On Other Celestial Bodies
The phenomenon of day and night is due to the rotation of a celestial body about its axis, creating the illusion of the sun rising and setting. Different bodies spin at very different rates, however. Some may spin much faster than Earth, while others spin extremely slowly, leading to very long days and nights. The planet Venus rotates once every 224.7 days – by far the slowest rotation period of any of the major planets. In contrast, the gas giant Jupiter's sidereal day is only 9 hours and 56 minutes. A planet may experience large temperature variations between day and night, such as Mercury, the planet closest to the sun. This is one consideration in terms of planetary habitability or the possibility of extraterrestrial life.
Read more about this topic: Night
Famous quotes containing the words celestial bodies, celestial and/or bodies:
“It would be well, perhaps, if we were to spend more of our days and nights without any obstruction between us and the celestial bodies.... Birds do not sing in caves, nor do doves cherish their innocence in dovecots.”
—Henry David Thoreau (1817–1862)
“I have always endeavored to acquire strict business habits; they are indispensable to every man. If your trade is with the Celestial Empire, then some small counting house on the coast, in some Salem harbor, will be fixture enough.”
—Henry David Thoreau (1817–1862)
“People stress the violence. That’s the smallest part of it. Football is brutal only from a distance. In the middle of it there’s a calm, a tranquility. The players accept pain. There’s a sense of order even at the end of a running play with bodies stewn everywhere. When the systems interlock, there’s a satisfaction to the game that can’t be duplicated. There’s a harmony.”
—Don Delillo (b. 1926)