{"id":13487,"date":"2025-03-27T13:31:41","date_gmt":"2025-03-27T12:31:41","guid":{"rendered":"https:\/\/www.telescoop.nl\/?p=13487"},"modified":"2025-11-27T19:32:59","modified_gmt":"2025-11-27T18:32:59","slug":"neptune-aurora","status":"publish","type":"post","link":"https:\/\/www.telescoop.nl\/en\/neptunus-noorderlicht\/","title":{"rendered":"Neptune auroras: first direct evidence of auroras on the ice giant"},"content":{"rendered":"

For the first time in history, the Neptune northern lights<\/strong> observed - not by accident, but thanks to a collaboration between the most powerful space telescopes ever built: Hubble and James Webb.<\/p>\n\n\n\n

What you see in the photo on the right is not a visual disturbance, but a combination of visible light and infrared data. Together, they suddenly bring an enigmatic, icy world to life.<\/p>\n\n\n\n

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Credit: NASA, ESA, CSA, This image was created from Hubble and Webb data from proposals: 17187<\/a> (N. Rowe-Gurney) and 1249<\/a> (L. Fletcher). Image processing: Alyssa Pagan (STScI).<\/em><\/p>\n\n\n\n

Where does the northern lights originate on Neptune?<\/h3>\n\n\n\n

On Earth, northern and southern lights appear around the magnetic poles when charged solar particles collide with oxygen and nitrogen atoms in the atmosphere. This produces the familiar green and purple glow.<\/p>\n\n\n\n

But Neptune is behaving differently. Its atmosphere is hundreds of degrees colder than expected, which has hidden the phenomenon from view until now.<\/p>\n\n\n\n

The James Webb Space Telescope (JWST) has changed all that. With the Near-Infrared Spectrograph (NIRSpec).<\/strong> auroral emissions were observed at unexpected latitudes - far away from the poles. Webb also detected a strong presence of the molecule H\u2083\u207a<\/strong>, a chemical signature of active auroras.<\/p>\n\n\n\n

This is revolutionary. It proves that even the farthest planet in our solar system is affected by space weather - and gives us new insights into how magnetic fields work on other worlds.<\/p>\n\n\n\n

What makes Neptune so unique?<\/h3>\n\n\n\n

Neptune is the eighth planet from the sun and is on average 4.5 billion kilometers away. It is a ice giant<\/strong>, composed of a core of rock and metal surrounded by water, ammonia and methane.<\/p>\n\n\n\n

The blue color is mainly due to methane in the atmosphere, which absorbs red light and reflects blue.<\/p>\n\n\n\n

What many don't know: Neptune has the fastest winds in the solar system<\/strong>, up to 2,100 mph. In addition, the planet rotates in only 16 hours<\/strong> around its axis, contributing to its dynamic weather patterns.<\/p>\n\n\n\n

Its magnetic field<\/strong> is extremely skewed: it is 47 degrees off plumb with respect to the axis of rotation. As a result, auroras appear where you would not expect them at all - a unique feature in the solar system.<\/p>\n\n\n\n

A look back: Neptune by Voyager 2<\/h3>\n\n\n\n

In addition to the new insights from Webb and Hubble, there is also a historical perspective. In 1989, Voyager 2<\/strong> past Neptune - the only space probe ever to visit the planet up close.<\/p>\n\n\n\n

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This photo was taken 7 million kilometers away, five days before its closest approach. You can see the famous Great Dark Spot<\/strong>, a bright spot next to it, the fast-moving cloud formation Scooter<\/strong>, and a small dark spot on the west side. These stormy structures remained visible as long as Voyager's cameras could track them.<\/figcaption><\/figure>\n\n\n\n

The comparison with modern images shows how far our technology has advanced: from visual storms to chemical analysis at the molecular level. Yet one thing remains the same: Neptune continues to surprise<\/strong>.<\/p>\n<\/div>\n<\/div>\n\n\n\n

What can you do with this as an amateur stargazer?<\/h3>\n\n\n\n

Neptune, with a visual brightness of magnitude 8, is not visible with the naked eye, but it is visible with a suitable telescope. Want to locate the planet yourself? Then these are excellent choices:<\/p>\n\n\n\n