Classical Astronomers Observed a Different Great Red Spot on Jupiter

In 1665, astronomer Giovanni Domenico Cassini observed a monolithic tempest raging connected Jupiter. It became known arsenic the Great Red Spot, a swirling oval of clouds that’s astir doubly arsenic wide arsenic Earth. New research, however, suggests that the red-hued diagnostic spotted by Cassini is not the aforesaid tempest we spot today.

Using humanities observations of Jupiter from the 17th century, a squad of scientists recovered that the Great Red Spot has apt persisted for a specified 190 years arsenic opposed to 300 years of swirling winds. In a paper published successful the Geophysical Research Letters, the researchers reason that the swirling tempest observed by Cassini is present gone, but that a caller 1 was calved successful its spot years later.

After discovering the acheronian reddish oval connected Jupiter, Cassini and different astronomers continued to observe the tempest until 1713. For much than a period after, the tempest hadn’t been seen. It wasn’t until 1831 erstwhile astronomers observed a akin oval signifier astatine the aforesaid latitude. Since then, scientists person debated whether it was the aforesaid tempest oregon a antithetic one.

The wrongfully named ‘Permanent Spot’ apt disappeared sometime betwixt the mid-18th and 19th centuries, according to the researchers down the caller paper. Jupiter’s Great Red Spot, connected the different hand, whitethorn day backmost by astatine slightest 190 years.

The Great Red Spot is besides overmuch larger than its older counterpart, extending implicit 200 miles (350 kilometers). When it was archetypal observed, the Great Red Spot extended implicit 24,200 miles (39,000 kilometers) but it has been shrinking ever since. Today, the tempest stretches to 8,700 miles (14,000 kilometers) and has go much rounded successful shape. Earlier observations of the Permanent Spot suggest the tempest would person had to triple successful size to comparison to the Great Red Spot, according to the study.

Cassini’s drawings of the reddish spot successful the 1600'sImage: G. D. Cassini / Eric Sussenbach / AGU

The Red Spot is the largest known tempest successful the star system, taking up one-sixth the diameter of Jupiter itself. Unlike hurricanes connected Earth, the Great Red Spot rotates counterclockwise, which suggests that it’s a high-pressure system. The crushed wherefore the tempest has been capable to rage connected for each those years whitethorn person to bash with Jupiter’s gaseous nature. Storms connected Earth thin to dissipate erstwhile they scope land, but Jupiter is made up of liquid layers alternatively of a coagulated surface.

Understanding the elephantine tempest is not easy, with Jupiter’s clouds obstructing a wide presumption of the Great Red Spot successful its little atmosphere. The caller survey suggests the Red Spot could person formed from a gigantic superstorm, with respective smaller vortices merging together. There’s inactive overmuch to larn astir Jupiter’s raging storms, but scientists tin crook to historical observations to stitchery clues astir the Jovian system’s mysteries.

“It has been precise motivating and inspiring to crook to the notes and drawings of Jupiter and its Permanent Spot made by the large astronomer Jean Dominique Cassini, and to his articles of the 2nd fractional of the 17th period describing the phenomenon,” Agustín Sánchez-Lavega, a planetary idiosyncratic astatine the University of the Basque Country successful Bilbao, Spain, and pb writer of the caller paper, said successful a statement. “Others earlier america had explored these observations, and present we person quantified the results.”

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