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Jupiter's Great Red Spot shrinking before our eyes

May 16, 2014 / 11:24 AM EDT / CBS News/AP

NASA video from the Hubble Space Telescope clearly show that Jupiter's Great Red Spot is shrinking. The images, spanning the course of 20 years, indicate that the spot - which is actually a massive storm - is narrowing faster than ever before

Watch: NASA video shows Jupiter's Great Red Spot is shrinking 00:33

Jupiter's Great Red Spot seems to be on a cosmic diet, shrinking rapidly before our eyes.

Astronomers using the Hubble Space Telescope calculate that the spot, a giant long-lasting storm, is narrowing by about 580 miles a year, much faster than before.

Jupiter's trademark Great Red Spot -- a swirling storm feature larger than Earth -- has shrunken to its smallest size ever measured. Astronomers have followed this downsizing since the 1930s. This series of images taken by NASA's Hubble Space Telescope documents the storm over time, beginning in 1995 with a view from the telescope's Wide Field and Planetary Camera 2 (WFPC2) when the long axis of the Great Red Spot was estimated to be 13,020 miles (20,950 kilometers) across. This camera was built by NASA's Jet Propulsion Laboratory in Pasadena, California, and corrected the telescope's initial blurry vision. In a 2009 photo, after WFPC2 had been replaced by the Wide Field Camera 3 (WFC3), the storm was measured at 11,130 miles (17,910 kilometers) across. NASA/ESA/Goddard Space Flight Center/A. Simon

Observations dating as far back as the late 1800s show that the red spot was an oval 25,500 miles wide. Beginning in 2012, it appeared to shrink at a much faster pace, with current data indicating a circle that's 10,250 miles across.

"In our new observations it is apparent that very small eddies are feeding into the storm," Amy Simon, of NASA's Goddard Space Flight Center, said in a press release. "We hypothesized that these may be responsible for the accelerated change by altering the internal dynamics and energy of the Great Red Spot."

Michael Wong, a scientist at the University of California, Berkeley, told The Associated Press that the spot is a mystery. Astronomers don't know why it's red or shrinking, or what will happen next. If this pace continues, in 17 years the spot could be gone. Or it could stop at a smaller size.

Another possible theory is the spot eats smaller storms, and that it is consuming fewer of them, says Wong.

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