|ESA Science & Technology||30-Jun-2005 10:40:48|
Last Update: 04 Jul 2003What are the constituents of Mercury's tenuous atmosphere (exosphere)?
Mercury has no stable atmosphere; the gaseous environment of the planet is best described as an exosphere, a medium so rarefied that the neutral atoms of its constituents never collide. Five elements - oxygen, hydrogen, neon, sodium and potassium - have been detected by Mariner 10 and by ground-based observations.
The atoms that make up the exosphere were forced out of Mercury's crust by impacting high-energy photons and ions from the Sun and by incoming micrometeorites. The study of the exosphere will therefore provide another clue to the chemical composition of the surface.
For further information please contact: SciTech.firstname.lastname@example.org