Jupiter’s atmosphere has much more water than we expected

Hyperaxion Feb 22, 2020

Measurements made by Juno spacecraft contradict the theory formulated by astronomers 25 years ago. For scientists, this proves that the solar system’s gas giant is still a mystery.

Theories about Jupiter’s atmosphere were wrong, according to a study published by NASA astronomers in Nature Astronomy. Thanks to data recently sent by the Juno spacecraft, we found that the atmosphere of the largest planet in the Solar System is made up of at least 0.25% water – a significantly larger amount than previously believed.

Juno was launched in 2011, arrived on the planet in 2016 and is scheduled to work until the end of 2021. According to experts, this is the first time that we have obtained information about water existing on Jupiter since 1995, when the Galileo spacecraft, which was orbiting the planet, has been disabled.

An intriguing surprise

For 25 years, scientists believed that there was more water in the Sun’s atmosphere than in Jupiter’s atmosphere. The new measurements, however, show that the reality is just the opposite: Jupiter has three times more water in its atmosphere than our star.

A limited data sample

For astronomers, the measurement error probably occurred because Galileo tested and sent data for a specific region of Jupiter’s atmosphere. It seems that the atmospheric composition of the planet is very agitated and inhomogeneous – which was also revealed by information sent by Juno.

Jupiter's atmosphere has much more water than we expected
Jupiter’s atmosphere has much more water than we expected. (Source: NASA).

“When we thought we had already discovered things, Jupiter reminds us how much we still need to learn,” said Scott Bolton, one of the researchers, in a statement. “Juno’s surprising discovery that the atmosphere is not very heterogeneous, even in the region far below the top of the clouds, is a puzzle that we are still trying to figure out. No one would imagine that water could be so variable across the planet.”

A lot more is to come

Now the team is excited about the discoveries to come, as the article was the result of only the first of eight missions scheduled to investigate the Jupiterian atmosphere. The astronomers’ idea is to study the equatorial region of Jupiter, but also to explore the northernmost latitudes of the planet.

Every scientific flyby is a discovery event,” said Bolton. “With Jupiter, there is always something new. Juno taught us an important lesson: we need to approach a planet to test our theories.”


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