Different views of Neptune. ESO/P. Irwin et al.

Neptune’s Dark Mystery: Ground-Based Telescope Reveals Astonishing Features

Neptune's mystery; a strange dark spot.


For the first time, Earth-based telescopes have captured an enigmatic dark spot on Neptune, shedding light on an atmospheric phenomenon that has puzzled astronomers for decades.

Utilizing the European Southern Observatory’s Very Large Telescope (VLT), astronomers have discovered a prominent dark spot in Neptune’s atmosphere, accompanied by a smaller, unexpected bright spot. Historically, such atmospheric dark spots have been elusive, creating a conundrum for researchers. This recent observation is significant in unlocking clues about these mysterious features.

A Brief History of Dark Spots

Giant planets like Jupiter are no strangers to prominent atmospheric features; think of Jupiter’s iconic Great Red Spot. In Neptune’s case, a dark spot was first identified by NASA’s Voyager 2 in 1989, only to vanish in the subsequent years. Reflecting on the phenomenon, Professor Patrick Irwin from the University of Oxford, the study’s lead investigator, commented, “Since the first discovery of a dark spot, I’ve been intrigued about these transient dark attributes.”

Previously, there was speculation that these spots were the result of cloud clearances. However, this latest research, documented in the paper “Cloud structure of dark spots and storms in Neptune’s atmosphere” in Nature Astronomy, suggests a different story.


Shedding Light on the Darkness

Observations from the VLT infer that these spots arise due to air particles becoming darkened beneath the principal visible haze layer, influenced by the mixing of ices and hazes in Neptune’s atmosphere.

The capability to come to such a conclusion is groundbreaking. Until the NASA/ESA Hubble Space Telescope identified several dark spots, these phenomena weren’t thoroughly investigated. However, the 2018 detection of a dark spot in Neptune’s northern hemisphere presented an invaluable opportunity.

The VLT’s Instrumental Role

With the VLT’s Multi Unit Spectroscopic Explorer (MUSE) at their disposal, the team dissected sunlight reflecting off Neptune, producing a 3D spectrum and allowing for unprecedented detailed study. Professor Irwin expressed his enthusiasm, stating, “It’s exhilarating to have made the first-ever ground-based detection of a dark spot and to record a reflection spectrum of such a feature.”

This spectrum, deciphering different wavelengths, gave insights into the spot’s position in Neptune’s atmosphere and its chemical composition, offering hints about its dark appearance.

Surprise in the Shadows

But Neptune had another revelation in store. Michael Wong, a study co-author from the University of California, Berkeley, revealed, “We identified a unique deep bright cloud that was previously undiscovered, even from space.” Found adjacent to the main dark spot, this new “deep bright cloud” is a novelty, contrasting with previously observed high-altitude methane ice clouds.


With advances in technology and the prowess of the VLT, researchers can now probe celestial features like these without leaving our planet. Wong concluded, “From needing space missions like Voyager to Hubble’s distant observations, and now to ground-based capabilities – it’s a testament to human ingenuity and our evolving capability to study the universe.”

PLEASE READ: Have something to add? Visit Curiosmos on Facebook. Join the discussion in our mobile Telegram group. Also, follow us on Google News. Interesting in history, mysteries, and more? Visit Ancient Library’s Telegram group and become part of an exclusive group.

Written by Ivan Petricevic

I've been writing passionately about ancient civilizations, history, alien life, and various other subjects for more than eight years. You may have seen me appear on Discovery Channel's What On Earth series, History Channel's Ancient Aliens, and Gaia's Ancient Civilizations among others.

Write for us

We’re always looking for new guest authors and we welcome individual bloggers to contribute high-quality guest posts.

Get In Touch