![]() The Moon's rotation is locked rotation, meaning that its rotational period is the same as its orbital period. That period (called a tidal day) is, on average, about 24 hours, 50 minutes. Beause the Moon's real orbital motion eastward is in the opposite direction to its apparent westward motion, but much slower, it has the effect of making the period from one upper transit of the Moon to the next longer than 24 hours. ![]() This westward motion is not real motion it is apparent motion - an optical illusion caused by our planet's rotation on its axis from west to east. At moonrise it appears above our eastern horizon, at moonset it descends below our western horizon and halfway between the two it reaches upper transit when it crosses our meridian heading westward. If you were viewing the solar system from a point high above the Earth's north pole, those motions would appear anti-clockwise from your point of view.ģ) Additionally, to us on Earth, the Moon appears to continuously move across our sky from east to west. The direction of its orbital motion is the same as the direction of its rotation and that is also the direction of the Earth's rotational and orbital motions. If you make a fist of your right hand with the thumb pointing upward, your fist represents the body, your raised thumb represents the direction the north pole points toward and your curled fingers point in the direction of the body's spin.Ģ) The Moon also revolves around the Earth, meaning it orbits or circles the Earth. The right-hand rule defines the relationship between the direction that we call "north" and the direction of the body's spin. The Earth's and the Moon's rotation both obey the "right-hand rule," which is followed by most of the major bodies of our solar system (the planets and their Moons). The Moon's north and south poles point toward (approximately) the same directions in space as the Earth's north and south poles, and, like the Earth, the Moon rotates from west to east. The Moon has two real motions and one apparent motion:ġ) It rotates (spins) around its own axis, which is the line through the centre of the Moon from its north pole to its south pole. THE MOON'S CYCLES AND ASSOCIATED TERMINOLOGY
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |