Jupiter’s Great Red Spot — one of the most iconic and well known features in the solar system — is shrinking, and nobody knows why.
The so-called “Great Red Spot” is a violent storm, which in the late 1800s was estimated to be about 40,000 kilometres in diameter – wide enough for three Earths to fit side by side.
The storm, which is the biggest in the solar system, appears as a deep red orb surrounded by layers of pale yellow, orange and white.
Winds inside the storm have been measured at several hundreds of kilometres per hour.
By the time NASA’s Voyager space probes flew by in 1979 and 1980, the spot was down to about 22,500 kilometres across.
Now, new pictures taken by the Earth-orbiting Hubble Space Telescope show Jupiter’s red spot is smaller than it has ever been, measuring less than 16,100 kilometres in diameter. It also appears more circular in shape.