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Old 08-02-2009, 01:43 AM
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The Lone Ranger The Lone Ranger is offline
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Default Re: Stupid Science Questions Thread

Yes, gravity waves travel at the speed of light. So if the Sun were to disappear right now, it would be about 8 minutes before we could possibly know about it, because no information can be propagated faster than the speed of light -- it would take about 8.5 minutes for the light leaving the Sun right now to reach us, and for the gravity waves as well.


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As an aside, a heated object normally cools in an exponential manner. That is, it initially cools quickly, but as its temperature falls, the rate at which it continues to lose heat decreases.

This is because energy often behaves as if it is flowing. The greater the temperature difference between two objects, the faster that heat flows from the warmer object to the cooler one. By the same token, as they approach the same temperature, the rate of heat exchange between the objects decreases dramatically.

That's why it would take only a few days for the Earth's surface to cool so much that life on land wouldn't be possible, but it would take literally millions of years to reach thermal equilibrium with its surroundings.

Here's what a typical cooling curve looks like:


Cheers,

Michael
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