Jupiter's Great Red Spot maybe the most famous anti-cyclone storm in the solar system. It's famous depictions are something we all learned in school, and has become a marvel for astronomers both professional and amateur.
The thing is, it's getting smaller, and we don't fully understand why:
GRS_sizecomparison_by-Peach.jpg
It is suggested by some that eddies may be changing the dynamics of the region near the GRS.
http://hubblesite.org/newscenter/arc...14/24/image/a/
You can observe Jupiter with the naked eye tonight along side Venus. Look into the West shortly after sunset and you will see two bright stars, the 'fainter' one is Jupiter, while the other is actually Venus.
A good set of binoculars or 2.5 inch telescope will reveal a large amount of detail for both -- including Jupiter's moons.
The thing is, it's getting smaller, and we don't fully understand why:
GRS_sizecomparison_by-Peach.jpg
It is suggested by some that eddies may be changing the dynamics of the region near the GRS.
http://hubblesite.org/newscenter/arc...14/24/image/a/
Jupiter's trademark Great Red Spot — a swirling anticyclonic storm feature larger than Earth — has shrunken to the smallest size ever measured. Astronomers have followed this downsizing since the 1930s.
"Recent Hubble Space Telescope observations confirm that the Great Red Spot (GRS) is now approximately 10,250 miles across, the smallest diameter we've ever measured," said Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Md. Historic observations as far back as the late 1800s gauged the GRS to be as big as 25,500 miles on its long axis. The NASA Voyager 1 and Voyager 2 flybys of Jupiter in 1979 measured the GRS to be 14,500 miles across.
Starting in 2012, amateur observations revealed a noticeable increase in the spot's shrinkage rate. The GRS's "waistline" is getting smaller by 580 miles per year. The shape of the GRS has changed from an oval to a circle. The cause behind the shrinking has yet to be explained.
"In our new observations it is apparent that very small eddies are feeding into the storm," said Simon. "We hypothesized that these may be responsible for the accelerated change by altering the internal dynamics and energy of the Great Red Spot."
Simon's team plans to study the motions of the small eddies and also the internal dynamics of the GRS to determine if these eddies can feed or sap momentum entering the upwelling vortex.
In the comparison images one Hubble photo was taken in 1995 when the long axis of the GRS was estimated to be 13,020 miles across. In a 2009 photo, the GRS was measured at 11,130 miles across.
"Recent Hubble Space Telescope observations confirm that the Great Red Spot (GRS) is now approximately 10,250 miles across, the smallest diameter we've ever measured," said Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Md. Historic observations as far back as the late 1800s gauged the GRS to be as big as 25,500 miles on its long axis. The NASA Voyager 1 and Voyager 2 flybys of Jupiter in 1979 measured the GRS to be 14,500 miles across.
Starting in 2012, amateur observations revealed a noticeable increase in the spot's shrinkage rate. The GRS's "waistline" is getting smaller by 580 miles per year. The shape of the GRS has changed from an oval to a circle. The cause behind the shrinking has yet to be explained.
"In our new observations it is apparent that very small eddies are feeding into the storm," said Simon. "We hypothesized that these may be responsible for the accelerated change by altering the internal dynamics and energy of the Great Red Spot."
Simon's team plans to study the motions of the small eddies and also the internal dynamics of the GRS to determine if these eddies can feed or sap momentum entering the upwelling vortex.
In the comparison images one Hubble photo was taken in 1995 when the long axis of the GRS was estimated to be 13,020 miles across. In a 2009 photo, the GRS was measured at 11,130 miles across.
A good set of binoculars or 2.5 inch telescope will reveal a large amount of detail for both -- including Jupiter's moons.
Comment