2007-04-20 05:56:36 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
The mass of the moon is not distributed evenly; the dark maria are basalt which is heavier than the light-coloured rocks that make up most of the lunar surface -- including pretty much the entire other side.
This additional mass has, over billions of years, tidally locked the Moon so the heaviest part of the surface is pointed at Earth. Thus, the lunar "day" and "year" are almost the same (the "year" is ever so slightly longer because the Earth moves in a curved orbit around the Sun).
That being said, it's interesting to note that while the lunar day and year match up, the Moon is not always pointing the same way towards Earth. It rotational speed is constant, but since its orbit is not circular its ORBITAL speed increases and decreases. This makes the moon "wobble" slightly from side to side, and allows 56% of the Moon's surface to be seen from Earth, instead of 50%.
2007-04-20 06:34:01 · answer #1 · answered by poorcocoboiboi 6 · 0⤊ 0⤋
a year by who's definition? I would say that a day on the moon is a month on Earth and 12 days on the moon will be a year.
2007-04-20 22:19:31 · answer #2 · answered by paulbritmolly 4 · 0⤊ 0⤋
They aren't A day is 29 Earth days or so. A Year is about an earth year, depending on where the moon is in it's orbit around earth.
2007-04-20 18:54:01 · answer #3 · answered by Nomadd 7 · 0⤊ 0⤋
Because the moon doesn't spin on a axis like the earth and other planets do. So technically a day is also a year for the moon.
2007-04-20 12:59:48 · answer #4 · answered by Anonymous · 0⤊ 1⤋
They are not. The lunar month and day are approximately the same, because the moon is tidally locked to the earth (the same side always faces us).
Thus, in its month long orbit around the earth, the moon experiences only one slow sunrise.
2007-04-20 12:59:09 · answer #5 · answered by Anonymous · 0⤊ 1⤋
They are the same because the period of rotation is the same as the period of rotation.
In other words, it takes the moon the same amount of time to turn once around is axis (day) than to rotate around the earth once (year).
2007-04-20 12:59:33 · answer #6 · answered by rfmarves 2 · 0⤊ 0⤋
Actually, they aren't, if you use meaningful definitions.
A "day" is the length of time it takes a body to rotate once on its axis. For the moon, that is approx. 29 days.
A "year" is the length of time it takes a body to orbit once around the sun. For the moon, which is bound gravitationally to the Earth, that is 365.25 days, approx.
2007-04-20 15:22:35 · answer #7 · answered by JIMBO 4 · 0⤊ 0⤋
because the moon does one revolution per one rotation. that's also why we always see the same side of the moon.
2007-04-20 13:01:42 · answer #8 · answered by Anonymous · 0⤊ 0⤋
WRONG! "Day" and "month" are almost the same on the moon.
2007-04-20 13:22:02 · answer #9 · answered by Surveyor 5 · 0⤊ 0⤋