Fountain theory

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The dynamic fountain theory explains how dust floating above the surface of the moon can reach great heights. The theory was developed by Timothy J. Stubbs , Richard R. Vondrak and William M. Farrell from the Laboratory for Extraterrestrial Physics at Goddard Space Flight Center of NASA set up.

Although the moon has no atmosphere, there is a thin layer (~ 3 cm - 30 cm) of dust particles floating above the surface. The cause of this phenomenon lies in the electrostatic charging of the dust by sunlight and by electrically charged particles from the solar wind . In addition, a phenomenon called “lunar horizon glow” observed by astronauts led to the hypothesis that a possible “dusty atmosphere” of the moon could extend to greater heights. Against this background, the "Dynamic Fountain Model" provides the theoretical basis for a simulation that shows the conditions under which moon dust (particle size <1 µm) is repelled from the surface and reaches heights of ~ 100 km can only to sink back to the ground due to gravity . The term “fountain” is intended to evoke the idea of ​​an (American) drinking water fountain: The water arch from the crane appears static, but the water itself is in motion.

The NASA mission Lunar Atmosphere and Dust Environment Explorer (LADEE) from 2013, among other things, was supposed to investigate the "lunar glow of the horizon" on the basis of the dynamic fountain model, but could not find any evidence for a permanent dusty atmosphere of the moon. The optical phenomena observed by astronauts are now interpreted as zodiacal light caused by interplanetary dust particles in the inner solar system.

Web links

Individual evidence

  1. TJ Stubbs, RR Vondrak, WM Farrell: A DYNAMIC MODEL FOR FOUNTAIN LUNAR DUST; in: Lunar and Planetary Science XXXVI; 2005 - ( PDF; 280 kB ) (English)
  2. Timothy J. Stubbs, Richard R. Vondrak, William M. Farrell: A dynamic fountain model for dust in the lunar exosphere; 2005 - ( PDF; 3.2 MB ) (English)
  3. ^ NASA, Ames Research Center: What is LADEE, the Lunar Atmosphere and Dust Environment Explorer? , April 4, 2019 (English)
  4. NASA, Ames Research Center, Rick Elphic: LADEE Project Scientist Update: August 2015 , version from August 7, 2017 (English)