Science For All

Will Jupiter’s Great Red Spot disappear?

A new Hubble Space Telescope view of the planet Jupiter, taken June 27, 2019, and part of yearly study called the Outer Planets Atmospheres Legacy program (OPAL), is shown in this composite photo released August 8, 2019. NASA/ESA/A. Simon/M.H.Wong/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY TPX IMAGES OF THE DAY | Photo Credit: HANDOUT

Jupiter’s iconic great red spot is the biggest storm in the Solar System.

The spot is so big that an entire earth could fit inside it and still have some space left. It is a large anticyclonic vortex — with winds reaching speeds of 450 km/h around its centre — with two parts to it: a reddish inner oval and a paler outer surrounding band called the hollow.

The great red spot is in effect a high-pressure region in Jupiter’s atmosphere, much like a big hurricane on the earth — but with some key differences. Unlike terrestrial hurricanes, which derive their energy from the warm waters of the oceans below, the great red spot is powered by the interplay of Jupiter’s internal heat with its tempestuous atmosphere.

While storms on the earth can drift up-down and sideways through the earth’s atmosphere, Jupiter’s storms are restricted to the latitude in which they form. In exchange, the storms last for a long period of time. And this gave many astronomers the impression that the great red spot is a permanent feature of the gas giant.

Giovanni Cassini possibly observed the spot first, in 1665. He described seeing a dark, oval feature he called the ‘permanent spot’. He and others reported seeing this feature intermittently until the early 18th century, after which it vanished from records for more than a century.

The great red spot in its current form was first clearly identified in 1831 by an amateur German astronomer named Samuel Schwabe, and it has been regularly observed since.

That is, the current great red spot is almost 200 years old.

Recent studies have found it has been shrinking since the 2010s, however. It may once have been so large as to fit three earths within itself.

After analysing the flow of atmospheric gases on Jupiter, scientists recently proposed three possible ways in which the spot could’ve been created: (i) The spot formed with the birth of a very ‘superstorm’, similar to those astronomers have sometimes found on Saturn. (ii) The spot formed when smaller vortices produced by wind shear merged together. (While numerical simulations support this idea, the vortices end up differing in shape and dynamics from the current spot.) (iii) A known instability in Jupiter’s winds produced an elongated cell that eventually enclosed and trapped the winds, forming a proto-spot. The third hypothesis is the most promising.

Over time, the proto-spot would have shrunk into a compact, rapidly rotating storm becoming the great red spot we see today. Models run on supercomputers have shown that such elongated cells can be stable while rotating around the spot at the speeds scientists have found today.

Given that it’s shrinking, scientists have said the great red spot could disappear one day, just as Cassini’s permanent spot vanished, leaving behind a spotless Jupiter.

From the Science pages

35 papers of a scientist from CSIR’s Indian Institute of Toxicology Research retracted

Scientists have confirmed a cave on the moon that could be used to shelter future explorers

As thoughts become digitised, who will protect our neurorights?

Scientists find how the same ear senses murmurs and listens to screaming music

Question Corner

What is the maximum heart rate of male noctule bats? Find out more.

Flora and fauna

Searching for LUCA, the first life-form from which all other life descended

World’s rarest whale may have washed up on New Zealand beach

Scientists found a bacteria tricked a wasp to get rid of its males

Snakes on a plate: pythons touted as protein alternative