Lagrange point

English

Lagrange points (green), primary central object (yellow) and secondary orbiting object (blue)

Alternative forms

• Lagrangian point

Etymology

60-degree separation of L4 and L5 Lagrange points

Named after Joseph Louis Lagrange, who discovered the points L₄ and L₅, building on earlier work by Leonhard Euler, and in 1772 published an essay on the three-body problem.

Noun

Lagrange point (plural Lagrange points)

1. (astrophysics, orbital mechanics) A point in an orbital configuration of a two-body system where a small object affected only by gravity can theoretically be stationary relative to the two larger objects.

   Mathematically, the Lagrange points represent solutions to a restricted form of the three body problem in which the mass of one object is assumed negligible compared to that of the two principal bodies—as, for example, an artificial satellite and the Earth-Moon system.

   • 2008, David Schrunk, Burton Sharpe, Bonnie L. Cooper, Madhu Thangavelu, The Moon: Resources, Future Development and Settlement, Springer, Praxis Publishing, page 57:

     Lagrange points are significant for lunar development in that raw materials, such as near-Earth objects (NEOs) can be safely stored at L-4 and L-5 prior to mining and processing.

   • 2013 July 28, Megan Gannon, “Spacecraft Sees Giant 'Hole' In the Sun”, in news.yahoo.com‎^[1], retrieved 2013-07-29:

     The $1.27-billion (1 billion euros) SOHO satellite was launched in 1995 and is flying a joint mission between NASA and the European Space Agency (ESA). It watches solar activity from an orbit about the Lagrange Point 1, a gravitationally stable spot between Earth and the sun that is about 932,000 miles (1.5 million kilometers) from our planet.

   • 2016, Francis Lyall, Paul B. Larsen, Space Law‎^[2], Taylor & Francis (Routledge), page 247:

     For science several of the Lagrange points are important. The question of access to Lagrange points or GSO slots emerges as these become congested.

Synonyms

• (astrophysics): L-point

Hypernyms

• (astrophysics): libration point

Hyponyms

• (astrophysics): Trojan point

Derived terms

• (astrophysics): Lagrangian, Lagrangian asteroid, Lagrangian moon, Lagrangian planet

Related terms

• (astrophysics): L1, L2, L3, L4, L5

Translations

point in an orbital configuration

• Arabic: نُقْطَة لَاغْرَانْج f (nuqṭat laḡranj)
• Chinese:

  Mandarin: 拉格朗日點／拉格朗日点 (zh) (Lāgélǎngrì diǎn)

• French: point de Lagrange (fr) m
• German: Lagrange-Punkt m
• Italian: punto di Lagrange m
• Japanese: ラグランジュ点 (Raguranju-ten)
• Korean: 라그랑주점 (Rageurangju-jeom)
• Persian: نقطه لاگرانژی (noqte-ye lâgrânži)
• Russian: то́чка Лагра́нжа f (tóčka Lagránža)
• Spanish: punto de Lagrange m
• Swedish: Lagrangepunkt c
• Vietnamese: điểm Lagrange

See also

• (astrophysics): barycenter