Hubble telescope shows Jupiter's Little Red Spot growing stronger

The highest wind speeds in Jupiter's Little Red Spot have increased and are now equal to those in its older and larger sibling, the Great Red Spot, according to observations with NASA's Hubble Space Telescope.

The Little Red Spot's winds, now raging up to approximately 400 miles per hour (about 645 km per hour), signal that the storm is growing stronger, said the NASA-led team that made the Hubble observations.

The increased intensity of the storm probably caused it to change color from its original white in late 2005 to red, the findings published by the team claimed on NASA's website on Wednesday.

"No one has ever seen a storm on Jupiter grow stronger and turn red before," said Amy Simon-Miller of NASA's Goddard Space Flight Center. "We hope continued observations of the Little Red Spot will shed light on the many mysteries of the Great Red Spot, including the composition of its clouds and the chemistry that gives it its red color."

Although it seems small when viewed against Jupiter's vast size, the Little Red Spot is actually about the size of Earth, and the Great Red Spot is around three times Earth's diameter across. Both are giant storms in Jupiter's southern hemisphere, powered by warm air rising in their centers.

The Little Red Spot is the only survivor among three white-colored storms that merged together. In the 1940s, the three storms were seen forming in a band slightly below the Great Red Spot. In 1998, two of the storms merged into one, which then merged with the third storm in 2000.

In 2005, amateur astronomers noticed that this merged, larger storm was changing color, and it became known as the Little Red Spot after becoming noticeably red in early 2006.

Scientists are not sure why the Little Red Spot is growing stronger. One possibility is a change in size. These storms naturally fluctuate in size, and their winds spin around their central core of rising air. If the storm were to become smaller, its spiraling winds would increase the same way spinning ice skaters turn faster by pulling their arms closer to their bodies.

Another possibility is that it's the only survivor. "The lack of other large storms in the same latitude on Jupiter leaves more energy to feed the Little Red Spot," said Simon-Miller.

Source: Xinhua