New research suggests Jupiter's Great Red Spot is made up of simple chemicals being broken apart by sunlight in the planet's upper atmosphere, which is contrary to previous belief.
In the past researchers believed the color of the spot came from the reddish chemicals beneath Jupiter's clouds, NASA reported.
To make their findings the researchers blasted ammonia and acetylene gases (which exist on Jupiter) with ultraviolet light to simulate how the sun would affect this material. The method produced red-colored material similar to what is seen in the Great Red Spot. They found the light-scattering properties of their model matched those of the Spot.
"Our models suggest most of the Great Red Spot is actually pretty bland in color, beneath the upper cloud layer of reddish material," Baines said. "Under the reddish 'sunburn' the clouds are probably whitish or grayish."
Jupiter is composed almost entirely of hydrogen and helium, and researchers are interested in how these elements give Jupiter its distinctive red color.
At first the scientists looked at how the sun broke down the molecule ammonium hydrosulfide, which makes up Jupiter's main cloud layer. They found this combination didn't produce red at all, but rather a brilliant shade of green. The team then looked at simple combinations of ammonia with hydrocarbons that exist at Jupiter's high altitudes. The results show the breakdown of ammonia and acetylene through ultraviolet light would produce what is seen on the Red Planet.
The team believes the Great Red Spot is such a vivid color because of its height, which can enhance the reddening. The spot's winds transport ammonia particles higher into the atmosphere than usual, allowing them to be exposed to ultraviolet light. The vortex-like qualities of the spot also keep the particles from escaping, causing the region to always appear red in color.
The findings were presented at the American Astronomical Society's Division for Planetary Science Meeting.
