not fourteen 100W bulbs. MY bad.

I guess I'm just not used to the bastardized syntax neccesitated by today's keyboards and forum software.

Borodog

11-01-2006, 11:10 PM

[ QUOTE ]
[ QUOTE ]
It might not even wipe us out. The Earth gets fairly hot fairly quickly as you dig down, and that internal heat is entirely due to radioactivity within the Earth.

[/ QUOTE ]

No. Earth's heat is almost entirely thermal. It does radiate a small amount (at ~10 microns), as you and I and everything in the universe does, but this is very small. And it most definitely is not radioactive, since we'd all have three eyes and fins (etc) if that was the case.

[/ QUOTE ]

The Earth's core's "thermal heat" (don't you think that's a bit redundant and repetitive?) comes from radioactive decay deep in the Earth's core. The radioactive elements are generally heavier than iron, and during the formation of the Earth most sank to the middle, where they are happily decaying away, keeping the Earth's core molten. If it weren't for this effect the Earth's core would have long since cooled and stilled.

Edit: I see that this is actually not the in vogue theory. I'm pretty shocked, since this was standard in the text I learned form.

I concede the argument. My apologies.

evank15

11-01-2006, 11:12 PM

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
-273 Celsius in space, yes?

[/ QUOTE ]

No.

T=0K is an asymptote, do you see why?

Wiki "big bang" or "CBR".

[/ QUOTE ]

Quite [censored] irrelevant where the factors are concerned, as it's hardly a measureable effect in the scenario presented. Might as well use cat farts to bellows a candle.

[/ QUOTE ]

I don't understand what you're trying to say here.

You said the temperature in space is 0K. I'm saying that's not right. And in the neighbourhood of a star, it's not even close to right. Even in a galaxy in general, it's not even close to right.

Maybe I'm being picky, but I just don't like seeing fallacies being propogated. Believing absolute zero exists or an ideal gas exists, or a frictionless plane, or any other number of idealized concepts is just plain wrong. They are nice to use in physical problems, but they shouldn't be used when just doing hand wavy stuff, gedankenexperiments if you will.

FortunaMaximus

11-01-2006, 11:16 PM

Yeah, ok, fine. Carry on. If you demand precision in thought experiments, you might want to invest in a winch.

GL. Bored.

evank15

11-01-2006, 11:18 PM

I guess we don't know for sure, but as far as I know that's not the theory we were taught. But I'm a little hazy on geophysics to tell you the truth.

evank15

11-01-2006, 11:20 PM

[ QUOTE ]
Yeah, ok, fine. Carry on. If you demand precision in thought experiments, you might want to invest in a winch.

GL. Bored.

[/ QUOTE ]

Meh, maybe you're right.

My Flames just lost, that's why I'm being kind of irritating. [censored] Flames.

FortunaMaximus

11-01-2006, 11:21 PM

Leafs are treading water. Ugh. Naw worries.

Borodog

11-01-2006, 11:25 PM

[ QUOTE ]
I guess we don't know for sure, but as far as I know that's not the theory we were taught. But I'm a little hazy on geophysics to tell you the truth.

[/ QUOTE ]

Well, neither am I, but I checked wikipedia just to make sure I wasn't full of it, and unfortunately, I was. It mentions the radioactivity theory, but it seems to be a fringe thing. I really have to wonder how it made it into the Physical Science texts that I was teaching out of. /images/graemlins/blush.gif

It's so sad, because it's such a beautiful theory.

CORed

11-03-2006, 12:39 AM

I remember reading an old science fiction short story entitled "A pail of air", about a family that managed to survive the death of the sun. I believe it was written by Fritz Lieber. The title of the story came from the family's practice of periodically sending their kid outside in an insulated pressure suit to get a bucket of frozen air to replenish the supply in their pressurized house.

Hopey

11-03-2006, 03:40 PM

[ QUOTE ]
The problem, of course, is that the entire food chain is based on photosynthesis. Most of the world would die, but there might be enough time for small groups to dig down deep and stockpile long enough to genetically engineer a heat based agriculture. Hard to say.

[/ QUOTE ]

Given the choice, I think I'd rather die than live underground forever.

Would the underground society that you are envisioning be an AC society? /images/graemlins/smile.gif

Silent A

11-03-2006, 04:55 PM

To address the OP, the sun "turning off" would be pretty close to those nuclear winter and giant asteroid collison scenarios. Cooling of the earth would be rapid enough to prevent us from having enough time to save ourselves without preparing ahead of time.

The best estimate for cooling rates I can think of at the top of my head is the change in temperature between daytime and nightime at the centre of a large continent on a wind-free day. There are places on earth where this could easily reach 20 degrees celcius per day. 10 degrees would be pretty damn conservative unless you're near the equator and are close to the warm ocean (which would act like a heat source and slow everything down). Still, I'd have to say 2 degrees per day would be an absolute minimum rate of temperature decline. That means in about 2 or 3 weeks even the warmest places on earth, next to the warmest water bodies, will reach 0 deg C.

What you should get from this is that even though there are forms of life that could survive sub-zero temperatures for a long time, they aren't the ones that will be living in the tropics and artic life forms won't have time to migrate so within 2 or 3 weeks all surface life is screwed.

Deep underground it is more than warm enough and more than insulated enough not to depend on energy from the sun. Geothermal energy will be plentiful for such a long time that sociological needs of tiny isolated underground societies will have more impact on our long term chances of survival than our ability to keep ourselves warm and fed.

BigBuffet

11-14-2006, 11:14 AM

What if our universe rotates (every so often, say 26,000 years) through a part of the galaxy where electromagnetism doesn't work?

Instead of being wiped out we'd be Amish overnight. (No offense to Amish people, I just couldn't think of a better example).

No more wars. No more fighting about which religion is better. No more multinational corporations controlling our lives (same for Big Gov). Many would perish due lack of logistic for goods and services, but the survivors would be ok living a simpler life.

Question: Would you rather have the sun "burn out instantly" and perish or have all technology that relies on electricity become obsolete and thus have a 50-50 chance of surviving?

Brainwalter

11-14-2006, 11:24 AM

There were lots of wars before people used electricity.

madnak

11-14-2006, 11:29 AM

If electromagnetism "stopped working," a lack of technology would be the least of our problems.

FortunaMaximus

11-14-2006, 11:29 AM

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There were lots of wars before people used electricity.

[/ QUOTE ]

Were they fought in perfect darkness?

Brainwalter

11-14-2006, 11:33 AM

No.

(I suggest you read the post I was responding to.)

FortunaMaximus

11-14-2006, 11:34 AM

[ QUOTE ]
No.

(I suggest you read the post I was responding to.)

[/ QUOTE ]

I did. I wasn't referring to light. Consider how vital EM is to this biosphere.

Brainwalter

11-14-2006, 11:36 AM

You lost me.

FortunaMaximus

11-14-2006, 11:47 AM

It isn't the lack of light, but the lack of magnetism, Brainwalter, and those have would have deletrious effects on this planet too. Any sort of war would become redundant with population plunges, so even that would stop and the conflicts would be for resources to survive.

Amish? That's too [censored] optimistic. Try Paleolithic.

madnak

11-14-2006, 12:12 PM

Try pure chaos. Light is photons, the carriers of electromagnetic force. No photons, no light. Also, no atoms - the electrons are attracted to protons through electromagnetism. And no kinetic energy either - it's electromagnetic. Which means no heat, no Brownian Motion, you get the idea. I mean, what's left without electromagnetic force? The weak force, the strong force, gravity. Uhm... That's not a lot to work with. I can't even think what would happen to the world - matter is held together by the electromagnetic force. Would everything just collapse into a single point?

FortunaMaximus

11-14-2006, 12:56 PM

[ QUOTE ]
Try pure chaos. Light is photons, the carriers of electromagnetic force. No photons, no light. Also, no atoms - the electrons are attracted to protons through electromagnetism. And no kinetic energy either - it's electromagnetic. Which means no heat, no Brownian Motion, you get the idea. I mean, what's left without electromagnetic force? The weak force, the strong force, gravity. Uhm... That's not a lot to work with. I can't even think what would happen to the world - matter is held together by the electromagnetic force. Would everything just collapse into a single point?

[/ QUOTE ]

Is it even possible to isolate a region of space from EM? I didn't think of the instanteous effects, just the magnetic repercussions. Even a polar flipflop is chaotic to the biosphere. Remove it altogether, I don't know. Maybe not a collapse, but a timelike static, steady state. Matter death without evaporation?

A wasteland frozen on every possible level, what of quantum effects... AFAIK, those aren't dependent on any of the forces, they are merely reactive to whatever elements.

What would function in a quantum vacuum?