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Discovery Alert: a ‘Hot Neptune’ in a Tight Orbit
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By NASA
6 Min Read NASA’s Webb Captures Neptune’s Auroras For First Time
At the left, an enhanced-color image of Neptune from NASA’s Hubble Space Telescope. At the right, that image is combined with data from NASA’s James Webb Space Telescope. Credits:
NASA, ESA, CSA, STScI, Heidi Hammel (AURA), Henrik Melin (Northumbria University), Leigh Fletcher (University of Leicester), Stefanie Milam (NASA-GSFC) Long-sought auroral glow finally emerges under Webb’s powerful gaze
For the first time, NASA’s James Webb Space Telescope has captured bright auroral activity on Neptune. Auroras occur when energetic particles, often originating from the Sun, become trapped in a planet’s magnetic field and eventually strike the upper atmosphere. The energy released during these collisions creates the signature glow.
In the past, astronomers have seen tantalizing hints of auroral activity on Neptune, for example, in the flyby of NASA’s Voyager 2 in 1989. However, imaging and confirming the auroras on Neptune has long evaded astronomers despite successful detections on Jupiter, Saturn, and Uranus. Neptune was the missing piece of the puzzle when it came to detecting auroras on the giant planets of our solar system.
“Turns out, actually imaging the auroral activity on Neptune was only possible with Webb’s near-infrared sensitivity,” said lead author Henrik Melin of Northumbria University, who conducted the research while at the University of Leicester. “It was so stunning to not just see the auroras, but the detail and clarity of the signature really shocked me.”
The data was obtained in June 2023 using Webb’s Near-Infrared Spectrograph. In addition to the image of the planet, astronomers obtained a spectrum to characterize the composition and measure the temperature of the planet’s upper atmosphere (the ionosphere). For the first time, they found an extremely prominent emission line signifying the presence of the trihydrogen cation (H3+), which can be created in auroras. In the Webb images of Neptune, the glowing aurora appears as splotches represented in cyan.
Image A:
Neptune’s Auroras – Hubble and Webb
At the left, an enhanced-color image of Neptune from NASA’s Hubble Space Telescope. At the right, that image is combined with data from NASA’s James Webb Space Telescope. The cyan splotches, which represent auroral activity, and white clouds, are data from Webb’s Near-Infrared Spectrograph (NIRSpec), overlayed on top of the full image of the planet from Hubble’s Wide Field Camera 3. NASA, ESA, CSA, STScI, Heidi Hammel (AURA), Henrik Melin (Northumbria University), Leigh Fletcher (University of Leicester), Stefanie Milam (NASA-GSFC) “H3+ has a been a clear signifier on all the gas giants — Jupiter, Saturn, and Uranus — of auroral activity, and we expected to see the same on Neptune as we investigated the planet over the years with the best ground-based facilities available,” explained Heidi Hammel of the Association of Universities for Research in Astronomy, Webb interdisciplinary scientist and leader of the Guaranteed Time Observation program for the Solar System in which the data were obtained. “Only with a machine like Webb have we finally gotten that confirmation.”
The auroral activity seen on Neptune is also noticeably different from what we are accustomed to seeing here on Earth, or even Jupiter or Saturn. Instead of being confined to the planet’s northern and southern poles, Neptune’s auroras are located at the planet’s geographic mid-latitudes — think where South America is located on Earth.
This is due to the strange nature of Neptune’s magnetic field, originally discovered by Voyager 2 in 1989 which is tilted by 47 degrees from the planet’s rotation axis. Since auroral activity is based where the magnetic fields converge into the planet’s atmosphere, Neptune’s auroras are far from its rotational poles.
The ground-breaking detection of Neptune’s auroras will help us understand how Neptune’s magnetic field interacts with particles that stream out from the Sun to the distant reaches of our solar system, a totally new window in ice giant atmospheric science.
From the Webb observations, the team also measured the temperature of the top of Neptune’s atmosphere for the first time since Voyager 2’s flyby. The results hint at why Neptune’s auroras remained hidden from astronomers for so long.
“I was astonished — Neptune’s upper atmosphere has cooled by several hundreds of degrees,” Melin said. “In fact, the temperature in 2023 was just over half of that in 1989.”
Through the years, astronomers have predicted the intensity of Neptune’s auroras based on the temperature recorded by Voyager 2. A substantially colder temperature would result in much fainter auroras. This cold temperature is likely the reason that Neptune’s auroras have remained undetected for so long. The dramatic cooling also suggests that this region of the atmosphere can change greatly even though the planet sits over 30 times farther from the Sun compared to Earth.
Equipped with these new findings, astronomers now hope to study Neptune with Webb over a full solar cycle, an 11-year period of activity driven by the Sun’s magnetic field. Results could provide insights into the origin of Neptune’s bizarre magnetic field, and even explain why it’s so tilted.
“As we look ahead and dream of future missions to Uranus and Neptune, we now know how important it will be to have instruments tuned to the wavelengths of infrared light to continue to study the auroras,” added Leigh Fletcher of Leicester University, co-author on the paper. “This observatory has finally opened the window onto this last, previously hidden ionosphere of the giant planets.”
These observations, led by Fletcher, were taken as part of Hammel’s Guaranteed Time Observation program 1249. The team’s results have been published in Nature Astronomy.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
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Media Contacts
Laura Betz – laura.e.betz@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Hannah Braun- hbraun@stsci.edu
Space Telescope Science Institute, Baltimore, Maryland
Christine Pulliam – cpulliam@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
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Henrik Melin (Northumbria University)
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Last Updated Mar 25, 2025 Editor Stephen Sabia Contact Laura Betz laura.e.betz@nasa.gov Related Terms
James Webb Space Telescope (JWST) Astrophysics Goddard Space Flight Center Neptune Planetary Science Planets Science & Research The Solar System View the full article
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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
A NASA researcher and innovation architect from the Convergent Aeronautics Solutions project Discovery team collaborating at a whiteboard during a visit to Chapel Hill, N.C. on Aug. 13, 2024.NASA / Ariella Knight Convergent Aeronautics Solutions (CAS) Discovery identifies problems worth solving for the benefit of all.
We formulate “convergent” problems—across multiple disciplines and sectors—and build footholds toward potentially transformative opportunities in aeronautics. As aeronautics rapidly advances, it is increasingly intersecting with other sectors like energy, healthcare, emergency response, economic resilience, the space economy, and more.
CAS Discovery builds new innovation tools and methods, a workforce adept at innovation methods, and transdisciplinary teams of researchers within and beyond NASA that conduct regular “Discovery sprints”—expeditions into cross-sector topic areas that could beneficially transform aeronautics and humanity.
WHAT is Discovery?
Participatory
It is difficult to understand and effectively address stakeholders’ needs & capabilities without engaging them. Discovery, in consultation with key NASA offices and other government agencies, has honed mechanisms to lawfully and respectfully engage and invite participation from stakeholders, communities, industry, NGOs and government to collaboratively formulate complex societal challenges tied to aviation.
Convergent
Typical organizational structures limit convergence across knowledge boundaries. CAS Discovery is intentionally cross-sector and transdisciplinary because the most impactful ideas often lie at the intersection of boundaries, the borderlands where multiple disciplines and communities come together. We work to emerge multi-sector, system-of-systems challenges that integrate political, economic, social, technological, environmental, legal and ethical trends, needs, and capabilities.
Future-Focused
Organizations have a tendency of being driven by short-term thinking and relatively short time horizons. CAS Discovery uses strategic foresight methods to examine 20 to 50-year time horizons, systematically ingesting and synthesizing signals and trends from aero and non-aero sources to envision a variety of scenarios to uncover opportunities for the future of aeronautics.
Ecosystemic
We study the ecosystems that are part of aeronautics and aerospace. This helps in broadening consideration of impacts while practicing foresight. It enhances our awareness of the environment and gives stakeholders the ability to see ripple effects across technologies, economies, communities, etc. We seek to benefit the wellness of the entire ecosystem while also benefiting the constituents.
A group of NASA researchers and leaders from the Convergent Aeronautics Solutions project Discovery team at the agency’s Glenn Research Center in Cleveland, on April 30, 2024.NASA / Ricaurte Chock WHO is Discovery?
NASA Researchers
They are the engine that propels CAS Discovery. Our cross-center Discovery sprint and foresight teams are composed of researchers from NASA’s Ames Research Center and Armstrong Flight Research Center in California, Glenn Research Center in Cleveland, and Langley Research Center in Virginia.
Researchers from Outside of NASA
They collaborate with us as subject matter experts or Discovery sprint team members to contribute their backgrounds in fields less common within NASA, such as energy, economics, anthropology, and other areas. This collaboration happens through many mechanisms, such as freelancing, crowdsourcing, interviews, webinars, and podcasts.
Stakeholders
They are engaged in various ways and to different degrees, often co-envisioning potential futures, co-formulating problems, and co-designing solutions.
Innovation Architects
They are the glue that holds CAS Discovery together and the anti-glue that keeps our teams from getting stuck. They come from a wide range of experience, each bringing deep expertise in leading transdisciplinary teams and stakeholders through processes and methods from strategic foresight, complex systems design, human-centered design, and more.
CAS Center Integration Leads (CILs)
They work with NASA line management at each Aeronautics center to bring NASA researchers and potential new PIs into CAS. CILs also host annual Wicked Wild idea pitch events to bring new problem areas and solution ideas into CAS Discovery and early Execution phases.
Ames Research Center CIL: Ty Huang Armstrong Flight Research Center CIL: Matt Kearns Glenn Research Center CIL: Jeffrey Chin Langley Research Center CIL: Devin Pugh-Thomas CAS Discovery Leads
They oversee Discovery sprint and strategic foresight teams, topics, and processes; new tools and continuous improvement experiments; and the overall health of the CAS innovation front-end pipeline and related strategic outputs.
Discovery Lead: Eric Reynolds Brubaker, Langley Research Center Foresight Lead: Vikram Shyam, Glenn Research Center Sample Discovery Publications
COMING SOON: Links to Technical Memorandums and conference papers.
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Last Updated Mar 21, 2025 EditorJim BankeContactDiana Fitzgeralddiana.r.fitzgerald@nasa.gov Related Terms
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By NASA
Artist’s rendering of a potentially habitable super-Earth orbiting a star called HD 20794. Illustration credit: Gabriel Pérez Díaz, SMM (IAC) The Discovery
A possible “super-Earth” orbits a relatively close, Sun-like star, and could be a habitable world – but one of extreme temperature swings, from scorching heat to deep freeze.
Key Facts
The newly confirmed planet is the outermost of three detected so far around a star called HD 20794, just 20 light-years from Earth. Its 647-day orbit is comparable to Mars in our solar system. But this planet’s orbit is highly eccentric, stretched into an oval shape. That brings the planet close enough to the star to experience runaway heating for part of its year, then carries it far enough away to freeze any potential water on its surface. The planet has been bouncing between these extremes roughly every 300 days – perhaps for billions of years.
Details
The planet spends a good chunk of its year in the “habitable zone” around its star, the orbital distance that would allow liquid water to form on the surface under the right atmospheric conditions. But because of its eccentric orbit, it moves to a distance interior to the inner edge of the habitable zone when closest to the star, and outside the outer edge when farthest away. At its closest, the planet’s distance from the star is comparable to Venus’s distance from the Sun; at its farthest point, it is nearly twice the distance from Earth to the Sun. The planet is possibly rocky, like Earth, but could be a heftier version – about six times as massive as our home planet.
Star HD 20794 and its posse of possible planets have been extensively studied, but the international team of astronomers that confirmed the outer planet, led by Nicola Nari of Light Bridges S.L. and the Instituto de Astrofisica de Canarias, examined more than 20 years worth of data to pin down all three planets’ orbits and likely masses.
The scientists relied on data from two ground-based, precision instruments: HARPS, the High Accuracy Radial velocity Planet Searcher in La Silla, Chile, and ESPRESSO, the Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations in Paranal, Chile. Both instruments, connected to powerful telescopes, measure tiny shifts in the light spectrum of stars, caused by the gravity of planets tugging the star back and forth as they orbit.
But such tiny shifts in the star’s spectrum also can be caused by imposters – spots, flares, or other activity on the star’s surface, carried along as the star rotates and masquerading as orbiting planets. The science team spent years painstakingly analyzing the spectrum shifts, or “radial velocity” data, for any sign of background noise or even jitters from the instruments themselves. They confirmed the reputation of HD 20794 as a fairly quiet star, not prone to outbursts that might be confused for signs of orbiting planets.
Fun Facts
The elliptically orbiting super-Earth appears to be an ideal target for future space-based telescopes designed to search for habitable worlds, seeking possible signs of life. High on the list is NASA’s Habitable Worlds Observatory, which will someday examine the atmospheres of Earth-sized planets around Sun-like stars. When launched in the decades ahead, the observatory would spread the light from such planets into a spectrum to determine which gases are present – including those that might reveal some form of life. The relative closeness of HD 20974, only 20 light-years away, its brightness, and its low level of surface activity – not to mention the third planet’s wild temperature swings – could make this system a prime candidate for scrutiny by HWO.
The Discoverers
The international science team that confirmed the eccentric super-Earth was led by researcher Nicola Nari of the Light Bridges S.L. and the Instituto de Astrofisica de Canarias, and included Dr. Michael Cretignier of the University of Oxford, who first picked up the potential planet’s signal in 2022. Their paper, “Revisiting the multi-planet system of the nearby star HD 20794,” was published online by the journal, Astronomy and Astrophysics, in January 2025.
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By NASA
4 Min Read Science in Orbit: Results Published on Space Station Research in 2024
NASA and its international partners have hosted research experiments and fostered collaboration aboard the International Space Station for over 25 years. More than 4,000 investigations have been conducted, resulting in over 4,400 research publications with 361 in 2024 alone. Space station research continues to advance technology on Earth and prepare for future space exploration missions.
Below is a selection of scientific results that were published over the past year. For more space station research achievements and additional information about the findings mentioned here, check out the 2024 Annual Highlights of Results.
Making stronger cement
NASA’s Microgravity Investigation of Cement Solidification (MICS) observes the hydration reaction and hardening process of cement paste on the space station. As part of this experiment, researchers used artificial intelligence to create 3D models from 2D microscope images of cement samples formed in microgravity. Characteristics such as pore distribution and crystal growth can impact the integrity of any concrete-like material, and these artificial intelligence models allow for predicting internal structures that can only be adequately captured in 3D. Results from the MICS investigation improve researchers’ understanding of cement hardening and could support innovations for civil engineering, construction, and manufacturing of industrial materials on exploration missions.
European Space Agency (ESA) astronaut Alexander Gerst works on the Microgravity Investigation of Cement Solidification (MICS) experiment in a portable glovebag aboard the International Space Station.NASA Creating Ideal Clusters
The JAXA (Japan Aerospace Exploration Agency) Colloidal Clusters investigation uses the attractive forces between oppositely charged particles to form pyramid-shaped clusters. These clusters are a key building block for the diamond lattice, an ideal structure in materials with advanced light-manipulation capabilities. Researchers immobilized clusters on the space station using a holding gel with increased durability. The clusters returned to Earth can scatter light in the visible to near-infrared range used in optical and laser communications systems. By characterizing these clusters, scientists can gain insights into particle aggregation in nature and learn how to effectively control light reflection for technologies that bend light, such as specialized sensors, high-speed computing components, and even novel cloaking devices.
A fluorescent micrograph image shows colloidal clusters immobilized in gel. Negatively charged particles are represented by green fluorescence, and positively charged particles are red. JAXA/ Nagoya City University Controlling Bubble Formation
NASA’s Optical Imaging of Bubble Dynamics on Nanostructured Surfaces studies how different types of surfaces affect bubbles generated by boiling water on the space station. Researchers found that boiling in microgravity generates larger bubbles and that bubbles grow about 30 times faster than on Earth. Results also show that surfaces with finer microstructures generate slower bubble formation due to changes in the rate of heat transfer. Fundamental insights into bubble growth could improve thermal cooling systems and sensors that use bubbles.
High-speed video shows dozens of bubbles growing in microgravity until they collapse.Tengfei Luo Evaluating Cellular Responses to Space
The ESA (European Space Agency) investigation Cytoskeleton attempts to uncover how microgravity impacts important regulatory processes that control cell multiplication, programmed cell death, and gene expression. Researchers cultured a model of human bone cells and identified 24 pathways that are affected by microgravity. Cultures from the space station showed a reduction of cellular expansion and increased activity in pathways associated with inflammation, cell stress, and iron-dependent cell death. These results help to shed light on cellular processes related to aging and the microgravity response, which could feed into the development of future countermeasures to help maintain astronaut health and performance.
Fluorescent staining of cells from microgravity (left) and ground control (right).ESA Improving Spatial Awareness
The CSA (Canadian Space Agency) investigation Wayfinding investigates the impact of long-duration exposure to microgravity on the orientation skills in astronauts. Researchers identified reduced activity in spatial processing regions of the brain after spaceflight, particularly those involved in visual perception and orientation of spatial attention. In microgravity, astronauts cannot process balance cues normally provided by gravity, affecting their ability to perform complex spatial tasks. A better understanding of spatial processes in space allows researchers to find new strategies to improve the work environment and reduce the impact of microgravity on the spatial cognition of astronauts.
An MRI (magnetic resonance imaging) scan of the brain shows activity in the spatial orientation regions.NeuroLab Monitoring low Earth orbit
The Roscomos-ESA-Italian Space Agency investigation Mini-EUSO (Multiwavelength Imaging New Instrument for the Extreme Universe Space Observatory) is a multipurpose telescope designed to examine light emissions entering Earth’s atmosphere. Researchers report that Mini-EUSO data has helped to develop a new machine learning algorithm to detect space debris and meteors that move across the field of view of the telescope. The algorithm showed increased precision for meteor detection and identified characteristics such as rotation rate. The algorithm could be implemented on ground-based telescopes or satellites to identify space debris, meteors, or asteroids and increase the safety of space activities.
The Mini-EUSO telescope is shown in early assembly.JEM-EUSO Program For more space station research achievements and additional information about the findings mentioned here, check out the 2024 Annual Highlights of Results.
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