Juno spacecraft unlocks mysteries of Jupiter’s Great Red Spot

Jupiter’s iconic Great Red Spot (GRS) extends deeper into the gas giant than previously expected, Nasa researchers have said, after studying new data from the Juno spacecraft.

Jupiter's famed 16,000km-wide tempest has been churning in the planet’s atmosphere for several centuries and is big enough that it could swallow the Earth whole.

Juno was launched in 2011 with the explicit mission of closely studying Jupiter and its moons. It finally reached the planet in 2016 after a gruelling five-year, 1.4 billion-mile trip.

Its findings reveal new insights into Jovian (Jupiter) meteorology and its links to the planet’s deeper interior.

While it has long been known that large storms and bands of rotating winds are common in Jupiter’s atmosphere, it’s unclear whether these storms are confined to the uppermost parts of the planet’s atmosphere or extend deeper into the planet.

In a pair of studies, researchers used microwave and gravity measurements, respectively, from the Juno spacecraft to gain more insight into Jupiter’s atmospheric vortices, including the GRS.

Juno’s Microwave Radiometer (MWR) instrument was used to investigate the vertical structure of the GRS as well as two other storms. It was found that they extend below the altitude at which water and ammonia are expected to condense - or the planet’s cloud level - and this is particularly true for the GRS.

The researchers believe that this suggests the presence of small-scale dynamic processes, such as precipitation and downdrafts, at much deeper levels than previously expected, which may indicate a connection between Jupiter’s interior and deep atmosphere.

They examined the gravity signature of the GRS and further constrained its depth. Within the gravity measurements taken as Juno flew above, they detected fluctuations in the planet’s gravitational field caused by the storm.

It was found that, although the GRS is deeply rooted within the atmosphere, it’s far shallower than the surrounding zonal jets that power the GRS, which extend much deeper.

According to the findings, the depth of the GRS is no more than 500km deep while the surrounding jets extend to depths approaching 3,000km.

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