NASA’s Juno mission has provided its first science results on the amount of water in Jupiter’s atmosphere.

Published recently in the journal Nature Astronomy, the Juno results estimate that at the equator, water makes up about 0.25% of the molecules in Jupiter’s atmosphere—almost three times that of the Sun. These are also the first findings on the gas giant’s abundance of water since the agency’s 1995 Galileo mission suggested Jupiter might be extremely dry compared to the Sun (the comparison is based not on liquid water but on the presence of its components, oxygen and hydrogen, present in the Sun).

An accurate estimate of the total amount of water in Jupiter’s atmosphere has been on the wish lists of planetary scientists for decades: The figure in the gas giant represents a critical missing piece to the puzzle of our solar system’s formation. Jupiter was likely the first planet to form, and it contains most of the gas and dust that wasn’t incorporated into the Sun.

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