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Massive Blackout in Spain and Portugal: A harbinger to a black swan event?
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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Written by Michael Allen
An international team of astronomers using NASA’s IXPE (Imaging X-ray Polarimetry Explorer), has challenged our understanding of what happens to matter in the direct vicinity of a black hole.
With IXPE, astronomers can study incoming X-rays and measure the polarization, a property of light that describes the direction of its electric field.
The polarization degree is a measurement of how aligned those vibrations are to each other. Scientists can use a black hole’s polarization degree to determine the location of the corona – a region of extremely hot, magnetized plasma that surrounds a black hole – and how it generates X-rays.
This illustration of material swirling around a black hole highlights a particular feature, called the “corona,” that shines brightly in X-ray light. In this depiction, the corona can be seen as a purple haze floating above the underlying accretion disk, and extending slightly inside of its inner edge. The material within the inner accretion disk is incredibly hot and would glow with a blinding blue-white light, but here has been reduced in brightness to make the corona stand out with better contrast. Its purple color is purely illustrative, standing in for the X-ray glow that would not be obvious in visible light. The warp in the disk is a realistic representation of how the black hole’s immense gravity acts like an optical lens, distorting our view of the flat disk that encircles it. NASA/Caltech-IPAC/Robert Hurt In April, astronomers used IXPE to measure a 9.1% polarization degree for black hole IGR J17091-3624, much higher than they expected based on theoretical models.
“The black hole IGR J17091-3624 is an extraordinary source which dims and brightens with the likeness of a heartbeat, and NASA’s IXPE allowed us to measure this unique source in a brand-new way.” said Melissa Ewing, the lead of the study based at Newcastle University in Newcastle upon Tyne, England.
In X-ray binary systems, an extremely dense object, like a black hole, pulls matter from a nearby source, most often a neighboring star. This matter can begin to swirl around, flattening into a rotating structure known as an accretion disc.
The corona, which lies in the inner region of this accretion disc, can reach extreme temperatures up to 1.8 billion degrees Fahrenheit and radiate very luminous X-rays. These ultra-hot coronas are responsible for some of the brightest X-ray sources in the sky.
Despite how bright the corona is in IGRJ17091-364, at some 28,000 light-years from Earth, it remains far too small and distant for astronomers to capture an image of it.
“Typically, a high polarization degree corresponds with a very edge-on view of the corona. The corona would have to be perfectly shaped and viewed at just the right angle to achieve such a measurement,” said Giorgio Matt, professor at the University of Roma Tre in Italy and a co-author on this paper. “The dimming pattern has yet to be explained by scientists and could hold the keys to understanding this category of black holes.”
The stellar companion of this black hole isn’t bright enough for astronomers to directly estimate the system’s viewing angle, but the unusual changes in brightness observed by IXPE suggest that the edge of the accretion disk was directly facing Earth.
The researchers explored different avenues to explain the high polarization degree.
In one model, astronomers included a “wind” of matter lifted from the accretion disc and launched away from the system, a rarely seen phenomenon. If X-rays from the corona were to meet this matter on their way to IXPE, Compton scattering would occur, leading to these measurements.
Fast Facts
Polarization measurements from IXPE carry information about the orientation and alignment of emitted X-ray light waves. The high the degree of polarization, the more the X-ray waves are traveling in sync. Most polarization in the corona come from a process known as Compton scattering, where light from the accretion disc bounces off the hot plasma of the corona, gaining energy and aligning to vibrate in the same direction. “These winds are one of the most critical missing pieces to understand the growth of all types of black holes,” said Maxime Parra, who led the observation and works on this topic at Ehime University in Matsuyama, Japan. “Astronomers could expect future observations to yield even more surprising polarization degree measurements.”
Another model assumed the plasma in the corona could exhibit a very fast outflow. If the plasma were to be streaming outwards at speeds as high as 20% the speed of light, or roughly 124 million miles per hour, relativistic effects could boost the observed polarization.
In both cases, the simulations could recreate the observed polarization without a very specific edge-on view. Researchers will continue to model and test their predictions to better understand the high polarization degree for future research efforts.
More about IXPE
IXPE, which continues to provide unprecedented data enabling groundbreaking discoveries about celestial objects across the universe, is a joint NASA and Italian Space Agency mission with partners and science collaborators in 12 countries. IXPE is led by NASA’s Marshall Space Flight Center in Huntsville, Alabama. BAE Systems, Inc., headquartered in Falls Church, Virginia, manages spacecraft operations together with the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder.
Learn more about IXPE’s ongoing mission here:
https://www.nasa.gov/ixpe
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Last Updated Aug 12, 2025 EditorBeth RidgewayContactCorinne Edmistoncorinne.m.edmiston@nasa.govLocationMarshall Space Flight Center Related Terms
IXPE (Imaging X-ray Polarimetry Explorer) Marshall Astrophysics Marshall Science Research & Projects Marshall Space Flight Center Explore More
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Learn more about IMBHs and what studying them can tell us about the universe.
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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The SWOT satellite caught the leading edge of the tsunami wave (red) that rolled through the Pacific Ocean on July 30. Sea level data, shown in the highlighted swath, is plotted against a NOAA tsunami forecast model in the background. A red star marks the location of the earthquake that spawned the tsunami.NASA/JPL-Caltech Data provided by the water satellite, a joint effort between NASA and the French space agency, is helping to improve tsunami forecast models, benefitting coastal communities.
The SWOT (Surface Water and Ocean Topography) satellite captured the tsunami spawned by an 8.8 magnitude earthquake off the coast of Russia’s Kamchatka Peninsula on July 30, 11:25 a.m. local time. The satellite, a joint effort between NASA and the French space agency CNES (Centre National d’Études Spatiales), recorded the tsunami about 70 minutes after the earthquake struck.
Disturbances like an earthquake or underwater landslide trigger a tsunami when the event is large enough to displace the entire column of seawater from the ocean floor to the surface. This results in waves that ripple out from the disturbance much like dropping a pebble into a pond generates a series of waves.
“The power of SWOT’s broad, paintbrush-like strokes over the ocean is in providing crucial real-world validation, unlocking new physics, and marking a leap towards more accurate early warnings and safer futures,” said Nadya Vinogradova Shiffer, NASA Earth lead and SWOT program scientist at NASA Headquarters in Washington.
This visualization depicts the leading edge of the tsunami based on sea surface height data from SWOT looking from south to north, when the leading edge was more than 1.5 feet (45 centimeters) east of Japan in the Pacific Ocean.NASA/JPL-Caltech Data from SWOT provided a multidimensional look at the leading edge of the tsunami wave triggered by the Kamchatka earthquake. The measurements included a wave height exceeding 1.5 feet (45 centimeters), shown in red in the highlighted track, as well as a look at the shape and direction of travel of the leading edge of the tsunami. The SWOT data, shown in the highlighted swath running from the southwest to the northeast in the visual, is plotted against a forecast model of the tsunami produced by the U.S. National Oceanic and Atmospheric Administration (NOAA) Center for Tsunami Research. Comparing the observations from SWOT to the model helps forecasters validate their model, ensuring its accuracy.
“A 1.5-foot-tall wave might not seem like much, but tsunamis are waves that extend from the seafloor to the ocean’s surface,” said Ben Hamlington, an oceanographer at NASA’s Jet Propulsion Laboratory in Southern California. “What might only be a foot or two in the open ocean can become a 30-foot wave in shallower water at the coast.”
The tsunami measurements SWOT collected are helping scientists at NOAA’s Center for Tsunami Research improve their tsunami forecast model. Based on outputs from that model, NOAA sends out alerts to coastal communities potentially in the path of a tsunami. The model uses a set of earthquake-tsunami scenarios based on past observations as well as real-time observations from sensors in the ocean.
The SWOT data on the height, shape, and direction of the tsunami wave is key to improving these types of forecast models. “The satellite observations help researchers to better reverse engineer the cause of a tsunami, and in this case, they also showed us that NOAA’s tsunami forecast was right on the money,” said Josh Willis, a JPL oceanographer.
The NOAA Center for Tsunami Research tested their model with SWOT’s tsunami data, and the results were exciting, said Vasily Titov, the center’s chief scientist in Seattle. “It suggests SWOT data could significantly enhance operational tsunami forecasts — a capability sought since the 2004 Sumatra event.” The tsunami generated by that devastating quake killed thousands of people and caused widespread damage in Indonesia.
More About SWOT
The SWOT satellite was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA JPL, managed for the agency by Caltech in Pasadena, California, leads the U.S. component of the project. For the flight system payload, NASA provided the Ka-band radar interferometer (KaRIn) instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. The Doppler Orbitography and Radioposition Integrated by Satellite system, the dual frequency Poseidon altimeter (developed by Thales Alenia Space), the KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations were provided by CNES. The KaRIn high-power transmitter assembly was provided by CSA.
To learn more about SWOT, visit:
https://swot.jpl.nasa.gov
News Media Contacts
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
ane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
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Last Updated Aug 07, 2025 Related Terms
SWOT (Surface Water and Ocean Topography) Earth Earthquakes Jet Propulsion Laboratory Oceans Tsunamis Explore More
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By NASA
SVEC building locations including parking areas. Where to Park at the Event Center
We have event spaces in multiple buildings. See below for details.
At the main Event Center in building 3, at the front of the building (East side) there is a large lot with standard and accessible spaces. This is the best place to park as it affords the easiest access to the entry doors, which have an ADA accessible ramp. At the rear of the building, there is a secondary large over-flow lot. As this is on the back side of the building, you will need to walk all the way around to enter through the main entrance, or make arrangements to enter through the ADA accessible doors at the rear of the building.
Inside the NASA security fence, at building N232 and the N201 Syverston Auditorium, there is very little parking available and it is first-come first-serve. We highly recommend walking or carpooling to these locations if you are attending an event in either of them
Please keep in mind that if you are driving in, the driver will need a valid, RealID, drivers license. In addition, everyone in the car must have a valid form of ID; Government issued RealID, valid passport, or other form of accepted identification.
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