Premium Only Content
Moon Phase and Libration, 2022 South Up, NASA.
Lunar Reconnaissance Orbiter (LRO) has been in orbit around the Moon since the summer of 2009. Its laser altimeter (LOLA) and camera (LROC) are recording the rugged, airless lunar terrain in exceptional detail, making it possible to visualize the Moon with unprecedented fidelity. This is especially evident in the long shadows cast near the terminator, or day-night line. The pummeled, craggy landscape thrown into high relief at the terminator would be impossible to recreate in the computer without global terrain maps like those from LRO.
The Moon always keeps the same face to us, but not exactly the same face. Because of the tilt and shape of its orbit, we see the Moon from slightly different angles over the course of a month. When a month is compressed into 24 seconds, as it is in this animation, our changing view of the Moon makes it look like it's wobbling. This wobble is called libration.
The word comes from the Latin for "balance scale" (as does the name of the zodiac constellation Libra) and refers to the way such a scale tips up and down on alternating sides. The sub-Earth point gives the amount of libration in longitude and latitude. The sub-Earth point is also the apparent center of the Moon's disk and the location on the Moon where the Earth is directly overhead.
The Moon is subject to other motions as well. It appears to roll back and forth around the sub-Earth point. The roll angle is given by the position angle of the axis, which is the angle of the Moon's north pole relative to celestial north. The Moon also approaches and recedes from us, appearing to grow and shrink. The two extremes, called perigee (near) and apogee (far), differ by as much as 14%.
The most noticed monthly variation in the Moon's appearance is the cycle of phases, caused by the changing angle of the Sun as the Moon orbits the Earth. The cycle begins with the waxing (growing) crescent Moon visible in the west just after sunset. By first quarter, the Moon is high in the sky at sunset and sets around midnight. The full Moon rises at sunset and is high in the sky at midnight. The third quarter Moon is often surprisingly conspicuous in the daylit western sky long after sunrise.
#moon#space#nasa#viral#knowledge#huzaifa#views#trending#technology#
-
51:35
Dr Steve Turley
1 day ago $13.12 earnedROSEANNE BARR - Her Journey, TRUMP, and the MAGA GOLDEN AGE! [INTERVIEW]
28.3K47 -
57:38
The Tom Renz Show
5 hours agoMerry Christmas - The Tom Renz Show Christmas
60.4K10 -
2:59:10
Wendy Bell Radio
15 hours agoThe Bridge Too Far
136K215 -
1:03:45
Donald Trump Jr.
1 day agoHappy Festivus: Airing Our Grievances and Stopping The Swamp w/Sean Davis | TRIGGERED Ep.201
404K535 -
1:30:30
Game On!
18 hours ago $7.59 earnedTop 5 things you need to know for Sports Christmas!
63.9K5 -
1:58:10
Robert Gouveia
1 day agoMatt Gaetz REJECTS Report, Sues Committee; Luigi Fan Club Arrives; Biden Commutes; Festivus Waste
288K227 -
1:31:40
Adam Does Movies
1 day ago $15.83 earnedThe Best & Worst Christmas Movies! - LIVE!
112K8 -
58:10
Kimberly Guilfoyle
1 day agoAmerica is Back & The Future is Bright: A Year in Review | Ep. 183
200K76 -
3:03:27
vivafrei
1 day agoEp. 242: Barnes is BACK AGAIN! Trump, Fani, J6, RFK, Chip Roy, USS Liberty AND MORE! Viva & Barnes
270K261 -
2:05:48
2 MIKES LIVE
11 hours agoTHE MIKE SCHWARTZ SHOW with DR. MICHAEL J SCHWARTZ 12-24-2024
43.1K5