November 2, 2024

Mysterious Dark Spot on Neptune Detected From Earth for the First Time

Using ESOs Very Large Telescope (VLT), astronomers have actually observed a big dark spot in Neptunes atmosphere, with an unanticipated smaller bright spot nearby to it. This brief video summarizes their discovery. Credit: ESO
Findings From the Observations
Irwin and his team utilized data from ESOs VLT to eliminate the possibility that dark spots are caused by a clearing in the clouds. The brand-new observations show instead that dark areas are likely the outcome of air particles darkening in a layer below the main noticeable haze layer, as ices and hazes mix in Neptunes atmosphere.
Since dark spots are not permanent features of Neptunes environment and astronomers had actually never in the past been able to study them in enough detail, coming to this conclusion was no simple accomplishment. The chance followed the NASA/ESA Hubble Space Telescope discovered numerous dark spots in Neptunes atmosphere, consisting of one in the planets northern hemisphere very first discovered in 2018. Irwin and his team right away got to work studying it from the ground– with an instrument that is preferably suited to these challenging observations.
Utilizing the VLTs Multi Unit Spectroscopic Explorer (MUSE), the researchers were able to split reflected sunlight from Neptune and its spot into its part colors, or wavelengths, and acquire a 3D spectrum. “Im definitely delighted to have actually been able to not only make the first detection of a dark area from the ground, however likewise record for the extremely first time a reflection spectrum of such a function,” says Irwin.
This image reveals Neptune observed with the MUSE instrument at ESOs Very Large Telescope. At each pixel within Neptune, MUSE splits the incoming light into its constituent colors or wavelengths. This image integrates all colors caught by MUSE into a “natural” view of Neptune, where a dark spot can be seen to the upper.
Because different wavelengths probe various depths in Neptunes environment, having a spectrum enabled astronomers to much better identify the height at which the dark spot beings in the planets atmosphere. The spectrum also provided information on the chemical composition of the various layers of the environment, which offered the team clues as to why the spot appeared dark.
This rare cloud type appeared as a brilliant spot right beside the bigger main dark spot, the VLT information revealing that the brand-new deep bright cloud was at the exact same level in the atmosphere as the main dark area. This suggests it is a completely new type of feature compared to the small buddy clouds of high-altitude methane ice that have been formerly observed.
This animation shows Neptune observed with the MUSE instrument at ESOs Very Large Telescope. At each pixel within Neptune, MUSE splits the inbound light into its constituent colors or wavelengths. This is similar to obtaining images at thousands of various wavelengths at one time, which offers a wealth of important info to astronomers. In this animation we scan through all these different wavelengths, revealing various dark and bright functions. Based on the wavelengths where these features are most prominent, astronomers can find out what triggers them and how deep within Neptunes atmosphere they are situated. Credit: ESO/P. Irwin et al./ L. Calçada
Implications for Future Observations
With the aid of ESOs VLT, it is now possible for astronomers to study features like these spots from Earth. “This is an astounding increase in mankinds capability to observe the cosmos. In the beginning, we could only detect these areas by sending out a spacecraft there, like Voyager. Then we acquired the capability to make them out from another location with Hubble. Lastly, innovation has actually advanced to allow this from the ground,” concludes Wong, before adding, jokingly: “This might put me out of work as a Hubble observer!”
This animation reveals Neptune observed with the MUSE instrument at ESOs Very Large Telescope. At each pixel within Neptune, MUSE divides the incoming light into its constituent colors or wavelengths. This resembles getting images at countless various wavelengths at one time, which supplies a wealth of important info to astronomers.
The first image in this animation combines all colors recorded by MUSE into a “natural” view of Neptune, where a dark spot can be seen to the upper. We see images at specific wavelengths: 551 nanometres (blue), 831 nm (green), and 848 nm (red); note that the colors are just a sign, for display purposes.
The dark spot is most popular at shorter (bluer) wavelengths. Next to this dark spot MUSE likewise captured a little bright one, seen here just in the middle image at 831 nm and situated deep in the environment. This kind of deep intense cloud had never ever been identified before on the planet. The images likewise show several other shallower brilliant spots towards the bottom-left edge of Neptune, seen at long wavelengths.
Imaging Neptunes dark area from the ground was only possible thanks to the VLTs Adaptive Optics Facility, which corrects the blur triggered by atmospheric turbulence and enables MUSE to get crystal-clear images. To better highlight the subtle dark and intense functions in the world, the astronomers thoroughly processed the MUSE information, getting what you see here.
Credit: ESO/P. Irwin et al
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Astronomers utilizing the European Southern Observatorys Very Large Telescope (VLT) have actually determined a substantial dark area in Neptunes environment, with a surrounding smaller sized brilliant spot. Using the European Southern Observatorys Very Large Telescope (VLT), astronomers have observed a big dark spot in Neptunes environment, with an unforeseen smaller brilliant area nearby to it. Large areas are typical features in the environments of huge worlds, the most well-known being Jupiters Great Red Spot. Utilizing ESOs Very Large Telescope (VLT), astronomers have actually observed a big dark area in Neptunes atmosphere, with an unexpected smaller intense spot adjacent to it. This uncommon cloud type appeared as a brilliant area right next to the larger primary dark area, the VLT information showing that the new deep brilliant cloud was at the same level in the atmosphere as the main dark area.

Notes MUSE is a 3D spectrograph that permits astronomers to observe the totality of an astronomical item, like Neptune, in one go. At each pixel, the instrument determines the intensity of light as a function of its color or wavelength. The resulting information form a 3D set in which each pixel of the image has a full spectrum of light. In total, MUSE procedures over 3500 colors. The instrument is designed to make the most of adaptive optics, which corrects for the turbulence in the Earths environment, resulting in sharper images than otherwise possible. Without this combination of functions, studying a Neptune dark area from the ground would not have actually been possible.

This image reveals Neptune observed with the MUSE instrument at ESOs Very Large Telescope (VLT). At each pixel within Neptune, MUSE divides the incoming light into its constituent colors or wavelengths. Astronomers utilizing the European Southern Observatorys Very Large Telescope (VLT) have actually identified a substantial dark area in Neptunes environment, with a nearby smaller brilliant area.
Using the European Southern Observatorys Very Large Telescope (VLT), astronomers have actually observed a large dark spot in Neptunes environment, with an unanticipated smaller sized brilliant spot surrounding to it. This is the first time a dark area on the world has actually ever been observed with a telescope on Earth. These occasional features in the blue background of Neptunes environment are a secret to astronomers, and the brand-new outcomes supply additional clues regarding their nature and origin.
Big areas are typical functions in the environments of huge worlds, the most famous being Jupiters Great Red Spot. On Neptune, a dark spot was first found by NASAs Voyager 2 in 1989, before vanishing a few years later on. “Since the first discovery of a dark spot, Ive always wondered what these temporary and elusive dark functions are,” says Patrick Irwin, Professor at the University of Oxford in the UK and lead investigator of the research study published on August 24 in Nature Astronomy.

Reference: “Spectral decision of the colour and vertical structure of dark spots in Neptunes atmosphere” by Patrick G. J. Irwin, Jack Dobinson, Arjuna James, Michael H. Wong, Leigh N. Fletcher, Michael T. Roman, Nicholas A. Teanby, Daniel Toledo, Glenn S. Orton, Santiago Pérez-Hoyos, Agustin Sánchez-Lavega, Lawrence Sromovsky, Amy A. Simon, Raúl Morales-Juberías, Imke de Pater and Statia L. Cook, 24 August 2023, Nature Astronomy.DOI: 10.1038/ s41550-023-02047-0.
, Agustin Sánchez Lavega (UPV/EHU), Lawrence Sromovsky (University of Wisconsin, USA), Amy Simon (Solar System Exploration Division, NASA Goddard Space Flight Center, USA), Raúl Morales-Juberias (New Mexico Institute of Technology, USA), Imke de Pater (Berkeley), and Statia L. Cook (Columbia University, USA).