by Gas giant Jupiter steals the show in these two new portraits of the planet’s contrasting faces, showing the whirlwinds and cloud bands blown by winds gusting hundreds of miles per hour.
The IS Hubble Space Telescope These images were taken on January 5-6, 2024. Jupiter rotates once every 10 hours, Hubble was able to image one hemisphere with the famous Big Red Spot visible, and wait for the other hemisphere to appear before imaging that.
The latest images show that Jupiter is doing some action right now. “The big storms and little white clouds are a hallmark of a lot of activity going on in Jupiter’s atmosphere right now,” Simon said in a press release.
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Jupiter went through perihelion — the closest point in their orbit around the sun — on January 21, 2023, and the extra heat of the Jovian summer sun a year later appears to still be fueling its atmosphere.
The gas giant’s most distinctive feature is its dark and light banding, visible through its four inch backyard telescope. With Hubble’s vision, we see every detail of those bands. The lighter bands are called ‘zones’ and are areas where the atmosphere is rising. The darker bands are referred to as ‘belts’ and are areas where the atmosphere is sinking. The entire atmosphere is turbulent as it rotates around Jupiter, but it doesn’t rise or sink too much — the clouds are only about 30 miles (50km) deep, which is a shallow layer compared to the rest of the an atmosphere that stretches for miles. thousands of miles deep.
In one hemisphere we can see the famous Great Red Spot, which has raged for at least nearly 200 years, and possibly for much longer if the same storm had been observed from English astronomer Robert Hooke and Italian Giovanni Cassini and 1664–5. . However, there is a big question mark over the continued longevity of the Great Red Spot, because it is shrinking at an alarming rate.
At the end of the nineteenth century the Great Red Spot was measured to be about 25,500 miles (41,000 km) across, with enough space to fit three Earths within it. However, when the Voyager 1 and Game Voyager 2 spacecraft that flew past Jupiter in 1979 measured the Great Red Spot to be 14,500 miles (23,300 km) in diameter; by 1995, when Hubble looked at Jupiter, its diameter had shrunk to 13,020 miles (20,950km).
In 2014 it was 10,250 miles (16,500 km); in 2021 only 9,165 miles (14,750 km); and in November 2023 ace amateur astrophotographer Damian Peach measured it to be 7,770 miles (12,500km). The Great Red Spot has gone from being an oval large enough to fit three Earths, to being circular and not large enough to fit a single Earth (which has diameter 7,926 miles (12,756 km).
The cause of this contraction is still a mystery. Is the Great Red Spot going to blow itself out, or will it get a second wind in the future? One of the objectives of OPAL is to track the Great Red Spot and monitor how it is changing to try to work out what is happening to it.
However, its size is still impressive – a massive storm the size of our planet, with roots 500km (~300 miles) deep in the Jovian atmosphere and with winds raging between 430 and 680 kilometers per hour (267-422 mph)!
The Great Red Spot is not the only red spot on Jupiter, however. In the late 1990s three ‘white ovals’ — smaller storms seen during the twentieth century — came together to form a new storm known as Oval BA. Then, in 2006 Oval BA turned red, prompting the nickname ‘Red Spot Junior’. It has also shrunk slightly over the years, and is visible below and to the right of the Great Red Spot in the Hubble image.
What does the storms turn red is another unanswered mystery. Obviously it has to do with chemistry, maybe it has to do with the dredging of phosphorus or sulphur, or organic molecules that react with the sun’s ultraviolet light when they rise up into the cloud deck.
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At first glance the other hemisphere looks a little more bland without the two big red spots to spice things up, but on closer inspection there’s plenty going on. In the planet’s North Equatorial Zone (the first red band north of the equator) we see two smaller storms, one deep red, one brighter red, colliding next to each other. The deep red storm is a cyclone, meaning it rotates counterclockwise in Jupiter’s northern hemisphere, while its brighter, clockwise-rotating companion is an anticyclone. Because they are whirling in opposite directions they will not be together, but will bounce apart.
And as an added bonus, on the left side of the image near the South Equatorial Belt limb, we can see Jupiter’s innermost moon, the volcano and the flare. Io.
Hubble’s portraits of Jupiter, and the other gas giants, are an annual event as part of the Outer Planet Atmospheric Legacy (OPAL) program, led by planetary scientist Amy Simon of NASA’s Goddard Space Flight Center. With the help of Hubble and an army of amateur astronomers around the world, OPAL is able to keep tabs on the giant planets and monitor activity in their atmospheres.
