| Neon is actually abundant on a universal scale: the fifth most abundant chemical element in the universe by mass, after hydrogen, helium, oxygen, and carbon. Its relative rarity on Earth, like that of helium, is due to its relative lightness and chemical inertness, both properties
keeping it from being trapped in the condensing gas and dust clouds of the formation of smaller and warmer solid planets like
Earth. Mass abundance in the universe is about 1 part in 750 and in the Sun and presumably in the proto-solar system nebula,
about 1 part in 600. The Galileo spacecraft atmospheric entry probe found that even in the upper atmosphere of Jupiter, neon
is reduced by about a factor of 10, to 1 part in 6,000 by mass. This may indicate that even the ice-planetesmals which brought
neon into Jupiter from the outer solar system, formed in a region which was too warm for them to have kept their neon (abundances
of heavier inert gases on Jupiter are several times that found in the Sun).
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Occurrence