'Neptune just got weirder': James Webb solves a 35-year-old mystery
Produced by: Mohsin Shaikh
Aurora Breakthrough
For the first time ever, Neptune’s elusive auroras have been captured in vivid detail, thanks to the near-infrared vision of the James Webb Space Telescope.
35-Year Mystery
Voyager 2 hinted at Neptune’s auroras in 1989—but Webb finally confirmed them with glowing clarity in 2023, ending decades of speculation.
Cyan Glow
These shimmering lights appear as cyan patches—created when solar particles slam into Neptune’s atmosphere and emit energy as visible light.
Credit: NASA, ESA
Molecular Marker
Webb detected a clear signal of H₃⁺, a charged hydrogen molecule that acts as a cosmic tracer for auroras on gas giants. Neptune’s glow is now official.
Auroras Off-Track
Unlike Earth’s polar auroras, Neptune’s appear at mid-latitudes due to its magnetic field being tilted 47° off-axis—a planetary oddity revealed by Voyager 2.
Deep Freeze
Webb found that Neptune’s upper atmosphere has cooled by hundreds of degrees since 1989—possibly the reason past telescopes missed the auroras.
Frozen Surprise
Neptune, 30 times farther from the Sun than Earth, shows that solar activity still influences its atmosphere—proving our star’s reach goes deeper than expected.
Magnetic Mystery
These auroras may hold clues to Neptune’s bizarre magnetic field—one of the most asymmetrical in the solar system and still largely unexplained.
Next Giant Leap
This discovery reshapes the future of planetary exploration, showing that infrared instruments are key to unlocking secrets of the outer solar system.