Neptune is so far away — at an astonishing 3 billion miles from the sun — that there ’s a band we still do n’t know about this satellite . Fromfluctuating temperaturesto thediscovery of petite moons thereto even debates about theplanet ’s true colour , Neptune continues to storm . Now , though , investigator have uncovered another distinctive feature there : a bright auroral glow .
Neptune often looks slightly different in observations , as it hasdark situation which come out periodically . But it can also be vivid at times , as the observance of dawning there show : In the look-alike above , the auroras are shown in the cyan color .
Spotted by the James Webb Space Telescope , auroras occur when energetic speck from the sun interact with a planet ’s atmosphere , creating a glowing light show . It ’s the same event that is reckon on Earth ( and often call the Northern Lights ) , and it has also been seen on other planets likeMars — but this is the first time it ’s been spotted on Neptune .
“ Turns out , actually imaging the auroral body process on Neptune was only possible with Webb ’s near - infrared predisposition , ” say jumper lead researcher Henrik Melin of Northumbria University . “ It was so arresting to not just see the daybreak , but the detail and clearness of the signature really shocked me . ”
The data was collected using a Webb instrument call the Near - Infrared spectrogram which can also tell what is present in the satellite ’s atmosphere . It happen indications of a molecule called trihydrogen cation ( H3 + ) , thought to be created by dawning .
“ H3 + has a been a clear signifier on all the gas giants — Jupiter , Saturn , and Uranus — of auroral activity , and we expect to see the same on Neptune as we investigated the planet over the years with the best ground - base facilities available , ” explicate Webb scientist Heidi Hammel . “ Only with a machine like Webb have we at last gotten that confirmation . ”
However , despite the similarities with auroral activites on other planets in the solar system , Neptune ’s first light have a character all of their own . Because of the way the planet revolve — almost entirely tap over onto its side — its auroras are n’t over its Frederick North and south poles like they are on other planets . In researching the phenomenon , the scientist also found that the very top of Neptune ’s atmosphere was quite different from what they expected .
“ I was astonished — Neptune ’s upper atmosphere has cooled by several one C of level , ” Melin said . “ In fact , the temperature in 2023 was just over half of that in 1989 . ”
Now , with Webb , scientist are finally able to read the unusual mysteries of Neptune — such as how its atmosphere is cooling so fast .
“ As we wait ahead and dream of future missionary station to Uranus and Neptune , we now have intercourse how significant it will be to have instruments tune up to the wavelengths of infrared light to go along to study the break of day , ” said fellow researcher Leigh Fletcher of Leicester University . “ This lookout has finally opened the windowpane onto this last , previously hide ionosphere of the elephantine satellite . ”
The research is published inNature Astronomy .
