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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The blazar BL Lacertae, a supermassive black hole surrounded by a bright disk and jets oriented toward Earth, provided scientists with a unique opportunity to answer a longstanding question: How are X-rays generated in extreme environments like this?
NASA’s IXPE (Imaging X-ray Polarimetry Explorer) collaborated with radio and optical telescopes to find answers. The results (preprint available here), to be published in the journal Astrophysical Journal Letters, show that interactions between fast-moving electrons and particles of light, called photons, must lead to this X-ray emission.
This artist’s concept depicts the central region of the blazar BL Lacertae, a supermassive black hole surrounded by a bright disk and a jet oriented toward Earth. The galaxy’s central black hole is surrounded by swirls of orange in various shades representing the accretion disk of material falling toward the black hole. While black holes are known for pulling in material, this accretion process can result in the ejection of jets of electrons at nearly the speed of light. The jet of matter is represented by the cone of light that starts at the center of the black hole and widens out as it reaches the bottom of the image. It is streaked with lines of white, pink and purple which represent helix-shaped magnetic fields. We can observe these jets in many wavelengths of light including radio, optical, and X-ray. NASA’s Imaging X-ray Polarimetry Explorer (IXPE) recently collaborated with radio and optical telescopes to observe this jet and determine how the X-rays are generated in these types of celestial environments.NASA/Pablo Garcia Scientists had two competing possible explanations for the X-rays, one involving protons and one involving electrons. Each of these mechanisms would have a different signature in the polarization of X-ray light. Polarization is a property of light that describes the average direction of the electromagnetic waves that make up light.
If the X-rays in a black hole’s jets are highly polarized, that would mean that the X-rays are produced by protons gyrating in the magnetic field of the jet or protons interacting with jet’s photons. If the X-rays have a lower polarization degree, it would suggest that electron-photons interactions lead to X-ray production.
IXPE, which launched Dec. 9, 2021, is the only satellite flying today that can make such a polarization measurement.
“This was one of the biggest mysteries about supermassive black hole jets” said Iván Agudo, lead author of the study and astronomer at the Instituto de Astrofísica de Andalucía – CSIC in Spain. “And IXPE, with the help of a number of supporting ground-based telescopes, finally provided us with the tools to solve it.”
Astronomers found that electrons must be the culprits through a process called Compton Scattering. Compton scattering (or the Compton effect) happens when a photon loses or gains energy after interacting with a charged particle, usually an electron. Within jets from supermassive black holes, electrons move near the speed of light. IXPE helped scientists learn that, in the case of a blazar jet, the electrons have enough energy to scatter photons of infrared light up to X-ray wavelengths.
BL Lacertae (BL Lac for short) is one of the first blazars ever discovered, originally thought to be a variable star in the Lacerta constellation. IXPE observed BL Lac at the end of November 2023 for seven days along with several ground-based telescopes measuring optical and radio polarization at the same time. While IXPE observed BL Lac in the past, this observation was special. Coincidentally, during the X-ray polarization observations, the optical polarization of BL Lac reached a high number: 47.5%.
“This was not only the most polarized BL Lac has been in the past 30 years, this is the most polarized any blazar has ever been observed!” said Ioannis Liodakis, one of the primary authors of the study and astrophysicist at the Institute of Astrophysics – FORTH in Greece.
IXPE found the X-rays were far less polarized than the optical light. The team was not able to measure a strong polarization signal and determined that the X-rays cannot be more polarized than 7.6%. This proved that electrons interacting with photons, via the Compton effect, must explain the X-rays.
The fact that optical polarization was so much higher than in the X-rays can only be explained by Compton scattering.
Steven Ehlert
Project Scientist for IXPE at Marshall Space Flight Center
“The fact that optical polarization was so much higher than in the X-rays can only be explained by Compton scattering”, said Steven Ehlert, project scientist for IXPE and astronomer at the Marshall Space Flight Center.
“IXPE has managed to solve another black hole mystery” said Enrico Costa, astrophysicist in Rome at the Istituto di Astrofísica e Planetologia Spaziali of the Istituto Nazionale di Astrofísica. Costa is one of the scientists who conceived this experiment and proposed it to NASA 10 years ago, under the leadership of Martin Weisskopf, IXPE’s first principal investigator. “IXPE’s polarized X-ray vision has solved several long lasting mysteries, and this is one of the most important. In some other cases, IXPE results have challenged consolidated opinions and opened new enigmas, but this is how science works and, for sure, IXPE is doing very good science.”
What’s next for the blazar research?
“One thing we’ll want to do is try to find as many of these as possible,” Ehlert said. “Blazars change quite a bit with time and are full of surprises.”
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
Elizabeth Landau
NASA Headquarters
elizabeth.r.landau@nasa.gov
202-358-0845
Lane Figueroa
Marshall Space Flight Center, Huntsville, Ala.
lane.e.figueroa@nasa.gov
256.544.0034
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Last Updated May 06, 2025 EditorBeth RidgewayContactElizabeth R. Landauelizabeth.r.landau@nasa.govLocationMarshall Space Flight Center Related Terms
Marshall Space Flight Center IXPE (Imaging X-ray Polarimetry Explorer) Marshall Astrophysics Explore More
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Black Holes
Black Holes Black holes are among the most mysterious cosmic objects, much studied but not fully understood. These objects aren’t…
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By NASA
The Goddard OCKO has a large collection of case studies covering a wide range of missions and technical topics, including launch decision making, project management, procurement, instrument development, risk management, systems engineering and more. These case studies can be used to facilitate learning of critical knowledge and lessons that enable mission success.
Click Here to Access the Case Studies (Internal NASA Only).
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By USH
Several days ago, a massive blackout swept across large parts of Spain, Portugal, and parts of southern France. Millions were left without power as the interconnected European energy grid experienced a rare and abrupt failure. While authorities quickly pointed to a "rare atmospheric phenomenon" as the cause, not everyone is convinced.
Here are some explanations of authorities as well as controversial theories:
According to REN, Portugal’s national electricity grid operator, the blackout was triggered by a fault originating in Spain’s power infrastructure. The disruption, they claim, was linked to "induced atmospheric variation", a term referring to extreme temperature differences that led to anomalous oscillations in high-voltage transmission lines. These oscillations reportedly caused synchronization failures between regional grid systems, ultimately sparking a chain reaction of failures across the European network.
What makes the situation even more intriguing is that just days before the blackout, Spain hit a historic energy milestone. On April 16, for the first time, the country’s electricity demand was met entirely by renewable energy sources - solar, wind, and hydro, during a weekday. It raises questions whether the outage was caused by a technical failure of this new renewable energy system.
While this achievement is noteworthy, it also exposes the fragility of a grid increasingly reliant on variable energy sources, especially solar, which can fluctuate dramatically with weather and atmospheric conditions.
Despite official explanations, some experts and observers remain skeptical. There were no solar flares or geomagnetic storms in the days leading up to the blackout, and solar activity had been relatively calm. Critics argue that while atmospheric disturbances may have played a role, they are not sufficient to explain such a widespread, synchronized failure.
Despite the fact that the blackout this time was probably not caused by solar flares or geomagnetic storms it has been proven that Earth’s magnetic shield is rapidly weakening, leaving us increasingly vulnerable to powerful solar storms. The magnetic north pole is accelerating toward Siberia, and the South Atlantic Anomaly continues to expand, ominous signs that a looming plasma event could bring consequences far beyond just technological disruption.
This has led to speculation that the blackout could have been intentional, possibly even a test run for handling future crises or threats to infrastructure.
Among the more controversial theories is the suggestion that this event might have involved the use of a graphite bomb, a non-lethal weapon designed to disable power grids. These devices disperse ultra-fine carbon filaments into high-voltage power lines, causing short circuits by creating conductive paths between lines. Such an attack would appear as a grid malfunction but could be devastating in scale.
Another controversial theory is that the outage has been caused by weather manipulation systems such as HAARP or the Ice Cube Neutrino observatory, constructed at the Amundsen–Scott South Pole Station in Antarctica.
Could this have been a covert drill or a demonstration of vulnerability? Some point to global forums, such as the World Government Summit, where figures like Klaus Schwab have warned about Black Swan: An unpredictable event that is beyond what is normally expected of a situation and has potentially severe consequences.
Whether the blackout was triggered by a rare natural event, a technical failure, or something more deliberate, it seems only a matter of time before we face a true Black Swan event. View the full article
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
One of several NASA distributed sensing ground nodes is set up in the foreground while an experimental air taxi aircraft owned by Joby Aviation sits in the background near NASA’s Armstrong Flight Research Center in Edwards, California, on March 12, 2025. NASA is collecting information during this study to help advance future air taxi flights, especially those occurring in cities, to track aircraft moving through traffic corridors and around landing zones.NASA/Genaro Vavuris NASA engineers began using a network of ground sensors in March to collect data from an experimental air taxi to evaluate how to safely integrate such vehicles into airspace above cities – in all kinds of weather.
Researchers will use the campaign to help improve tools to assist with collision avoidance and landing operations and ensure safe and efficient air taxi operations in various weather conditions.
For years, NASA has looked at how wind shaped by terrain, including buildings in urban areas, can affect new types of aircraft. The latest test, which is gathering data from a Joby Aviation demonstrator aircraft, looks at another kind of wind – that which is generated by the aircraft themselves.
Joby flew its air taxi demonstrator over NASA’s ground sensor array near the agency’s Armstrong Flight Research Center in Edwards, California producing air flow data. The Joby aircraft has six rotors that allow for vertical takeoffs and landings, and tilt to provide lift in flight. Researchers focused on the air pushed by the propellers, which rolls into turbulent, circular patterns of wind.
NASA aeronautical meteorologist Luke Bard adjusts one of several wind lidar (light detection and ranging) sensors near NASA’s Armstrong Flight Research Center in Edwards, California, on March 12, 2025, in preparation to collect data from Joby Aviation’s experimental air taxi aircraft. NASA is collecting information during this study to help advance weather-tolerant air taxi operations for the entire industryNASA/Genaro Vavuris This rolling wind can affect the aircraft’s performance, especially when it’s close to the ground, as well as others flying in the vicinity and people on the ground. Such wind turbulence is difficult to measure, so NASA enhanced its sensors with a new type of lidar – a system that uses lasers to measure precise distances – and that can map out the shapes of wind features.
“The design of this new type of aircraft, paired with the NASA lidar technology during this study, warrants a better understanding of possible wind and turbulence effects that can influence safe and efficient flights,” said Grady Koch, lead for this research effort, from NASA’s Langley Research Center in Hampton, Virginia.
Data to Improve Aircraft Tracking
NASA also set up a second array of ground nodes including radar, cameras, and microphones in the same location as the sensors to provide additional data on the aircraft. These nodes will collect tracking data during routine flights for several months.
The agency will use the data gathered from these ground nodes to demonstrate the tracking capabilities and functions of its “distributed sensing” technology, which involves embedding multiple sensors in an area where aircraft are operating.
One of multiple NASA distributed sensing ground nodes is set up in the foreground while an experimental air taxi aircraft owned by Joby Aviation hovers in the background near NASA’s Armstrong Flight Research Center in Edwards, California, on March 12, 2025. NASA is collecting information during this study to help advance future air taxi flights, especially those occurring in cities, to track aircraft moving through traffic corridors and around landing zones.NASA/Genaro Vavuris This technology will be important for future air taxi flights, especially those occurring in cities by tracking aircraft moving through traffic corridors and around landing zones. Distributed sensing has the potential to enhance collision avoidance systems, air traffic management, ground-based landing sensors, and more.
“Our early work on a distributed network of sensors, and through this study, gives us the opportunity to test new technologies that can someday assist in airspace monitoring and collision avoidance above cities,” said George Gorospe, lead for this effort from NASA’s Ames Research Center in California’s Silicon Valley.
Using this data from an experimental air taxi aircraft, NASA will further develop the technology needed to help create safer air taxi flights in high-traffic areas. Both of these efforts will benefit the companies working to bring air taxis and drones safely into the airspace.
The work is led by NASA’s Transformational Tools and Technologies and Convergent Aeronautics Solutions projects under the Transformative Aeronautics Concepts program in support of NASA’s Advanced Air Mobility mission. NASA’s Advanced Air Mobility mission seeks to deliver data to guide the industry’s development of electric air taxis and drones.
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Last Updated Apr 17, 2025 EditorDede DiniusContactTeresa Whitingteresa.whiting@nasa.govLocationArmstrong Flight Research Center Related Terms
Armstrong Flight Research Center Advanced Air Mobility Ames Research Center Convergent Aeronautics Solutions Drones & You Flight Innovation Glenn Research Center Langley Research Center Transformational Tools Technologies Transformative Aeronautics Concepts Program Explore More
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By European Space Agency
The European Space Agency's XMM-Newton is playing a crucial role in investigating the longest and most energetic bursts of X-rays seen from a newly awakened black hole. Watching this strange behaviour unfold in real time offers a unique opportunity to learn more about these powerful events and the mysterious behaviour of massive black holes.
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