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By NASA
NASA/JPL-Caltech/MSSS NASA’s Curiosity Mars rover captured this feather-shaped iridescent cloud just after sunset on Jan. 27, 2023. Studying the colors in iridescent clouds tells scientists something about particle size within the clouds and how they grow over time. These clouds were captured as part of a seasonal imaging campaign to study noctilucent, or “night-shining” clouds. A new campaign in January 2025 led to Curiosity capturing this video of red- and green-tinged clouds drifting through the Martian sky.
Learn more about iridescent twilight clouds on Mars.
Image credit: NASA/JPL-Caltech/MSSS
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Cliffs slope into the ocean in San Simeon, California. All along the state’s dynamic coastline, land is inching down and up due to natural and human-caused factors. A bet-ter understanding of this motion can help communities prepare for rising seas.NASA/JPL-Caltech The elevation changes may seem small — amounting to fractions of inches per year — but they can increase or decrease local flood risk, wave exposure, and saltwater intrusion.
Tracking and predicting sea level rise involves more than measuring the height of our oceans: Land along coastlines also inches up and down in elevation. Using California as a case study, a NASA-led team has shown how seemingly modest vertical land motion could significantly impact local sea levels in coming decades.
By 2050, sea levels in California are expected to increase between 6 and 14.5 feet (15 and 37 centimeters) higher than year 2000 levels. Melting glaciers and ice sheets, as well as warming ocean water, are primarily driving the rise. As coastal communities develop adaptation strategies, they can also benefit from a better understanding of the land’s role, the team said. The findings are being used in updated guidance for the state.
“In many parts of the world, like the reclaimed ground beneath San Francisco, the land is moving down faster than the sea itself is going up,” said lead author Marin Govorcin, a remote sensing scientist at NASA’s Jet Propulsion Laboratory in Southern California.
The new study illustrates how vertical land motion can be unpredictable in scale and speed; it results from both human-caused factors such as groundwater pumping and wastewater injection, as well as from natural ones like tectonic activity. The researchers showed how direct satellite observations can improve estimates of vertical land motion and relative sea level rise. Current models, which are based on tide gauge measurements, cannot cover every location and all the dynamic land motion at work within a given region.
Local Changes
Researchers from JPL and the National Oceanic and Atmospheric Administration (NOAA) used satellite radar to track more than a thousand miles of California coast rising and sinking in new detail. They pinpointed hot spots — including cities, beaches, and aquifers — at greater exposure to rising seas now and in coming decades.
To capture localized motion inch by inch from space, the team analyzed radar measurements made by ESA’s (the European Space Agency’s) Sentinel-1 satellites, as well as motion velocity data from ground-based receiving stations in the Global Navigation Satellite System. Researchers compared multiple observations of the same locations made between 2015 to 2023 using a processing technique called interferometric synthetic aperture radar (InSAR).
Scientists mapped land sinking (indicated in blue) in coastal California cities and in parts of the Central Valley due to factors like soil compaction, erosion, and groundwater withdrawal. They also tracked uplift hot spots (shown in red), including in Long Beach, a site of oil and gas production. NASA Earth Observatory Homing in on the San Francisco Bay Area — specifically, San Rafael, Corte Madera, Foster City, and Bay Farm Island — the team found the land subsiding at a steady rate of more than 0.4 inches (10 millimeters) per year due largely to sediment compaction. Accounting for this subsidence in the lowest-lying parts of these areas, local sea levels could rise more than 17 inches (45 centimeters) by 2050. That’s more than double the regional estimate of 7.4 inches (19 centimeters) based solely on tide gauge projections.
Not all coastal locations in California are sinking. The researchers mapped uplift hot spots of several millimeters per year in the Santa Barbara groundwater basin, which has been steadily replenishing since 2018. They also observed uplift in Long Beach, where fluid extraction and injection occur with oil and gas production.
The scientists further calculated how human-induced drivers of local land motion increase uncertainties in the sea level projections by up to 15 inches (40 centimeters) in parts of Los Angeles and San Diego counties. Reliable projections in these areas are challenging because the unpredictable nature of human activities, such as hydrocarbon production and groundwater extraction, necessitating ongoing monitoring of land motion.
Fluctuating Aquifers, Slow-Moving Landslides
In the middle of California, in the fast-sinking parts of the Central Valley (subsiding as much as 8 inches, or 20 centimeters, per year), land motion is influenced by groundwater withdrawal. Periods of drought and precipitation can alternately draw down or inflate underground aquifers. Such fluctuations were also observed over aquifers in Santa Clara in the San Francisco Bay Area, Santa Ana in Orange County, and Chula Vista in San Diego County.
Along rugged coastal terrain like the Big Sur mountains below San Francisco and Palos Verdes Peninsula in Los Angeles, the team pinpointed local zones of downward motion associated with slow-moving landslides. In Northern California they also found sinking trends at marshlands and lagoons around San Francisco and Monterey bays, and in Sonoma County’s Russian River estuary. Erosion in these areas likely played a key factor.
Scientists, decision-makers, and the public can monitor these and other changes occurring via the JPL-led OPERA (Observational Products for End-Users from Remote Sensing Analysis) project. The OPERA project details land surface elevational changes across North America, shedding light on dynamic processes including subsidence, tectonics, and landslides.
The OPERA project will leverage additional state-of-the-art InSAR data from the upcoming NISAR (NASA-Indian Space Research Organization Synthetic Aperture Radar) mission, expected to launch within the coming months.
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Jane J. Lee / Andrew Wang
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Last Updated Feb 10, 2025 Related Terms
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2 min read Newly Minted Ph.D. Studies Phytoplankton with NASA’s FjordPhyto Project
FjordPhyto is a collective effort where travelers on tour expedition vessels in Antarctica help scientists…
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By NASA
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February’s Night Sky Notes: How Can You Help Curb Light Pollution?
Light pollution has long troubled astronomers, who generally shy away from deep sky observing under full Moon skies. The natural light from a bright Moon floods the sky and hides views of the Milky Way, dim galaxies and nebula, and shooting stars. In recent years, human-made light pollution has dramatically surpassed the interference of even a bright full Moon, and its effects are now noticeable to a great many people outside of the astronomical community. Harsh, bright white LED streetlights, while often more efficient and long-lasting, often create unexpected problems for communities replacing their old street lamps. Some notable concerns are increased glare and light trespass, less restful sleep, and disturbed nocturnal wildlife patterns. There is increasing awareness of just how much light is too much light at night. You don’t need to give in to despair over encroaching light pollution; you can join efforts to measure it, educate others, and even help stop or reduce the effects of light pollution in your community.
Before and after pictures of replacement lighting at the 6th Street Bridge over the Los Angeles River. The second picture shows improvements in some aspects of light pollution, as light is not directed to the sides and upwards from the upgraded fixtures, reducing skyglow. However, it also shows the use of brighter, whiter LEDs, which is not generally ideal, along with increased light bounce back from the road. City of Los Angeles Amateur astronomers and potential citizen scientists around the globe are invited to participate in the Globe at Night (GaN) program to measure light pollution. Measurements are taken by volunteers on a few scheduled days every month and submitted to their database to help create a comprehensive map of light pollution and its change over time. GaN volunteers can take and submit measurements using multiple methods ranging from low-tech naked-eye observations to high-tech sensors and smartphone apps.
Globe at Night citizen scientists can use the following methods to measure light pollution and submit their results:
Their own smartphone camera and dedicated app Manually measure light pollution using their own eyes and detailed charts of the constellations A dedicated light pollution measurement device called a Sky Quality Meter (SQM). The free GaN web app from any internet-connected device (which can also be used to submit their measurements from an SQM or printed-out star charts) Night Sky Network members joined a telecon with Connie Walker of Globe at Night in 2014 and had a lively discussion about the program’s history and how they can participate. The audio of the telecon, transcript, and links to additional resources can be found on their dedicated resource page.
Light pollution has been visible from space for a long time, but new LED lights are bright enough that they stand out from older street lights, even from orbit. The above photo was taken by astronaut Samantha Cristoforetti from the ISS cupola in 2015. The newly installed white LED lights in the center of the city of Milan are noticeably brighter than the lights in the surrounding neighborhoods. NASA/ESA DarkSky International has long been a champion in the fight against light pollution and a proponent of smart lighting design and policy. Their website (at darksky.org) provides many resources for amateur astronomers and other like-minded people to help communities understand the negative impacts of light pollution and how smart lighting policies can not only help bring the stars back to their night skies but make their streets safer by using smarter lighting with less glare. Communities and individuals find that their nighttime lighting choices can help save considerable sums of money when they decide to light their streets and homes “smarter, not brighter” with shielded, directional lighting, motion detectors, timers, and even choosing the proper “temperature” of new LED light replacements to avoid the harsh “pure white” glare that many new streetlamps possess. Their pages on community advocacy and on how to choose dark-sky-friendly lighting are extremely helpful and full of great information. There are even local chapters of the IDA in many communities made up of passionate advocates of dark skies.
DarkSky International has notably helped usher in “Dark Sky Places“, areas around the world that are protected from light pollution. “Dark Sky Parks“, in particular, provide visitors with incredible views of the Milky Way and are perfect places to spot the wonders of a meteor shower. These parks also perform a very important function, showing the public the wonders of a truly dark sky to many people who may have never before even seen a handful of stars in the sky, let alone the full, glorious spread of the Milky Way.
More research into the negative effects of light pollution on the health of humans and the environment is being conducted than ever before. Watching the nighttime light slowly increase in your neighborhood, combined with reading so much bad news, can indeed be disheartening! However, as awareness of light pollution and its negative effects increases, more people are becoming aware of the problem and want to be part of the solution. There is even an episode of PBS Kid’s SciGirls where the main characters help mitigate light pollution in their neighborhood!
Astronomy clubs are uniquely situated to help spread awareness of good lighting practices in their local communities in order to help mitigate light pollution. Take inspiration from Tucson, Arizona, and other dark sky-friendly communities that have adopted good lighting practices. Tucson even reduced its skyglow by 7% after its own citywide lighting conversion, proof that communities can bring the stars back with smart lighting choices.
Originally posted by Dave Prosper: November 2018
Last Updated by Kat Troche: January 2025
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By NASA
NASA’s SPHEREx space observatory was photographed at BAE Systems in Boulder, Colorado, in November 2024 after completing environmental testing. The spacecraft’s three concentric cones help direct heat and light away from the telescope and other components, keeping them cool. Credit: BAE Systems NASA will host a news conference at 12 p.m. EST Friday, Jan. 31, to discuss a new telescope that will improve our understanding of how the universe evolved and search for key ingredients for life in our galaxy.
Agency experts will preview NASA’s SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) mission, which will help scientists better understand the structure of the universe, how galaxies form and evolve, and the origins and abundance of water. Launch is targeted for no earlier than Thursday, Feb. 27.
The news conference will be hosted at the agency’s Jet Propulsion Laboratory in Southern California. Watch live on NASA+, as well as JPL’s X and YouTube channels. Learn how to watch NASA content through a variety of platforms, including social media.
Laurie Leshin, director, NASA JPL, will provide opening remarks. Additional briefing participants include:
Shawn Domagal-Goldman, acting director, Astrophysics Division, NASA Headquarters James Fanson, project manager, SPHEREx, NASA JPL Beth Fabinsky, deputy project manager, SPHEREx, NASA JPL Jamie Bock, principal investigator, SPHEREx, Caltech Cesar Marin, SPHEREx integration engineer, Launch Services Program, NASA’s Kennedy Space Center in Florida To ask questions by phone, members of the media must RSVP no later than two hours before the start of the event to: rexana.v.vizza@jpl.nasa.gov. NASA’s media accreditation policy is available online. Questions also can be asked on social media during the briefing using #AskNASA.
The SPHEREx observatory will survey the entire celestial sky in near-infrared light to help answer cosmic questions involving the birth of the universe, and the subsequent development of galaxies. It also will search for ices of water and organic molecules — essentials for life as we know it — in regions where stars are born from gas and dust, as well as disks around stars where new planets could be forming. Astronomers will use the mission to gather data on more than 450 million galaxies, as well as more than 100 million stars in our own Milky Way galaxy.
The space observatory will share its ride on a SpaceX Falcon 9 rocket with NASA’s PUNCH (Polarimeter to Unify the Corona and Heliosphere) mission, which will lift off from Launch Complex 4E at Vandenberg Space Force Base in Central California.
The SPHEREx mission is managed by NASA JPL for the agency’s Astrophysics Division within the Science Mission Directorate at NASA Headquarters in Washington. The principal investigator is based at Caltech in Pasadena, California, which manages NASA JPL for the agency.
The spacecraft is supplied by BAE Systems. The Korea Astronomy and Space Science Institute contributed the non-flight cryogenic test chamber. Mission data will be publicly available through IPAC at Caltech.
For more information about the mission, visit:
https://nasa.gov/spherex
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Alise Fisher
Headquarters, Washington
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alise.m.fisher@nasa.gov
Val Gratias / Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
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valerie.m.gratias@jpl.nasa.gov / calla.e.cofield@jpl.nasa.gov
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Last Updated Jan 27, 2025 EditorJessica TaveauLocationNASA Headquarters Related Terms
SPHEREx (Spectro-Photometer for the History of the Universe and Ices Explorer) Astrophysics Division Jet Propulsion Laboratory Polarimeter to Unify the Corona and Heliosphere (PUNCH) Science Mission Directorate View the full article
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By NASA
Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More 35th Anniversary 6 Min Read NASA’s Hubble Traces Hidden History of Andromeda Galaxy
This photomosaic of the Andromeda galaxy is the largest ever assembled from Hubble observations. Credits:
NASA, ESA, Benjamin F. Williams (UWashington), Zhuo Chen (UWashington), L. Clifton Johnson (Northwestern); Image Processing: Joseph DePasquale (STScI) In the years following the launch of NASA’s Hubble Space Telescope, astronomers have tallied over 1 trillion galaxies in the universe. But only one galaxy stands out as the most important nearby stellar island to our Milky Way — the magnificent Andromeda galaxy (Messier 31). It can be seen with the naked eye on a very clear autumn night as a faint cigar-shaped object roughly the apparent angular diameter of our Moon.
A century ago, Edwin Hubble first established that this so-called “spiral nebula” was actually very far outside our own Milky Way galaxy — at a distance of approximately 2.5 million light-years or roughly 25 Milky Way diameters. Prior to that, astronomers had long thought that the Milky way encompassed the entire universe. Overnight, Hubble’s discovery turned cosmology upside down by unveiling an infinitely grander universe.
Now, a century later, the space telescope named for Hubble has accomplished the most comprehensive survey of this enticing empire of stars. The Hubble telescope is yielding new clues to the evolutionary history of Andromeda, and it looks markedly different from the Milky Way’s history.
This is largest photomosaic ever assembled from Hubble Space Telescope observations. It is a panoramic view of the neighboring Andromeda galaxy, located 2.5 million light-years away. It took over 10 years to make this vast and colorful portrait of the galaxy, requiring over 600 Hubble overlapping snapshots that were challenging to stitch together. The galaxy is so close to us, that in angular size it is six times the apparent diameter of the full Moon, and can be seen with the unaided eye. For Hubble’s pinpoint view, that’s a lot of celestial real estate to cover. This stunning, colorful mosaic captures the glow of 200 million stars. That’s still a fraction of Andromeda’s population. And the stars are spread across about 2.5 billion pixels. The detailed look at the resolved stars will help astronomers piece together the galaxy’s past history that includes mergers with smaller satellite galaxies. NASA, ESA, Benjamin F. Williams (UWashington), Zhuo Chen (UWashington), L. Clifton Johnson (Northwestern); Image Processing: Joseph DePasquale (STScI)
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Without Andromeda as a proxy for spiral galaxies in the universe at large, astronomers would know much less about the structure and evolution of our own Milky Way. That’s because we are embedded inside the Milky Way. This is like trying to understand the layout of New York City by standing in the middle of Central Park.
“With Hubble we can get into enormous detail about what’s happening on a holistic scale across the entire disk of the galaxy. You can’t do that with any other large galaxy,” said principal investigator Ben Williams of the University of Washington. Hubble’s sharp imaging capabilities can resolve more than 200 million stars in the Andromeda galaxy, detecting only stars brighter than our Sun. They look like grains of sand across the beach. But that’s just the tip of the iceberg. Andromeda’s total population is estimated to be 1 trillion stars, with many less massive stars falling below Hubble’s sensitivity limit.
Photographing Andromeda was a herculean task because the galaxy is a much bigger target on the sky than the galaxies Hubble routinely observes, which are often billions of light-years away. The full mosaic was carried out under two Hubble programs. In total, it required over 1,000 Hubble orbits, spanning more than a decade.
This panorama started with the Panchromatic Hubble Andromeda Treasury (PHAT) program about a decade ago. Images were obtained at near-ultraviolet, visible, and near-infrared wavelengths using the Advanced Camera for Surveys and the Wide Field Camera 3 aboard Hubble to photograph the northern half of Andromeda.
This is the largest photomosaic ever made by the Hubble Space Telescope. The target is the vast Andromeda galaxy that is only 2.5 million light-years from Earth, making it the nearest galaxy to our own Milky Way. Andromeda is seen almost edge-on, tilted by 77 degrees relative to Earth’s view. The galaxy is so large that the mosaic is assembled from approximately 600 separate overlapping fields of view taken over 10 years of Hubble observing — a challenge to stitch together over such a large area. The mosaic image is made up of at least 2.5 billion pixels. Hubble resolves an estimated 200 million stars that are hotter than our Sun, but still a fraction of the galaxy’s total estimated stellar population. Interesting regions include: (a) Clusters of bright blue stars embedded within the galaxy, background galaxies seen much farther away, and photo-bombing by a couple bright foreground stars that are actually inside our Milky Way; (b) NGC 206 the most conspicuous star cloud in Andromeda; (c) A young cluster of blue newborn stars; (d) The satellite galaxy M32, that may be the residual core of a galaxy that once collided with Andromeda; (e) Dark dust lanes across myriad stars.
NASA, ESA, Benjamin F. Williams (UWashington), Zhuo Chen (UWashington), L. Clifton Johnson (Northwestern); Image Processing: Joseph DePasquale (STScI)
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This program was followed up by the Panchromatic Hubble Andromeda Southern Treasury (PHAST), recently published in The Astrophysical Journal and led by Zhuo Chen at the University of Washington, which added images of approximately 100 million stars in the southern half of Andromeda. This region is structurally unique and more sensitive to the galaxy’s merger history than the northern disk mapped by the PHAT survey.
The combined programs collectively cover the entire disk of Andromeda, which is seen almost edge-on — tilted by 77 degrees relative to Earth’s view. The galaxy is so large that the mosaic is assembled from approximately 600 separate fields of view. The mosaic image is made up of at least 2.5 billion pixels.
The complementary Hubble survey programs provide information about the age, heavy-element abundance, and stellar masses inside Andromeda. This will allow astronomers to distinguish between competing scenarios where Andromeda merged with one or more galaxies. Hubble’s detailed measurements constrain models of Andromeda’s merger history and disk evolution.
A Galactic ‘Train Wreck’
Though the Milky Way and Andromeda formed presumably around the same time many billions of years ago, observational evidence shows that they have very different evolutionary histories, despite growing up in the same cosmological neighborhood. Andromeda seems to be more highly populated with younger stars and unusual features like coherent streams of stars, say researchers. This implies it has a more active recent star-formation and interaction history than the Milky Way.
“Andromeda’s a train wreck. It looks like it has been through some kind of event that caused it to form a lot of stars and then just shut down,” said Daniel Weisz at the University of California, Berkeley. “This was probably due to a collision with another galaxy in the neighborhood.”
A possible culprit is the compact satellite galaxy Messier 32, which resembles the stripped-down core of a once-spiral galaxy that may have interacted with Andromeda in the past. Computer simulations suggest that when a close encounter with another galaxy uses up all the available interstellar gas, star formation subsides.
The Andromeda Galaxy, our closest galactic neighbor, holds over 1 trillion stars and has been a key to unlocking the secrets of the universe. Thanks to NASA’s Hubble Space Telescope, we’re now seeing Andromeda in stunning new detail, revealing its dynamic history and unique structure.
Credit: NASA’s Goddard Space Flight Center; Lead Producer: Paul Morris
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“Andromeda looks like a transitional type of galaxy that’s between a star-forming spiral and a sort of elliptical galaxy dominated by aging red stars,” said Weisz. “We can tell it’s got this big central bulge of older stars and a star-forming disk that’s not as active as you might expect given the galaxy’s mass.”
“This detailed look at the resolved stars will help us to piece together the galaxy’s past merger and interaction history,” added Williams.
Hubble’s new findings will support future observations by NASA’s James Webb Space Telescope and the upcoming Nancy Grace Roman Space Telescope. Essentially a wide-angle version of Hubble (with the same sized mirror), Roman will capture the equivalent of at least 100 high-resolution Hubble images in a single exposure. These observations will complement and extend Hubble’s huge dataset.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Explore More
Explore the Night Sky: Messier 31
Hubble’s High-Definition Panoramic View of the Andromeda Galaxy
NASA’s Hubble Finds Giant Halo Around the Andromeda Galaxy
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
Ray Villard
Space Telescope Science Institute, Baltimore, MD
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Last Updated Jan 16, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
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