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By NASA
Honolulu is pictured here beside a calm sea in 2017. A JPL technology recently detected and confirmed a tsunami up to 45 minutes prior to detection by tide gauges in Hawaii, and it estimated the speed of the wave to be over 580 miles per hour (260 meters per second) near the coast.NASA/JPL-Caltech A massive earthquake and subsequent tsunami off Russia in late July tested an experimental detection system that had deployed a critical component just the day before.
A recent tsunami triggered by a magnitude 8.8 earthquake off Russia’s Kamchatka Peninsula sent pressure waves to the upper layer of the atmosphere, NASA scientists have reported. While the tsunami did not wreak widespread damage, it was an early test for a detection system being developed at the agency’s Jet Propulsion Laboratory in Southern California.
Called GUARDIAN (GNSS Upper Atmospheric Real-time Disaster Information and Alert Network), the experimental technology “functioned to its full extent,” said Camille Martire, one of its developers at JPL. The system flagged distortions in the atmosphere and issued notifications to subscribed subject matter experts in as little as 20 minutes after the quake. It confirmed signs of the approaching tsunami about 30 to 40 minutes before waves made landfall in Hawaii and sites across the Pacific on July 29 (local time).
“Those extra minutes of knowing something is coming could make a real difference when it comes to warning communities in the path,” said JPL scientist Siddharth Krishnamoorthy.
Near-real-time outputs from GUARDIAN must be interpreted by experts trained to identify the signs of tsunamis. But already it’s one of the fastest monitoring tools of its kind: Within about 10 minutes of receiving data, it can produce a snapshot of a tsunami’s rumble reaching the upper atmosphere.
The dots in this graph indicate wave disturbances in the ionosphere as measured be-tween ground stations and navigation satellites. The initial spike shows the acoustic wave coming from the epicenter of the July 29 quake that caused the tsunami; the red squiggle shows the gravity wave the tsunami generated.NASA/JPL-Caltech The goal of GUARDIAN is to augment existing early warning systems. A key question after a major undersea earthquake is whether a tsunami was generated. Today, forecasters use seismic data as a proxy to predict if and where a tsunami could occur, and they rely on sea-based instruments to confirm that a tsunami is passing by. Deep-ocean pressure sensors remain the gold standard when it comes to sizing up waves, but they are expensive and sparse in locations.
“NASA’s GUARDIAN can help fill the gaps,” said Christopher Moore, director of the National Oceanic and Atmospheric Administration Center for Tsunami Research. “It provides one more piece of information, one more valuable data point, that can help us determine, yes, we need to make the call to evacuate.”
Moore noted that GUARDIAN adds a unique perspective: It’s able to sense sea surface motion from high above Earth, globally and in near-real-time.
Bill Fry, chair of the United Nations technical working group responsible for tsunami early warning in the Pacific, said GUARDIAN is part of a technological “paradigm shift.” By directly observing ocean dynamics from space, “GUARDIAN is absolutely something that we in the early warning community are looking for to help underpin next generation forecasting.”
How GUARDIAN works
GUARDIAN takes advantage of tsunami physics. During a tsunami, many square miles of the ocean surface can rise and fall nearly in unison. This displaces a significant amount of air above it, sending low-frequency sound and gravity waves speeding upwards toward space. The waves interact with the charged particles of the upper atmosphere — the ionosphere — where they slightly distort the radio signals coming down to scientific ground stations of GPS and other positioning and timing satellites. These satellites are known collectively as the Global Navigation Satellite System (GNSS).
While GNSS processing methods on Earth correct for such distortions, GUARDIAN uses them as clues.
SWOT Satellite Measures Pacific Tsunami The software scours a trove of data transmitted to more than 350 continuously operating GNSS ground stations around the world. It can potentially identify evidence of a tsunami up to about 745 miles (1,200 kilometers) from a given station. In ideal situations, vulnerable coastal communities near a GNSS station could know when a tsunami was heading their way and authorities would have as much as 1 hour and 20 minutes to evacuate the low-lying areas, thereby saving countless lives and property.
Key to this effort is the network of GNSS stations around the world supported by NASA’s Space Geodesy Project and Global GNSS Network, as well as JPL’s Global Differential GPS network that transmits the data in real time.
The Kamchatka event offered a timely case study for GUARDIAN. A day before the quake off Russia’s northeast coast, the team had deployed two new elements that were years in the making: an artificial intelligence to mine signals of interest and an accompanying prototype messaging system.
Both were put to the test when one of the strongest earthquakes ever recorded spawned a tsunami traveling hundreds of miles per hour across the Pacific Ocean. Having been trained to spot the kinds of atmospheric distortions caused by a tsunami, GUARDIAN flagged the signals for human review and notified subscribed subject matter experts.
Notably, tsunamis are most often caused by large undersea earthquakes, but not always. Volcanic eruptions, underwater landslides, and certain weather conditions in some geographic locations can all produce dangerous waves. An advantage of GUARDIAN is that it doesn’t require information on what caused a tsunami; rather, it can detect that one was generated and then can alert the authorities to help minimize the loss of life and property.
While there’s no silver bullet to stop a tsunami from making landfall, “GUARDIAN has real potential to help by providing open access to this data,” said Adrienne Moseley, co-director of the Joint Australian Tsunami Warning Centre. “Tsunamis don’t respect national boundaries. We need to be able to share data around the whole region to be able to make assessments about the threat for all exposed coastlines.”
To learn more about GUARDIAN, visit:
https://guardian.jpl.nasa.gov
News Media Contacts
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
626-379-6874 / 818-354-0307
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
Written by Sally Younger
2025-117
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By NASA
Ames Science Directorate’s Stars of the Month: September 2025
The NASA Ames Science Directorate recognizes the outstanding contributions of (pictured left to right) Taejin Park, Lydia Schweitzer, and Rachel Morgan. Their commitment to the NASA mission represents the entrepreneurial spirit, technical expertise, and collaborative disposition needed to explore this world and beyond.
Earth Science Star: Taejin Park
Taejin Park is a NASA Earth eXchange (NEX) research scientist within the Biospheric Science Branch, for the Bay Area Environmental Research Institute (BAERI). As the Project Scientist for the Wildfire, Ecosystem Resilience, & Risk Assessment (WERK) project, he has exhibited exemplary leadership and teamwork leading to this multi-year study with the California Natural Resources Agency (CNRA) and California Air Resources Board (CARB) to develop tracking tools of statewide ecological condition, disturbance, and recovery efforts related to wildfires.
Space Science and Astrobiology Star: Lydia Schweitzer
Lydia Schweitzer is a research scientist within the Planetary Systems Branch for the Bay Area Environmental Research Institute (BAERI) as a member of the Neutron Spectrometer System (NSS) team with broad contributions in instrumentation, robotic rovers and lunar exploration. Lydia is recognized for her leadership on a collaborative project to design and build a complex interface unit that is crucial for NSS to communicate with the Japanese Space Agency’s Lunar Polar eXploration rover mission (LUPEX). In addition, she is recognized for her role as an instrument scientist for the Volatiles Investigating Polar Exploration Rover (VIPER) and MoonRanger missions.
Space Science and Astrobiology Star: Rachel Morgan
Rachel Morgan is an optical scientist in the Astrophysics Branch for the SETI Institute. As AstroPIC’s lead experimentalist and the driving force behind the recently commissioned photonic testbed at NASA Ames, this month she achieved a record 92 dB on-chip suppression on a single photonic-integrated chip (PIC) output channel. This advances critical coronagraph technology and is a significant milestone relevant to the Habitable Worlds Observatory.
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By NASA
This graphic features data from NASA’s Chandra X-ray Observatory of the Cassiopeia A (Cas A) supernova remnant that reveals that the star’s interior violently rearranged itself mere hours before it exploded. The main panel of this graphic is Chandra data that shows the location of different elements in the remains of the explosion: silicon (represented in red), sulfur (yellow), calcium (green) and iron (purple). The blue color reveals the highest-energy X-ray emission detected by Chandra in Cas A and an expanding blast wave. The inset reveals regions with wide ranges of relative abundances of silicon and neon. This data, plus computer modeling, reveal new insight into how massive stars like Cas A end their lives.X-ray: NASA/CXC/Meiji Univ./T. Sato et al.; Image Processing: NASA/CXC/SAO/N. Wolk The inside of a star turned on itself before it spectacularly exploded, according to a new study from NASA’s Chandra X-ray Observatory. Today, this shattered star, known as the Cassiopeia A supernova remnant, is one of the best-known, well-studied objects in the sky.
Over three hundred years ago, however, it was a giant star on the brink of self-destruction. The new Chandra study reveals that just hours before it exploded, the star’s interior violently rearranged itself. This last-minute shuffling of its stellar belly has profound implications for understanding how massive stars explode and how their remains behave afterwards.
Cassiopeia A (Cas A for short) was one of the first objects the telescope looked at after its launch in 1999, and astronomers have repeatedly returned to observe it.
“It seems like each time we closely look at Chandra data of Cas A, we learn something new and exciting,” said Toshiki Sato of Meiji University in Japan who led the study. “Now we’ve taken that invaluable X-ray data, combined it with powerful computer models, and found something extraordinary.”
As massive stars age, increasingly heavy elements form in their interiors by nuclear reactions, creating onion-like layers of different elements. Their outer layer is mostly made of hydrogen, followed by layers of helium, carbon and progressively heavier elements – extending all the way down to the center of the star.
Once iron starts forming in the core of the star, the game changes. As soon as the iron core grows beyond a certain mass (about 1.4 times the mass of the Sun), it can no longer support its own weight and collapses. The outer part of the star falls onto the collapsing core, and rebounds as a core-collapse supernova.
The new research with Chandra data reveals a change that happened deep within the star at the very last moments of its life. After more than a million years, Cas A underwent major changes in its final hours before exploding.
“Our research shows that just before the star in Cas A collapsed, part of an inner layer with large amounts of silicon traveled outwards and broke into a neighboring layer with lots of neon,” said co-author Kai Matsunaga of Kyoto University in Japan. “This is a violent event where the barrier between these two layers disappears.”
This upheaval not only caused material rich in silicon to travel outwards; it also forced material rich in neon to travel inwards. The team found clear traces of these outward silicon flows and inward neon flows in the remains of Cas A’s supernova remnant. Small regions rich in silicon but poor in neon are located near regions rich in neon and poor in silicon.
The survival of these regions not only provides critical evidence for the star’s upheaval, but also shows that complete mixing of the silicon and neon with other elements did not occur immediately before or after the explosion. This lack of mixing is predicted by detailed computer models of massive stars near the ends of their lives.
There are several significant implications for this inner turmoil inside of the doomed star. First, it may directly explain the lopsided rather than symmetrical shape of the Cas A remnant in three dimensions. Second, a lopsided explosion and debris field may have given a powerful kick to the remaining core of the star, now a neutron star, explaining the high observed speed of this object.
Finally, the strong turbulent flows created by the star’s internal changes may have promoted the development of the supernova blast wave, facilitating the star’s explosion.
“Perhaps the most important effect of this change in the star’s structure is that it may have helped trigger the explosion itself,” said co-author Hiroyuki Uchida, also of Kyoto University. “Such final internal activity of a star may change its fate—whether it will shine as a supernova or not.”
These results have been published in the latest issue of The Astrophysical Journal and are available online.
To learn more about Chandra, visit:
https://science.nasa.gov/chandra
Read more from NASA’s Chandra X-ray Observatory Learn more about the Chandra X-ray Observatory and its mission here:
https://www.nasa.gov/chandra
https://chandra.si.edu
Visual Description
This release features a composite image of Cassiopeia A, a donut-shaped supernova remnant located about 11,000 light-years from Earth. Included in the image is an inset closeup, which highlights a region with relative abundances of silicon and neon.
Over three hundred years ago, Cassiopeia A, or Cas A, was a star on the brink of self-destruction. In composition it resembled an onion with layers rich in different elements such as hydrogen, helium, carbon, silicon, sulfur, calcium, and neon, wrapped around an iron core. When that iron core grew beyond a certain mass, the star could no longer support its own weight. The outer layers fell into the collapsing core, then rebounded as a supernova. This explosion created the donut-like shape shown in the composite image. The shape is somewhat irregular, with the thinner quadrant of the donut to the upper left of the off-center hole.
In the body of the donut, the remains of the star’s elements create a mottled cloud of colors, marbled with red and blue veins. Here, sulfur is represented by yellow, calcium by green, and iron by purple. The red veins are silicon, and the blue veins, which also line the outer edge of the donut-shape, are the highest energy X-rays detected by Chandra and show the explosion’s blast wave.
The inset uses a different color code and highlights a colorful, mottled region at the thinner, upper left quadrant of Cas A. Here, rich pockets of silicon and neon are identified in the red and blue veins, respectively. New evidence from Chandra indicates that in the hours before the star’s collapse, part of a silicon-rich layer traveled outwards, and broke into a neighboring neon-rich layer. This violent breakdown of layers created strong turbulent flows and may have promoted the development of the supernova’s blast wave, facilitating the star’s explosion. Additionally, upheaval in the interior of the star may have produced a lopsided explosion, resulting in the irregular shape, with an off-center hole (and a thinner bite of donut!) at our upper left.
News Media Contact
Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu
Corinne Beckinger
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
corinne.m.beckinger@nasa.gov
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Last Updated Aug 28, 2025 EditorLee MohonContactCorinne M. Beckingercorinne.m.beckinger@nasa.govLocationMarshall Space Flight Center Related Terms
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By NASA
Explore Hubble 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 AI and Hubble Science Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts Multimedia Images Videos Sonifications Podcasts e-Books Online Activities 3D Hubble Models Lithographs Fact Sheets Posters Hubble on the NASA App Glossary News Hubble News Social Media Media Resources More 35th Anniversary Online Activities 2 min read
Hubble Observes Noteworthy Nearby Spiral Galaxy
This NASA/ESA Hubble Space Telescope image features the nearby spiral galaxy NGC 2835. ESA/Hubble & NASA, R. Chandar, J. Lee and the PHANGS-HST team This NASA/ESA Hubble Space Telescope image offers a new view of the nearby spiral galaxy NGC 2835, which lies 35 million light-years away in the constellation Hydra (the Water Snake). The galaxy’s spiral arms are dotted with young blue stars sweeping around an oval-shaped center where older stars reside.
This image differs from previously released images from Hubble and the NASA/ESA/CSA James Webb Space Telescope because it incorporates new data from Hubble that captures a specific wavelength of red light called H-alpha. The regions that are bright in H-alpha emission are visible along NGC 2835’s spiral arms, where dozens of bright pink nebulae appear like flowers in bloom. Astronomers are interested in H-alpha light because it signals the presence of several different types of nebulae that arise during different stages of a star’s life. Newborn, massive stars create nebulae called H II regions that are particularly brilliant sources of H-alpha light, while dying stars can leave behind supernova remnants or planetary nebulae that can also be identified by their H-alpha emission.
By using Hubble’s sensitive instruments to survey 19 nearby galaxies, researchers aim to identify more than 50,000 nebulae. These observations will help to explain how stars affect their birth neighborhoods through intense starlight and winds.
Text Credit: ESA/Hubble
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Last Updated Aug 21, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
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Hubble Space Telescope
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By NASA
Astronaut Victor Glover interacts with an Orion spacecraft simulator during NASA’s “All-Star Shoot for the Stars” event at The Children’s Museum of Indianapolis on Saturday, July 18, 2025. Credit: NASA/Zach Lucas From astronauts to athletes, researchers to referees, and communicators to coaches, NASA is much like basketball – we all train to reach the top of our game. Staff from NASA’s Glenn Research Center in Cleveland drove home this point during the “All-Star Shoot for the Stars” event at The Children’s Museum of Indianapolis, July 17-19. As part of WNBA All-Star Game activities, this event highlighted NASA technology while illuminating the intersection of sports and STEM.
The event offered a captivating look into space exploration, thanks to the combined efforts of NASA and museum staff. Highlights included a detailed Orion exhibit, a new spacesuit display featuring five full-scale spacesuits, and virtual reality demonstrations. Visitors also had the chance to enjoy an interactive spacesuit app and a unique cosmic selfie station.
On Friday, July 18, 2025, visitors at NASA’s “All-Star Shoot for the Stars” event at The Children’s Museum of Indianapolis look at a new spacesuit display featuring five full-scale spacesuits. Credit: NASA/Christopher Richards The event was made even more memorable by Artemis II astronaut Victor Glover, who connected with visitors and posed for photos. WNBA legend Tamika Catchings also made a special appearance, inspiring attendees with a message to “aim high!”
“All Star Weekend presented an excellent opportunity to share NASA’s mission with the Indianapolis community and people across the Midwest who were in town for the game,” said Jan Wittry, Glenn’s news chief. “I saw children’s faces light up as they interacted with the exhibits and talked to NASA experts, sparking a curiosity among our potential future STEM workforce.”
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