Members Can Post Anonymously On This Site
NASA’s IXPE Marks Two Years of Groundbreaking X-ray Astronomy
-
Similar Topics
-
By Space Force
The U.S. Space Force honored Ed Mornston, associate deputy chief of Space Operations for Intelligence, for his 50 years of combined military and civilian service.
View the full article
-
By European Space Agency
Estonia marked its 10th anniversary in the European Space Agency alongside the plenary session of the European Interparliamentary Space Conference on 4 September.
View the full article
-
By NASA
Dr. Steven “Steve” Platnick took the NASA agency Deferred Resignation Program (DRP). His last work day was August 8, 2025. Steve spent more than three decades at, or associated with, NASA. While he began his civil servant career at the NASA’s Goddard Space Flight Center (GSFC) in 2002, his Goddard association went back to 1993, first as a contractor and then as one of the earliest employees of the Joint Center for Earth Systems Technology (JCET), a cooperative agreement between the University of Maryland, Baltimore County (UMBC) and GSFC’s Earth Science Division. At JCET Steve helped lead the development of the Atmosphere Physics Track curricula. Previously, he had held an NRC post-doctoral fellow at the NASA’s Ames Research Center. Along with his research work on cloud remote sensing from satellite and airborne sensors, Steve served as the Deputy Director for Atmospheres in GSFC’s Earth Sciences Division from January 2015–July 2024.
Dr. Steve Platnick Image credit: NASA During his time at NASA, Steve played an integral role in the sustainability and advancement of NASA’s Earth Observing System platforms and data. In 2008, he took over as the Earth Observing System (EOS) Senior Project Scientist from Michael King. In this role, he led the EOS Project Science Office, which included support for related EOS facility airborne sensors, ground networks, and calibration labs. The office also supported The Earth Observer newsletter, the NASA Earth Observatory, and other outreach and exhibit activities on behalf of NASA Headquarter’s Earth Science Division and Science Mission Directorate (further details below). From January 2003 – February 2010, Steve served as the Aqua Deputy Project Scientist.
Improving Imager Cloud Algorithms
Steve was actively involved in the Moderate Resolution Imaging Spectroradiometer (MODIS) Science Team serving as the Lead for the MODIS Atmosphere Discipline Team (cloud, aerosol and clear sky products) since 2008 and as the NASA Suomi National Polar-orbiting Partnership (Suomi NPP)/JPSS Atmosphere Discipline Lead/co-Lead from 2012–2020. His research team enhanced, maintained, and evaluated MODIS and Visible Infrared Imaging Radiometer Suite (VIIRS) cloud algorithms that included Level-2 (L2) Cloud Optical/Microphysical Properties components (MOD06 and MYD06 for MODIS on Terra and Aqua, respectively) and the Atmosphere Discipline Team Level-3 (L3) spatial/temporal products (MOD08, MYD08). The L2 cloud algorithms were developed to retrieve thermodynamic phase, optical thickness, effective particle radius, and derived water path for liquid and ice clouds, among other associated datasets. Working closely with longtime University of Wisconsin-Madison colleagues, the team also developed the CLDPROP continuity products designed to bridge the MODIS and VIIRS cloud data records by addressing differences in the spectral coverage between the two sensors; this product is currently in production for VIIRS on Suomi NPP and NOAA-20, as well as MODIS Aqua. The team also ported their CLDPROP code to Geostationary Operational Environmental Satellites (GOES) R-series Advanced Baseline Imager (ABI) and sister sensors as a research demonstration effort.
Steve’s working group participation included the Global Energy and Water Exchanges (GEWEX) Cloud Assessment Working Group (2008–present); the International Cloud Working Group (ICWG), which is part of the Coordination Group for Meteorological Satellites (CGMS), and its original incarnation, the Cloud Retrieval Evaluation Working (CREW) since 2009; and the NASA Observations for Modeling Intercomparison Studies (obs4MIPs) Working Group (2011–2013). Other notable roles included Deputy Chair of the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) Science Definition Team (2011–2012) and membership in the Advanced Composition Explorer (ACE) Science Definition Team (2009–2011), the ABI Cloud Team (2005–2009), and the Climate Absolute Radiance and Refractivity Observatory (CLARREO) Mission Concept Team (2010-2011).
Steve has participated in numerous major airborne field campaigns over his career. His key ER-2 flight scientist and/or science team management roles included the Monterey Area Ship Track experiment (MAST,1994), First (International Satellite Cloud Climatology Project (ISCCP) Regional Experiment – Arctic Cloud Experiment [FIRE-ACE, 1998], Southern Africa Fire-Atmosphere Research Initiative (SAFARI-2000), Cirrus Regional Study of Tropical Anvils and Cirrus Layers – Florida Area Cirrus Experiment (CRYSTAL-FACE, 2002), and Tropical Composition, Cloud and Climate Coupling (TC4, 2007).
Supporting Earth Science Communications
Through his EOS Project Science Office role, Steve has been supportive of the activities of NASA’s Science Support Office (SSO) and personally participated in many NASA Science exhibits at both national and international scientific conferences, including serving as a Hyperwall presenter numerous times.
For The Earth Observer newsletter publication team in particular, Steve replaced Michael King as Acting EOS Senior Project Scientist in June 2008, taking over the authorship of “The Editor’s Corner” beginning with the May–June 2008 issue [Volume 20, Issue 3]. The Acting label was removed beginning with the January–February 2010 issue [Volume 22, Issue 1]. Steve has been a champion of continuing to retain a historical record of NASA science team meetings to maintain a chronology of advances made by different groups within the NASA Earth Science community. He was supportive of the Executive Editor’s efforts to create a series called “Perspectives on EOS,” which ran from 2008–2011 and told the stories of the early years of the EOS Program from the point of view of those who lived them. He also supported the development of articles to commemorate the 25th and 30th anniversary of The Earth Observer. Later, Steve helped guide the transition of the newsletter from a print publication – the November–December 2022 issue was the last printed issue – to fully online by July 2024, a few months after the publication’s 35th anniversary. The Earth Observer team will miss Steve’s keen insight, historical perspective, and encouragement that he has shown through his leadership for the past 85 issues of print and online publications.
A Career Recognized through Awards and Honors
Throughout his career, Steve has amassed numerous honors, including the Goddard William Nordberg Memorial Award for Earth Science in 2023 and the Verner E. Suomi Award from the American Meteorological Society (AMS) in 2016. He was named an AMS Fellow that same year. He received two NASA Agency Honor Awards – the Exceptional Achievement Medal in 2008 and the Exceptional Service Medal in 2015.
Steve received his bachelor’s degree and master’s degree in electrical engineering from Duke University and the University of California, Berkeley, respectively. He earned a Ph.D. in atmospheric sciences from the University of Arizona.
View the full article
-
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
Share
Details
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
6 min read NASA’s Hubble, Chandra Spot Rare Type of Black Hole Eating a Star
NASA’s Hubble Space Telescope and NASA’s Chandra X-ray Observatory have teamed up to identify a…
Article 3 weeks ago 4 min read Stay Cool: NASA Tests Innovative Technique for Super Cold Fuel Storage
Article 4 weeks ago 4 min read NASA’s IXPE Imager Reveals Mysteries of Rare Pulsar
Article 4 weeks ago Keep Exploring Discover Related Topics
Chandra
Space Telescope
IXPE News
Black Holes
Black Holes Black holes are among the most mysterious cosmic objects, much studied but not fully understood. These objects aren’t…
Imaging X-ray Polarimetry Explorer (IXPE)
The Imaging X-ray Polarimetry Explorer (IXPE) is a space observatory built to discover the secrets of some of the most…
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.