>An atomic clock can be very accurate, but would be meaningless to us unless it was in sync with our solar system, which itself is a poor clock, because the movements of the planets could be speeding up or down and not at all consistent over very long periods of time.
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If my understanding is correct, the method to determine sidereal [sic?] is based on observations of Jupiter's moons. If all the clocks stop working, we would read Jupiters moons, and use Galaleo's tables to convert to "earthtime".

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There is evidence of ice ages contrasted with periods of more moderate temperate over earths billions of years history, which would suggest that the earth may not rotate around the sun at a constant distance.
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It has also been suggested that as our solar system orbits the galactic core, it passes through the "dust" of the spiral arms, thus reducing the energy that reaches us from the sun. Impacts may also play a part in ice ages. The period of history known as the "dark ages", also produced a "mini" ice age. The skys in Europe were sunless for a year or more! The suspected culprit is a comet impact!
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What a different concept of time I would have, if I existed in a pure energy state, like electricity or some kind of pure light. In such a state I could consume a lot of space, because my speed would allow me to partically be everywhere at once.
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It turns out that quanta, like nuetrinos, decay from existance. A nuetrino, because it is relativistic, does not experience time change, but it does die!

One cosemologist (PBS COSMOS and "First Contact" - Carl Sagen?), asked and answered a question:

"Want to know what it's like to be inside a blackhole? Just look around!"

It seems no matter how simply the world is explained - it remains magic to me:)

>Regards,
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>LelandJ