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)
“The stillness was intense and almost conscious, as if it were a natural Sabbath, and we fancied that the morning was the evening of a celestial day.”
—Henry David Thoreau (1817–1862)
“At this very moment,... the most frightful horrors are taking place in every corner of the world. People are being crushed, slashed, disembowelled, mangled; their dead bodies rot and their eyes decay with the rest. Screams of pain and fear go pulsing through the air at the rate of eleven hundred feet per second. After travelling for three seconds they are perfectly inaudible. These are distressing facts; but do we enjoy life any the less because of them? Most certainly we do not.”
—Aldous Huxley (1894–1963)