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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 USH
3I/ATLAS as an interstellar visitor, discovered on July 1. Estimated to be up to 15 miles (24 kilometers) wide, it’s barreling toward the Sun at over 130,000 mph. Fortunately, it won’t come closer to Earth than 1.6 astronomical units — about 150 million miles (240 million kilometers) according to NASA.
NASA insists there's no reason for concern — it’s just a comet, end of story. But here's where things get interesting: 3I/ATLAS is the third known interstellar object to enter our solar system, following the enigmatic ‘Oumuamua in 2017 and comet Borisov in 2019. And like those two, it behaves in ways that deviate from what we expect of natural comets.
A newly published paper on the preprint server arXiv (July 16) challenges NASA’s official explanation. The study, co-authored by three scientists, including Harvard astrophysicist Avi Loeb, suggests that 3I/ATLAS might not be a comet at all. Instead, the team proposes it could be an artificial object: a surveillance probe sent by an unknown extraterrestrial intelligence, possibly even one with hostile intent.
Loeb, warns that if this hypothesis turns out to be accurate, the consequences for humanity could be profound. He suggests that preparing defensive countermeasures might be necessary if this object poses a real threat.
What makes 3I/ATLAS so unusual?
According to Loeb, the object’s trajectory is so rare that the odds of a natural comet following the same path are less than 0.005%.
It will pass unusually close to three planets — Venus, Mars, and Jupiter — raising further suspicion.
Most telling of all: 3I/ATLAS lacks a coma, the cloud of gas and dust that typically surrounds comets.
"When analyzed with an open mind, the data offers compelling evidence that 3I/ATLAS may be technological in nature," Loeb explained.
In fact, Loeb outlines eight specific reasons why this object likely isn't a natural interstellar visitor — and why it may be of artificial origin. (You can read his full breakdown (here).
The idea that this mysterious object might be an alien craft, possibly one preparing for closer contact with Earth, is unsettling to say the least. For now, we can only wait, watch... and wonder. View the full article
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By NASA
7 min read
NASA’s Parker Solar Probe Snaps Closest-Ever Images to Sun
KEY POINTS
NASA’s Parker Solar Probe has taken the closest ever images to the Sun, captured just 3.8 million miles from the solar surface. The new close-up images show features in the solar wind, the constant stream of electrically charged subatomic particles released by the Sun that rage across the solar system at speeds exceeding 1 million miles an hour. These images, and other data, are helping scientists understand the mysteries of the solar wind, which is essential to understanding its effects at Earth. On its record-breaking pass by the Sun late last year, NASA’s Parker Solar Probe captured stunning new images from within the Sun’s atmosphere. These newly released images — taken closer to the Sun than we’ve ever been before — are helping scientists better understand the Sun’s influence across the solar system, including events that can affect Earth.
“Parker Solar Probe has once again transported us into the dynamic atmosphere of our closest star,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters in Washington. “We are witnessing where space weather threats to Earth begin, with our eyes, not just with models. This new data will help us vastly improve our space weather predictions to ensure the safety of our astronauts and the protection of our technology here on Earth and throughout the solar system.”
Parker Solar Probe started its closest approach to the Sun on Dec. 24, 2024, flying just 3.8 million miles from the solar surface. As it skimmed through the Sun’s outer atmosphere, called the corona, in the days around the perihelion, it collected data with an array of scientific instruments, including the Wide-Field Imager for Solar Probe, or WISPR.
Parker Solar Probe has revolutionized our understanding of the solar wind thanks to the spacecraft’s many passes through the Sun’s outer atmosphere.
Credit: NASA’s Goddard Space Flight Center/Joy Ng The new WISPR images reveal the corona and solar wind, a constant stream of electrically charged particles from the Sun that rage across the solar system. The solar wind expands throughout of the solar system with wide-ranging effects. Together with outbursts of material and magnetic currents from the Sun, it helps generate auroras, strip planetary atmospheres, and induce electric currents that can overwhelm power grids and affect communications at Earth. Understanding the impact of solar wind starts with understanding its origins at the Sun.
The WISPR images give scientists a closer look at what happens to the solar wind shortly after it is released from the corona. The images show the important boundary where the Sun’s magnetic field direction switches from northward to southward, called the heliospheric current sheet. It also captures the collision of multiple coronal mass ejections, or CMEs — large outbursts of charged particles that are a key driver of space weather — for the first time in high resolution.
“In these images, we’re seeing the CMEs basically piling up on top of one another,” said Angelos Vourlidas, the WISPR instrument scientist at the Johns Hopkins Applied Physics Laboratory, which designed, built, and operates the spacecraft in Laurel, Maryland. “We’re using this to figure out how the CMEs merge together, which can be important for space weather.”
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This video, made from images taken by Parker Solar Probe’s WISPR instrument during its record-breaking flyby of the Sun on Dec. 25, 2024, shows the solar wind racing out from the Sun’s outer atmosphere, the corona. NASA/Johns Hopkins APL/Naval Research Lab When CMEs collide, their trajectory can change, making it harder to predict where they’ll end up. Their merger can also accelerate charged particles and mix magnetic fields, which makes the CMEs’ effects potentially more dangerous to astronauts and satellites in space and technology on the ground. Parker Solar Probe’s close-up view helps scientists better prepare for such space weather effects at Earth and beyond.
Zooming in on Solar Wind’s Origins
The solar wind was first theorized by preeminent heliophysicist Eugene Parker in 1958. His theories about the solar wind, which were met with criticism at the time, revolutionized how we see our solar system. Prior to Parker Solar Probe’s launch in 2018, NASA and its international partners led missions like Mariner 2, Helios, Ulysses, Wind, and ACE that helped scientists understand the origins of the solar wind — but from a distance. Parker Solar Probe, named in honor of the late scientist, is filling in the gaps of our understanding much closer to the Sun.
At Earth, the solar wind is mostly a consistent breeze, but Parker Solar Probe found it’s anything but at the Sun. When the spacecraft reached within 14.7 million miles from the Sun, it encountered zig-zagging magnetic fields — a feature known as switchbacks. Using Parker Solar Probe’s data, scientists discovered that these switchbacks, which came in clumps, were more common than expected.
When Parker Solar Probe first crossed into the corona about 8 million miles from the Sun’s surface in 2021, it noticed the boundary of the corona was uneven and more complex than previously thought.
As it got even closer, Parker Solar Probe helped scientists pinpoint the origin of switchbacks at patches on the visible surface of the Sun where magnetic funnels form. In 2024 scientists announced that the fast solar wind — one of two main classes of the solar wind — is in part powered by these switchbacks, adding to a 50-year-old mystery.
However, it would take a closer view to understand the slow solar wind, which travels at just 220 miles per second, half the speed of the fast solar wind.
“The big unknown has been: how is the solar wind generated, and how does it manage to escape the Sun’s immense gravitational pull?” said Nour Rawafi, the project scientist for Parker Solar Probe at the Johns Hopkins Applied Physics Laboratory. “Understanding this continuous flow of particles, particularly the slow solar wind, is a major challenge, especially given the diversity in the properties of these streams — but with Parker Solar Probe, we’re closer than ever to uncovering their origins and how they evolve.”
Understanding Slow Solar Wind
The slow solar wind, which is twice as dense and more variable than fast solar wind, is important to study because its interplay with the fast solar wind can create moderately strong solar storm conditions at Earth sometimes rivaling those from CMEs.
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This artist’s concept shows a representative state of Earth’s magnetic bubble immersed in the slow solar wind, which averages some 180 to 300 miles per second. NASA’s Goddard Space Flight Center Conceptual Image Lab Prior to Parker Solar Probe, distant observations suggested there are actually two varieties of slow solar wind, distinguished by the orientation or variability of their magnetic fields. One type of slow solar wind, called Alfvénic, has small-scale switchbacks. The second type, called non-Alfvénic, doesn’t show these variations in its magnetic field.
As it spiraled closer to the Sun, Parker Solar Probe confirmed there are indeed two types. Its close-up views are also helping scientists differentiate the origins of the two types, which scientists believe are unique. The non-Alfvénic wind may come off features called helmet streamers — large loops connecting active regions where some particles can heat up enough to escape — whereas Alfvénic wind might originate near coronal holes, or dark, cool regions in the corona.
In its current orbit, bringing the spacecraft just 3.8 million miles from the Sun, Parker Solar Probe will continue to gather additional data during its upcoming passes through the corona to help scientists confirm the slow solar wind’s origins. The next pass comes Sept. 15, 2025.
“We don’t have a final consensus yet, but we have a whole lot of new intriguing data,” said Adam Szabo, Parker Solar Probe mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
By Mara Johnson-Groh
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Jul 10, 2025 Related Terms
Heliophysics Goddard Space Flight Center Heliophysics Division Missions NASA Centers & Facilities NASA Directorates Parker Solar Probe (PSP) Science & Research Science Mission Directorate Solar Wind Space Weather Explore More
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