Nasa says Jupiter's 'great red spot' is getting smaller
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Jupiter's most distinctive feature – a giant red spot bigger than Earth – is shrinking, images from the Hubble Space Telescope released today have revealed.
The so-called 'Great Red Spot' is a violent storm, which in the late 1800s was estimated to be about 25,000 miles (about 40,000 km) 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.
Jupiter and the The Great Red Spot in 2014, left; in 1995, top right; 2009, center right; and 2014, bottom right. Nasa says Jupiter's signature Great Red Spot is on a cosmic diet, shrinking rapidly before our eyes.
WHAT IS IT?
The spot is actually a violent storm.
The biggest in the solar system, it 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 miles per hour, NASA astronomers said
Winds inside the storm have been measured at several hundreds of miles per hour, NASA astronomers said.
By the time NASA's Voyager space probes flew by in 1979 and 1980, the spot was down to about 14,500 miles (22,500 km) 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 just under 10,250 miles (16,100 kilometers) in diameter.
It also appears more circular in shape.
Scientists aren't sure why the Great Red Spot is shrinking by about 621 miles (1,000 km) a year.
'It is apparent that very small eddies are feeding into the storm.
'These may be responsible for the accelerated change by altering the (storm's) internal dynamics,' Amy Simon, an astronomer with NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement.
Simon and colleagues plan follow-up studies to try to figure out what is happening in Jupiter's atmosphere that is draining the storm of energy and causing it to shrink.
These two frames of composit images taken by NASA's Cassini spacecraft show the same cloud patterns on Jupiter both in natural color (left) and in a false-color combination (right) selected to show differences in the clouds' height. The white spots in the right frame are storms high in the atmosphere.
Beginning in 2012, amateur observations revealed a noticeable increase in the rate at which the spot is shrinking -- by 580 miles per year -- changing its shape from an oval to a circle.
'In our new observations it is apparent very small eddies are feeding into the storm,' said Simon.
'We hypothesized these may be responsible for the accelerated change by altering the internal dynamics and energy of the Great Red Spot.'
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