Aurora on Neptune confirmed after decades of suspicion
The James Webb Space Telescope helped scientists confirm the celestial lights on one of the most mysterious planets in our solar system.
New images from NASA’s James Webb Space Telescope are showing auroras around Neptune for the first time. The discovery will allow scientists to study aspects of the planet that have previously been out of reach.
Neptune harbors cosmic secrets, in part because of its distance from Earth. But researchers have just unlocked one of the planet's mysteries by using the unique capabilities of the James Webb Space Telescope to spot auroras glowing in its atmosphere.
“It was so stunning to not just see the auroras, but the detail and clarity of the signature really shocked me,” said Henrik Melin, lead author of a study focused on the planet. “Turns out, actually imaging the auroral activity on Neptune was only possible with Webb’s near-infrared sensitivity."
This marks the first time the celestial lights have been confirmed on Neptune, although scientists had long suspected the phenomenon occasionally occurs on the planet.
At the left, an enhanced-color image of Neptune from NASA’s Hubble Space Telescope. At the right, that image is combined with data from NASA’s James Webb Space Telescope. The cyan splotches, which represent auroral activity, are data from Webb. (NASA, ESA, CSA, STScI, Heidi Hammel (AURA), Henrik Melin (Northumbria University), Leigh Fletcher (University of Leicester), Stefanie Milam (NASA-GSFC))
The auroras on the distant world differ greatly than those seen on Earth, particularly where the lights appear on the planet.
"Instead of being confined to the planet’s northern and southern poles, Neptune’s auroras are located at the planet’s geographic mid-latitudes — think where South America is located on Earth," NASA explained. This is due to Neptune’s magnetic field being tilted 47 degrees on its axis.
The study also found that part of Neptune's atmosphere has cooled dramatically since 1989, when Voyager 2 flew past the planet. “I was astonished — Neptune’s upper atmosphere has cooled by several hundreds of degrees,” Melin said. “In fact, the temperature in 2023 was just over half of that in 1989.”
Neptune fast facts:
•It takes Neptune 165 years to complete one orbit around the sun
•Neptune was discovered on Sept. 23, 1846
•Voyager 2 is the only spacecraft to have visited the planet, making its closest approach on Aug. 25, 1989
•Neptune has "dark spots," massive storms that can last for years
•The planet appears blue due to the methane in its atmosphere
