libration

English

WOTD – 14 August 2010

The libration of the Moon over a single lunar month.

Etymology

From Latin lībrātiō (“a hurling, swinging”), from lībrō (“poise, cause to swing”).

Pronunciation

• (UK, US) IPA^(key): /laɪˈbɹeɪ.ʃən/

• Audio (US):

  (file)

• Rhymes: -eɪʃən

Noun

libration (countable and uncountable, plural librations)

1. The act of librating.
2. (astronomy) The apparent wobble or variation in the visible side of the Moon that permanently faces the Earth, allowing observers on Earth to see, over a period of time, slightly more than half of the lunar surface.
3. (by extension) A similar rotational or orbital characteristic of some other celestial body.
4. (dynamics) The oscillation of an angle about a stable equilibrium point.
5. (chemistry) A vibrational degree of freedom whereby a group of atoms partly rotates back and forth, similar to the Moon's motion.

Derived terms

• libration point

 

Related terms

• librate

 

Translations

act of libration

• Afrikaans: librasie (af)
• Armenian: ճոճում (hy) (čočum), երերում (hy) (ererum), տատանում (hy) (tatanum)
• Finnish: huojunta (fi)
• German: Ausschwingen n, Pendeln (de) n
• Russian: качание (ru) (kačanije)

astronomy: apparent wobble of the moon

• Armenian: լիբրացիա (hy) (libracʻia), ճոճք (hy) (čočkʻ)
• Finnish: huojunta (fi), libraatio
• German: Libration (de) f
• Icelandic: tunglvik n
• Japanese: 秤動 (ja) (ひょうどう, hyōdō)
• Korean: 칭동 (chingdong)
• Russian: либра́ция (ru) (librácija)

astronomy: similar characteristic of another celesial object

• Armenian: լիբրացիա (hy) (libracʻia), ճոճք (hy) (čočkʻ)
• Finnish: huojunta (fi), libraatio
• Korean: 칭동 (chingdong)
• Russian: либра́ция (ru) (librácija)

See also

• nutation

 

French

Pronunciation

• Audio:

  (file)

Noun

libration f (plural librations)

1. libration

Derived terms

• point de libration

Further reading

• “libration”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.