Exploring Jupiter's enigma: The quest to unravel the Great Blue Spot
– It's a mystery. We don't know why this place is such an anomaly – said Yohau Kaspi from the Weizmann Institute of Science in Israel and a researcher of NASA's Juno mission during a conversation with Space portal.
This anomaly near Jupiter's equator is related to the planet's magnetic field activity. The Great Blue Spot, as it is referred to, is not actually blue – as the name suggests. The name comes from the colour scale used to create maps of Jupiter's magnetic field.
To closely examine the anomaly, which is an exceptionally intense magnetic field (being up to 20 times stronger than Earth's), scientists have studied so-called atmospheric jets, which the Juno probe has been observing over the past years. These are strong and weak discharges that occur in Jupiter's atmosphere. The new discovery suggests that, similar to ocean waves which change their speed during movement, there could be similar phenomena occurring deep within Jupiter's core, potentially powering the observed surface magnetic field.
The newly discovered jet by scientists can drift in the area of the Great Blue Spot (at a depth of even 3 km, or nearly 2 miles), however, Jupiter's magnetic field suppresses the jet's "journey" at this deep point. In this location, it moves considerably slower (a few centimetres per second) compared to the jets on the surface.
– The discovery is a very marginal measurement – explained Kaspi. In his opinion, the result should be treated as preliminary, which needs to be thoroughly examined since scientists lack more concrete knowledge that would allow them to study the behaviour of jets near the Great Blue Spot.
For the moment, scientists suspect that in the mentioned spot on Jupiter there are periodic changes in the magnetic field strength, which are associated with the convective flow deep beneath the planet's surface. These changes are believed to occur every four years, but the problem is that data collected from Jupiter that allow the determination of the periodicity of the phenomenon have been recorded for five years. As a result, Kaspi emphasises that in light of this, "nothing can be said about the four-year period". Further data collected by Juno will help science understand how Jupiter's complex magnetic field is driven.
