If the Sun dissipated ?

[prohornblower]

For the science-minded...

How long would human life on Earth last/survive if the Sun was no longer? What about other forms of life? Flora? Fauna? Microorganisms?

Explain to this science-noob how you think the process of death would transpire. What order things would die...what/where would offer humans the best chance of survival...etc..

Thanks. [img]/images/graemlins/cool.gif[/img]

[m_the0ry]

I would wager that geothermal energy and fossil fuels could sustain a number of people (probably on the order of magnitude of millions) by growing food with artificial light. Obviously less developed countries would have mass extinction if they do not have a power grid that can deliver extremely large amounts of power for growing mass food under artificial light. Animals that were not pandered by the artificial energy (basically anything thats not a pig, cow or chicken) would die basically within a few months.

Life in general, however, would persist for probably a few million years after that. There is an entire ecosystem under the water that recieves no light based energy, which would be almost completely unaffected.

[speedfreek]

If the Sun dissipated, or was no longer there, the Earth would stop orbiting it and would carry on at a tangent to its original orbit. After 8 minutes or so, we would recieve no more light. With no Sun to warm us, the planet would soon freeze. Geothermal energy wouldn't be enough to keep us going.

Within a short time, all unprotected life would die. Maybe we could protect ourselves from the cold somehow, but before long the atmosphere itself would condense and freeze. In the end the surface temperature (of the frozen atmosphere) would drop to well below -230C.

[prohornblower]

The geothermal energy would not last long at all, IMO. Heat would radiate back out of the atmosphere at an alarming rate once the Sun expired.

Good point about deep sea life. But wouldn't the water get so cold so fast that most life even in the deep sea would perish?

[ChrisV]

Humans and other surface life would have no chance at all of surviving. It would not take long for the Earth to be completely covered in a layer of ice and frozen gases miles thick.

As another poster mentioned, the deep sea ecosystem would persist for some time. I have no idea how long it would take for geothermal energy to die down, but the core of the earth is a gigantic heat sink. It would have to be years at the very least.

[Ohgod]

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I have no idea how long it would take for geothermal energy to die down, but the core of the earth is a gigantic heat sink. It would have to be millions of years at the very least.

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FYP.

That doesn't mean we wouldn't all die and the surface wouldn't be covered in frozen gases miles thick within a few years, though.

[prohornblower]

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I have no idea how long it would take for geothermal energy to die down, but the core of the earth is a gigantic heat sink. It would have to be years at the very least.

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I don't think this is the case. Once the Sun were to die out, space would become unimaginably cold. Heat would rush from the Earth to space at an alarming rate. I'm thinking this process would take no longer than a month max. Probably more like under two weeks.

[DCopper04]

good question

[Ohgod]

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I have no idea how long it would take for geothermal energy to die down, but the core of the earth is a gigantic heat sink. It would have to be years at the very least.

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I don't think this is the case. Once the Sun were to die out, space would become unimaginably cold. Heat would rush from the Earth to space at an alarming rate. I'm thinking this process would take no longer than a month max. Probably more like under two weeks.

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It depends what you are talking about. If you are referring to the surface of the planet, yes. The atmosphere would freeze and we all die. If you're talking about the interior of the planet, not even close to right. The timescale for conduction in the lithosphere is of the order of 60 million years - the core would carry on merrily doing its thing for at least a few hundred million years before there would be any effect at all to 'turning the sun off', and even then I imagine the effect would be tiny. Remeber the temperature of the core is ~4000K - a change of 300K in the surface temperature would have little effect on the evolution of the interior.

[prohornblower]

Another thing to consider is thermal lag of the Sun. This is about a month to a month-and-a-half generally.

In other words, the Sun is at its extreme on the solstices (late Jun/Dec), but the Earth is warmest in late July-ish, and coldest in late January-ish.

So the troposphere is retaining about a month worth of sun heat at all times. This is when the Sun is continually pounding on it each day, though. If it went out, the surface of the Earth should lose almost all of its Sun heat due to radiation in just a week or two.

I'll admit, I'm not too knowledgable about the center of the Earth, or what it would be doing. If it were warm enough for millions of years, though, I don't see how civilization could utilize enough manpower in such a short time to create any kind of sustainable univeral dwelling down there.

I would love to watch a movie about this. And The Day After Tomorrow didn't cut it. lol.