The Earth phase, Terra phase, Terrestrial phase or phase of the Earth, is the shape of the directly sunlit portion of the Earth as viewed from the Moon (or elsewhere extraterrestrially). From the Moon, the Earth phases gradually and cyclically change over a period of about a month, as the orbital positions of the Moon around the Earth and of the Earth around the Sun shift.
Earth phase | the shape of the directly sunlit portion of the Earth as viewed from the Moon
Questions and Answers
Q: What is the Earth phase?
A: The Earth phase, also known as the Terra phase, Terrestrial phase or phase of the Earth, is the shape of the directly sunlit portion of the Earth as viewed from the Moon (or elsewhere extraterrestrially).
Q: How often does it change?
A: The Earth phases gradually and cyclically change over a period of about a month.
Q: What causes it to change?
A: The changes in the Earth phases are caused by shifts in orbital positions of both the Moon around the Earth and of the Earth around the Sun.
Q: From where can we view this phenomenon?
A: We can view this phenomenon from either from the Moon or from other extraterrestrial locations.
Q: Is there any other name for this phenomenon?
A: Yes, it is also referred to as Terra phase, Terrestrial phase or phase of the Earth.
Q: How long does it take for one cycle to complete?
A: One cycle takes approximately one month to complete.