Peak of eternal light

A peak of eternal light (PEL) is a hypothetical point on the surface of an astronomical body that is always in sunlight. Such a peak must have high latitude, high elevation, and be on a body with very small axial tilt. The existence of such peaks was first postulated by Beer and Mädler in 1837. The pair said about the lunar polar mountains: "...many of these peaks have (with the exception of eclipses caused by the Earth) eternal sunshine".[1] These polar peaks were later mentioned by Camille Flammarion in 1879, who speculated that there may exist pics de lumière éternelle at the poles of the Moon.[2] PELs would be advantageous for space exploration and colonization due to the ability of an electrical device located there to receive solar power regardless of the time of day or day of the year, and the relatively stable temperature range.

Detailed lunar topography collected by the Lunar Reconnaissance Orbiter (LRO) suggests that no points on the Moon receive perpetual light during both the winter and summer. However, there are points on crater rims which have very extended periods of sunlight.[3][4]

  1. ^ Beer, Wilhelm, and Mädler, Johann Heinrich (1837). Der Mond nach seinen kosmischen und individuellen Verhältissen oder allgemeine vergleichende Selenographie. Berlin, Simon Schropp and Co. (in German).
  2. ^ Flammarion, Camille. Astronomie Populaire, description générale du ciel. Paris, 1879. (in French).
  3. ^ Speyerer, Emerson J., and Robinson, Mark S. (2013). "Persistently illuminated regions at the lunar poles: Ideal sites for future exploration", Icarus, 222, No. 1, January, pp. 122–136.
  4. ^ Gläser, P., Oberst, J., Neumann, G. A., Mazarico, E., Speyerer, E. J., Robinson, M. S. (2017). "Illumination conditions at the lunar poles: Implications for future exploration", Planetary and Space Science, vol. 162, p. 170–178.