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Credit & Copyright: Data: Lunar Reconnaissance Orbiter
;
Animation:
NASA's
Scientific Visualization Studio;
Music: Brandenburg Concerto No4-1 BWV1049 (Johann Sebastian Bach), by Kevin MacLeod via Incompetech
Explanation:
What will the Moon phase be on your birthday this year?
It is
hard
to predict because the
Moon's appearance changes nightly.
As the
Moon orbits the
Earth,
the half illuminated by the
Sun
first becomes increasingly visible, then decreasingly visible.
The featured video animates images taken by NASA's Moon-orbiting
Lunar Reconnaissance Orbiter to show all
12 lunations that appear this year, 2021.
A single
lunation
describes one full cycle of our Moon, including all of its
phases.
A full
lunation takes about 29.5 days, just under a month
(moon-th).
As each
lunation progresses, sunlight reflects from the
Moon at different angles, and so
illuminates different features differently.
During all of this, of course,
the Moon
always keeps the same face toward the
Earth.
What is less apparent night-to-night is that
the Moon's apparent size changes slightly,
and that a slight wobble called a
libration occurs as the
Moon progresses along its elliptical orbit.
Music: Brandenburg Concerto No4-1 BWV1049 (Johann Sebastian Bach), by Kevin MacLeod via Incompetech
APOD online webinar January 12:
Free registration,
hosted by Amateur Astronomers Association of New York.
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: Moon
Publications with words: Moon
See also: