perigee

From French périgée via Latin perigeum, perigaeum, ultimately from Ancient Greek περί (perí, “near”) + γῆ (gê, “Earth”).

• (UK) IPA^(key): /ˈpɛɹɪdʒiː/
• (US) IPA^(key): /ˈpɛɹədʒi/

perigee (plural perigees)

1. (astronomy) The point, in an orbit about the Earth, that is closest to the Earth: the periapsis of an Earth orbiter.
   • 2014 September 7, Natalie Angier, “The Moon comes around again [print version: Revisiting a moon that still has secrets to reveal: Supermoon revives interest in its violent origins and hidden face, International New York Times, 10 September 2014, p. 8]”, in The New York Times‎:

     As the moon wheels around Earth every 28 days and shows us a progressively greater and then stingier slice of its sun-lightened face, the distance between the moon and Earth changes, too. At the nearest point along its egg-shaped orbit, its perigee, the moon may be 26,000 miles closer to us than it is at its far point.

2. (astronomy, more generally) The point, in an orbit about any planet, that is closest to the planet: the periapsis of any satellite.
   • 1995, John H. Rogers, The Giant Planet Jupiter, Cambridge University Press, ISBN 978-0-521-41008-3, page 335:

     Conjunctions of I and II [Io and Europa] occur when they are near perigee and apogee respectively; conjunctions of II and III [Europa and Ganymede] occur when II [Europa] is near perigee.

   • 2002, Serge Brunier, Solar System Voyage, Cambridge University Press, ISBN 978-0-521-80724-1, page 36:

     The resolution of the images obtained by this American probe [Messenger] will depend on its altitude [above Mercury] at any one time: about ten meters at perigee (200km altitude), but only one 1 km at apogee (15000km).

   • 2010, Ruth Walker and Mary M. Shaffrey et al., Exploring Space: The High Frontier, Jones & Bartlett Learning, ISBN 978-0-7637-8961-9, page 129:

     [Nereid’s] apogee—farthest point from Neptune—is five times the distance of its perigee—its closest point.

3. (possibly archaic outside astrology) The point, in any trajectory of an object in space, where it is closest to the Earth.

• apogee

• proxigee

• perigee moon

• see periapsis

• periapsis, periastron, perihelion