The Origin of Jupiter's Great Red Spot

TL;DR

This paper investigates the origins and formation mechanisms of Jupiter's Great Red Spot, using historical observations and numerical simulations to propose it formed from flow disturbances between Jovian jets.

Contribution

It introduces new insights into the GRS's formation, ruling out vortex merging and superstorm scenarios, and suggests a flow disturbance origin based on historical and simulation data.

Findings

Historical observations show the 'Permanent Spot' is unlikely the GRS.

Simulations rule out vortex merging and superstorm formation.

The GRS likely formed from flow disturbances between Jovian jets.

Abstract

Jupiter's Grat Red Spot (GRS) is the largest and longest-lived vortex of all solar system planets but its lifetime is debated and its formation mechanism remains hidden. G. D. Cassini discovered in 1665 the presence of a dark oval at the GRS latitude, known as the "Permanent Spot" (PS) that was observed until 1713. We show from historical observations of its size evolution and motions that PS is unlikely to correspond to the current GRS, that was first observed in 1831. New numerical simulations rule out that the GRS formed by the merging of vortices or by a superstorm, but most likely formed from a flow disturbance between the two opposed Jovian zonal jets north and south of it. If so, the aearly GRS should have had a low tangential velocity so that its rotation velocity has increased over time as it shrunk.