Earth phase
 Earthrise by Apollo 8 astronaut William Anders, December 1968. Earth at gibbous phase as seen from the Moon. | |
The Earth phase, Terra phase, terrestrial phase, or phase of Earth, is the shape of the directly sunlit portion of Earth as viewed from the Moon (or elsewhere extraterrestrially). From the Moon, the Earth phases gradually and cyclically change over the period of a synodic month (about 29.53 days), as the orbital positions of the Moon around Earth and of Earth around the Sun shift.[1][2][3][4][5][6]
Overview
Among the most prominent features of the Moon's sky is Earth. Earth's
As a result of the Moon's
If the Moon's rotation were purely synchronous, Earth would not have any noticeable movement in the Moon's sky. However, due to the Moon's libration, Earth does perform a slow and complex wobbling movement. Once a month, as seen from the Moon, Earth traces out an approximate oval 18° in diameter. The exact shape and orientation of this oval depend on one's location on the Moon. As a result, near the boundary of the near and far sides of the Moon, Earth is sometimes below the horizon and sometimes above it.
To be aware, although genuine photographs of the Earth viewed from the Moon exist, many from NASA, some photographs shared on social media, that are purported to be the Earth viewed from the Moon, may not be real.[7]
Phases of the Earth
- Earth phases
-
Full -
Gibbous -
Low-illumination gibbous -
Very low-illumination gibbous -
Half -
High-illumination crescent -
Crescent -
Low-illumination crescent
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See also
- Earthrise
- Extraterrestrial sky
- List of first images of Earth from space
- List of notable images of Earth from space
- Lunar phase
- Overview effect
- Pale Blue Dot
- Pale Orange Dot (Early Earth)
- Planetary phase
- The Blue Marble
- The Day the Earth Smiled
References
- ^ Gannon, Megan (30 June 2019). "If You're On the Moon, Does the Earth Appear to Go Through Phases?". Live Science. Retrieved 30 June 2019.
- ^ Staff (13 March 2013). "The Phases of Earth". Futurism.com. Retrieved 30 June 2019.
- ^ Staff (21 June 2008). "Changing Earth phases, seen from the moon". Earth & Sky. Retrieved 30 June 2019.
- ^ King, Bob (17 October 2018). "Observing Earth from the Moon". Sky & Telescope. Retrieved 30 June 2019.
- ^ Staff (15 July 1999). "If you are on the moon, does the Earth have phases similar to moon phases? Would they be the same or reversed?". University of California, Santa Barbara. Retrieved 1 July 2019.
- ^ Cain, Fraser (13 October 2014). "What Does Earth Look Like From the Moon?". Universe Today. Retrieved 1 July 2019.
- ^ Evon, Dan (15 July 2019). "Is This a Real Photo of the Earth from the Moon? - Genuine photographs showing the Earth from the moon exist, many from NASA". Snopes. Retrieved 17 July 2019.