Mercury

I'm reading Dava Sobel's The Planets:

"Indeed Mercury's proximity to the Sun dominates every aspect of the planet's existence - not just its tantivy progress through space, which is all that can be easily gleaned from Earth, but also its internal conflict, its heat, heaviness and the catastrophic history that left it so small (only one third Earth's width).

The pull of the nearby Sun rushes Mercury around its orbit at an average velocity of thirty miles per second. At that rate, almost double the Earth's pace, Mercury only takes 88 Earth days to complete its orbital journey. The same Procrustean gravity that accelerates Mercury's revolution, however, brakes the planet's rotation about its own axis. Because the planet forges ahead so much faster than it spins, any given locale waits half a Mercurian year (about six Earth weeks) after sunup for the full light of high noon. Dusk finally falls at year's end. And once the long night commences, another Mercurian year must pass before the Sun rises again. Thus, the years hurry by, while the days drag on forever.

Mercury most likely spun faster on its axis when the Solar System was young. Then, each of its days might have numbered as few as eight hours, and even a quick Mercurian year could have contained hundreds such. But the tides raised by the Sun in the planet's molten middle gradually damped Mercury's rotation down to its present slow gait."

Finally - a writer who can mix the poetry with the science!