Washington DC: NASA's Hubble Space Telescope's planetary portrait has captured new changes in Jupiter's Great Red Spot.
Scientists have produced new maps of Jupiter, the first in a series of annual portraits of the solar system's outer planets.
Already, the Jupiter images have revealed a rare wave just north of the planet's equator and a unique filamentary feature in the core of the Great Red Spot not seen previously.
"Every time we look at Jupiter, we get tantalizing hints that something really exciting is going on," said planetary scientist Amy Simon, adding "this time is no exception."
Simon and her colleagues produced two global maps of Jupiter from observations made using Hubble's high-performance Wide Field Camera 3. The two maps represent nearly back-to-back rotations of the planet, making it possible to determine the speeds of Jupiter's winds.
The new images confirm that the Great Red Spot continues to shrink and become more circular, as it has been doing for years. The long axis of this characteristic storm is about 150 miles (240 kilometers) shorter now than it was in 2014. Recently, the storm had been shrinking at a faster-than-usual rate, but the latest change is consistent with the long-term trend.
The Great Red Spot remains more orange than red these days, and its core, which typically has more intense color, is less distinct than it used to be. An unusual wispy filament is seen, spanning almost the entire width of the vortex. In Jupiter's North Equatorial Belt, the researchers found an elusive wave that had been spotted on the planet only once before, decades earlier, by Voyager 2.
The findings appear online in Astrophysical Journal paper.