New observations of Jupiter have provided some intriguing highlights into its complex atmosphere thanks to the keen eyes of Gemini North and the Hubble Space Telescope. These two instruments have delivered observations from the infrared portion of the electromagnetic spectrum all the way to the ultraviolet, beyond the visible light that humans can see.
Different features and altitudes of the Jovian atmosphere appear differently on the electromagnetic spectrum and this provides precious insights into what is going on in the outer layers of the Solar System’s biggest planet. The part of the atmosphere that we can see here is just several hundred kilometers (a few hundred miles) thick.
As always the most prominent feature in visible light is the Great Red Spot. This is an enormous storm larger than our own planet. It is a whopping 16,350 kilometers (10,160 miles) across. This gigantic storm has been raging for 350 years and is actively shrinking and changing. It is now less than half the width it was a century ago.
Seeing it in visible light, infrared, and ultraviolet, we can quickly spot that what makes it unique. In visible light, it is an iconic red color. In ultraviolet, it is the darkest splotch on the Jovian disk. And in infrared the feature is invisible. We can only see it because of its surroundings.
So what are the different observations telling us? While we do still not know what the Great Red Spot is made of, its molecules appear red because they absorb blue light, as is clearly seen by the ultraviolet map. The storm and its surrounding must be made by towering clouds as they block the heat coming from the planet and that’s why we don’t see much in infrared.
Similar is the case for the Red Spot Jr. Two decades ago, three storms merged into a single one (peculiarly keeping the same size) forming a smaller companion to the Great Red Spot, clearly visible in the ultraviolet.
Infrared light brings to light the hot spots, regions that appear extremely bright in the longer wavelengths but are darker in the visible and ultraviolet. There’s also the "brown barge", a not very exciting name for a very bright infrared feature. It is a hot cyclonic vortex (or maybe a series of vortices) stretching over 72,000 kilometers (nearly 45,000 miles) in the east-west direction in the Northern Hemisphere of the planet.
“The Gemini North observations were made possible by the telescope’s location within the Maunakea Science Reserve, adjacent to the summit of Maunakea,” the observation team’s leader, Mike Wong of the University of California, Berkeley said in a statement. “We are grateful for the privilege of observing Ka‘?wela (Jupiter) from a place that is unique in both its astronomical quality and its cultural significance.”