libration

American  

[lahy-brey-shuhn] / laɪˈbreɪ ʃən /

noun

Astronomy.

1. a real or apparent oscillatory motion, especially of the moon.

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libration British  

/ laɪˈbreɪʃən /

noun

1. the act or an instance of oscillating

2. a real or apparent oscillation of the moon enabling approximately 59 per cent of the surface to be visible from the earth over a period of time

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Other Word Forms

• librational adjective

Etymology

Origin of libration

1595–1605; < Latin lībrātiōn- (stem of lībrātiō ) a balancing. See librate, -ion

Example Sentences

Such libration could be explained in one of two ways: either Mimas had an extremely elongated core, shaped like a flattened football; or it had a global ocean below its surface.

From National Geographic • Feb. 7, 2024

A new paper by the same team, however, published today in Nature, closely studied how the libration changes the orbit of Mimas—and establishes that the moon indeed has a subsurface ocean.

From National Geographic • Feb. 7, 2024

Using documentary evidence in the Ansel Adams Archive and lunar libration, a phenomenon that “affects the visibility of lunar surface features,” according to Dr. Olson, they narrowed down the possibilities.

From New York Times • Mar. 13, 2023

At the Princeton gathering, O'Neill and others discussed the establishment of the first colony at a libration point called L5, which lies in the moon's orbit at a spot equidistant from earth and moon.

From Time Magazine Archive

They are called libration points, from the Latin word for balance, so we could properly name our new country Libra.

From "Flying to the Moon: An Astronaut's Story" by Michael Collins