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Mercury Fall 2007 Table of Contents

by Joel Marks

Everybody knows that Earth rotates 360 degrees each day, which is why the Sun comes back to the same place in the sky after 24 hours. Indeed, that is what makes a day a day. And everybody knows that Earth does this 365&1/4 times each year, which is why the Sun returns to the same place in the zodiac after 365&1/4 days. Indeed, that is what makes a year a year (although we round them out to three of 365 days followed by a leap year).

Yes, everybody knows these things, but "everybody" is wrong.

No, I am not suggesting that we return to the days of stationary Earth at the center of a cosmos that revolves around us. The point is rather that Earth turns more than most people think it does.

To understand what is going on, it helps, first, to realize that we live in a whirling universe: everything turns! Every star, every planet, every rock in space is spinning; moons revolve around planets, planets revolve around suns, suns revolve around galaxies. It’s a dizzying fact of existence.

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