Jupiter's Great Red spot is shrinking maybe temporarily?
© Damian Peach
Graphical comparison showing how Jupiter’s Great Red Spot has shrunk in the past 125 years using photographs taken in 1890. See below for details on how it was done.
This titanic hurricane-like storm has charmed earthlings since Giovanni Cassini first spotted it in the mid-1600s. Will our grandchildren turn their telescopes to Jove only to see a pale pink oval like so many others rolling around the planet's South Tropical Zone?
Maybe.
© Michael Carroll
Jupiter’s Great Red Spot is a cyclone that’s presently about 1.2 times as big as Earth. As recently as 1979, it was twice Earth’s diameter as illustrated here.
Peach compared measurements of the Spot in black and white photos taken at Lick Observatory in California in 1890-91 with a photo he took on April 13 this year. He then manipulated his April 13 data using the Lick photos and WINJUPOS (Jupiter feature measuring program) to carefully match the storm to its dimensions and appearance 125 years ago. Voila! Now we have a good idea of what we missed by being born too late.
© Agnes Clerk’s book/A History of Astronomy in the 19th Century
At left, a crude photograph of Jupiter’s enormous Great Red Spot in 1879 from Agnes Clerk’s book
© Donato Creti
Painting by Italian artist Donato Creti showing a telescopic view of Jupiter in 1711 above a nightime landscape. The Great Red Spot is clearly visible above center.
© Anthony Wesley
Dramatic fading of Jupiter’s South Equatorial Belt (SEB) between 2009 and 2010. The belt has since returned to view. The Red Spot is also seen in both images.
© NASA
The Great Red Spot photographed by Voyager 1 in 1979 and reprocessed by Bjorn Jonsson shows an incredible wealth of detail.
Just in case it disappears unexpectedly, take one last look this observing season. Jupiter's currently getting lower in the western sky as it approaches Venus for its grand conjunction on June 30. Below are times (Central Daylight or CDT) when it crosses or transits the planet's central meridian. The GRS will be easiest to see for a 2-hour interval starting an hour before the times shown. It's located in the planet's southern hemisphere just south of the prominent South Equatorial Belt. Add an hour for Eastern time; subtract one hour for Mountain and two hours for Pacific. A complete list of transit times can be found HERE.
* June 13 at 8:58 p.m.
* June 18 at 12:16 a.m.
* June 18 at 8:08 p.m.
* June 20 at 9:47 p.m.
* June 22 at 11:26 p.m.
* June 25 at 8:57 p.m.
* June 27 at 10:36 p.m.
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