Federal Independent Agencies
Here's a look at documents from federal independent agencies
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U.S. Chemical Safety Board Issues Update on Investigation Into Hazardous Nitrogen Oxides Releases at Austin Powder Facilities in Ohio and Tennessee
WASHINGTON, Dec. 18 -- The U.S. Chemical Safety Board issued the following news release on Dec. 17, 2025:
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U.S. Chemical Safety Board Issues Update on Investigation into Hazardous Nitrogen Oxides Releases at Austin Powder Facilities in Ohio and Tennessee
The U.S. Chemical Safety and Hazard Investigation Board (CSB) today released an update on the agency's investigations into incidents involving the release of hazardous nitrogen oxides (NOx) gas at two facilities owned by the Austin Powder company in Ohio and Tennessee. The incidents occurred on November 24, 2024, at the U.S. Nitrogen facility
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WASHINGTON, Dec. 18 -- The U.S. Chemical Safety Board issued the following news release on Dec. 17, 2025:
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U.S. Chemical Safety Board Issues Update on Investigation into Hazardous Nitrogen Oxides Releases at Austin Powder Facilities in Ohio and Tennessee
The U.S. Chemical Safety and Hazard Investigation Board (CSB) today released an update on the agency's investigations into incidents involving the release of hazardous nitrogen oxides (NOx) gas at two facilities owned by the Austin Powder company in Ohio and Tennessee. The incidents occurred on November 24, 2024, at the U.S. Nitrogen facilityin Midway, Tennessee, which Austin Powder owns, and on June 11, 2025, at Austin Powder's Red Diamond explosives manufacturing facility in McArthur, Ohio. Nitrogen oxides are highly hazardous chemicals capable of causing serious respiratory injuries and environmental harm.
Red Diamond Facility -- McArthur, Ohio
On June 11, 2025, over 3,900 pounds of NOx gas was released from the Red Diamond explosives manufacturing facility. The release occurred through an emergency pressure relief valve and a process vent associated with the facility's nitric acid storage and recovery operations. A large, yellow-reddish-brownish-colored plume was seen coming from the facility. The visible emissions led to the evacuation of residents in the nearby town of Zaleski and prompted the Federal Aviation Administration (FAA) to restrict airspace for a 30-mile radius around the facility. The release lasted for over three hours.
CSB Investigators have found that temperatures in a nitric acid storage tank increased dramatically after cooling systems had been shut down for an extended period. During normal operation, the tank's bulk liquid temperature is below 50 degrees Fahrenheit (F). With the chilled water system off, the temperature steadily increased during the week preceding the incident. By the morning of June 10, 2025, approximately 24 hours before the release began, the storage tank temperature had increased to over 80 F, more than 30 F greater than normal. On the morning of the incident, the temperature increased to over 150 F, more than 100 F above normal.
Shortly after 7:54 a.m. on the morning of the incident, maintenance personnel discovered that an emergency pressure relief valve on the tank was repeatedly opening and closing approximately every 30 to 60 seconds, discharging NOx gas. By 8:19 a.m., the excess nitric acid tank's emergency pressure relief valve was open continuously and remained open until approximately 10:19 a.m.
U.S. Nitrogen Facility -- Midway, Tennessee
The U.S. Nitrogen facility in Tennessee produces nitric acid that is used at Austin Powder's Red Diamond explosives manufacturing facility in Ohio, in addition to other substances. On November 24, 2024, two NOx releases occurred during multiple attempts to start up the nitric acid unit at the U.S. Nitrogen facility after the unit had been shut down for several days for maintenance. The releases, which occurred at approximately 6:47 a.m. and 8:42 a.m., resulted in the release of over 900 pounds of NOx gas. The unit was shut down after visible emissions were observed. Like the release in Ohio, a large yellow-reddish-brownish-colored plume of NOx gas was emitted.
The Tennessee Department of Environment and Conservation has issued a Notice of Violation and an order to U.S. Nitrogen, seeking a civil penalty and asserting that the company failed to follow its standard operating procedure for starting up the nitric acid plant.
CSB Chairperson Steve Owens said, "These incidents underscore the serious hazards that can occur with nitric acid processes. We are concerned that hazardous nitrogen oxides gas was released at two Austin Powder facilities in the span of less than seven months."
Ongoing Investigation
The CSB's investigation into the incidents is ongoing. The CSB is reviewing equipment performance, operating procedures, safeguards, alarms, and emergency response actions. Final findings and safety recommendations will be issued in the CSB's final investigation report.
The CSB is an independent, nonregulatory federal agency charged with investigating incidents and hazards that result, or may result, in the catastrophic release of extremely hazardous substances. The agency's core mission activities include conducting incident investigations; formulating preventive or mitigative recommendations based on investigation findings and advocating for their implementation; issuing reports containing the findings, conclusions, and recommendations arising from incident investigations; and conducting studies on chemical hazards.
The agency's board members are appointed by the President subject to Senate confirmation. The Board does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA.
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Original text here: https://www.csb.gov/us-chemical-safety-board-issues-update-on-investigation-into-hazardous-nitrogen-oxides-releases-at-austin-powder-facilities-in-ohio-and-tennessee/
National Science Board: Merit Review for a New Era at NSF
ARLINGTON, Virginia, Dec. 18 (TNSrpt) -- The National Science Board issued the following news on Dec. 17, 2025:
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Merit review for a new era at NSF
Research in service of the American people
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Today, the National Science Board (NSB) released a new report titled Merit Review for a Changing Landscape. The report proposes updates to the U.S. National Science Foundation's Merit Review policy to ensure that NSF-funded research advances national priorities and improves American lives.
"As NSB stated in Vision 2030, we must make sure that everything NSF funds -- from basic research to technology
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ARLINGTON, Virginia, Dec. 18 (TNSrpt) -- The National Science Board issued the following news on Dec. 17, 2025:
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Merit review for a new era at NSF
Research in service of the American people
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Today, the National Science Board (NSB) released a new report titled Merit Review for a Changing Landscape. The report proposes updates to the U.S. National Science Foundation's Merit Review policy to ensure that NSF-funded research advances national priorities and improves American lives.
"As NSB stated in Vision 2030, we must make sure that everything NSF funds -- from basic research to technologytranslation to talent development -- benefits the American people," says NSB Chair Victor McCrary. "We see this report as a key part of how a next generation NSF is relevant in its priorities, operations, and structure for today's science and technology (S&T) challenges while staying firmly grounded in supporting the most meritorious research for tomorrow."
"The agency must also strive for greater accountability of public funds, constructing award portfolios that show American taxpayers what they are getting for their investment," says Wanda Ward, who chaired NSB's Commission on Merit Review.
Over the last three years, NSB investigated how to update NSF's Merit Review to reflect major changes to the S&T landscape over recent decades.
"Our recommendations seek to strengthen NSF's agility and its ability to leverage the perspectives and expertise of people in all sectors, including industry, academia, government and states," says Commission Vice Chair Julia Phillips.
The Board recommends that NSF:
* Boost participation and invite expert reviews from a wider range of industry, research institutions, venture capital, and regions of the country.
* Emphasize that NSF-funded research must deliver societal benefits, including research that advances the nation's economic competitiveness and national security.
* Build NSF's award portfolio at the agency level for greater nimbleness and strategic alignment with national priorities, both current and emerging.
NSF previously announced operational changes to its Merit Review to streamline, clarify, and harmonize agency funding strategies to achieve top scientific and national priorities, similar to those made by the National Institutes of Health. In the coming year, the Board will continue working with NSF leaders to implement NSB recommendations for Merit Review policy changes, such as encouraging verification of previously reported results and pursuing more bold research with high reward potential.
"We can't succeed in a new era with yesterday's playbook," says McCrary. "For our nation to win the race for the future, NSF must develop transformative partnerships with the private sector, states and communities. Together, we can blaze a trail to the next frontiers of science, usher in a Golden Age of American Innovation, and deliver on the promise of science and technology for the benefit of all Americans."
Get more information about the National Science Board (https://www.nsf.gov/nsb).
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REPORT: https://nsf-gov-resources.nsf.gov/files/Merit-Review-Changing-Landscape-2025.pdf
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Original text here: https://www.nsf.gov/nsb/updates/merit-review-new-era-nsf
NSF: Intent to Restructure Critical Weather Science Infrastructure
WASHINGTON, Dec. 18 -- The National Science Foundation issued the following news release on Dec. 17, 2025:
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Intent to restructure critical weather science infrastructure
The U.S. National Science Foundation (NSF) announced today that the agency is reviewing the structure of the research and observational capabilities operated by the NSF National Center for Atmospheric Research (NCAR). NSF remains committed to providing world-class infrastructure for weather modeling, space weather research and forecasting, and other critical functions. To do so, NSF will be engaging with partner agencies,
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WASHINGTON, Dec. 18 -- The National Science Foundation issued the following news release on Dec. 17, 2025:
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Intent to restructure critical weather science infrastructure
The U.S. National Science Foundation (NSF) announced today that the agency is reviewing the structure of the research and observational capabilities operated by the NSF National Center for Atmospheric Research (NCAR). NSF remains committed to providing world-class infrastructure for weather modeling, space weather research and forecasting, and other critical functions. To do so, NSF will be engaging with partner agencies,the research community, and other interested parties to solicit feedback for rescoping the functions of the work currently performed by NCAR.
NSF will publish a Dear Colleague Letter that will inform the agency's follow-on actions. Specifically, NSF will explore options to transfer stewardship of the NCAR-Wyoming Supercomputer to an appropriate operator; divest of or transfer the two NSF aircraft that NCAR manages and operates; and redefine the scope of modeling and forecasting research and operations to concentrate on needs such as seasonal weather prediction, severe storms, and space weather.
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Original text here: https://www.nsf.gov/news/intent-restructure-critical-weather-science-infrastructure
NSF and Partners Invest $9M in AI-Focused Math Education Program
WASHINGTON, Dec. 18 -- The National Science Foundation issued the following news release:
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NSF and partners invest $9M in AI-focused math education program
The U.S. National Science Foundation Directorate for Social, Behavioral, and Economic Sciences (NSF SBE) has launched the Collaboratory to Advance Mathematics Education and Learning (CAMEL), a new $9 million investment aimed at transforming K-12 mathematics learning and education. Supported through an agreement with philanthropic partners, including the Walton Family Foundation, CAMEL advances interdisciplinary collaboration that brings
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WASHINGTON, Dec. 18 -- The National Science Foundation issued the following news release:
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NSF and partners invest $9M in AI-focused math education program
The U.S. National Science Foundation Directorate for Social, Behavioral, and Economic Sciences (NSF SBE) has launched the Collaboratory to Advance Mathematics Education and Learning (CAMEL), a new $9 million investment aimed at transforming K-12 mathematics learning and education. Supported through an agreement with philanthropic partners, including the Walton Family Foundation, CAMEL advances interdisciplinary collaboration that bringstogether artificial intelligence, the science of learning, education practice and data science.
"CAMEL reflects NSF's commitment to advancing the nation's science and technology enterprise by strengthening mathematics education," said Kaye Husbands Fealing, assistant director for NSF SBE. "The knowledge and skills supported through this program are essential for student success and for building a workforce prepared to lead in artificial intelligence, biotechnology, and quantum technologies."
CAMEL uses a two-phase approach to promote both innovation and long-term impact. Phase I supports the creation of new interdisciplinary research networks that generate or enhance high-value AI-ready datasets to advance understanding of K-12 mathematics learning. These networks must include experts in the basic science of learning, education practitioners, and data scientists.
Phase II of CAMEL, open only to Phase I awardees, establishes a national collaboratory, a socio-technical platform designed to build community, strengthen capacity and sustain collaboration beyond individual awards to sustain a united effort to advance math learning and education in K-12. This unique platform will synergize research efforts and resources and stimulate cooperation among individuals and sectors.
CAMEL advances the goals of the administration's executive order on "Advancing Artificial Intelligence Education for American Youth" by strengthening the foundational mathematics skills needed for AI literacy, innovation, and the use of emerging technologies and by creating new AI-ready datasets. By bringing together researchers, classroom practitioners and data scientists, CAMEL supports evidence-based approaches and insights that prepare students and educators to engage with AI-enabled tools and learning environments, while expanding participation in science, technology, engineering and mathematics.
To learn more, please plan to join a webinar on Tuesday, January 6, at 4 p.m. EST. Please register in advance for the webinar (https://nsf.zoomgov.com/webinar/register/WN_54Yk4NhVQUGvCTbPbOvFyw).
Get more information about CAMEL (https://www.nsf.gov/funding/opportunities/collaboratory-advance-mathematics-education-learning-k-12).
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Original text here: https://www.nsf.gov/news/nsf-partners-invest-9m-ai-focused-math-education-program
NASA's Perseverance Mars Rover Ready to Roll for Miles in Years Ahead
PASADENA, California, Dec. 18 (TNSres) -- NASA Jet Propulsion Laboratory issued the following news:
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NASA's Perseverance Mars Rover Ready to Roll for Miles in Years Ahead
The rover has been acing a long-term series of durability tests, making the most of its enhanced navigation capabilities, and ferreting out new findings about Mars' geologic past.
After nearly five years on Mars, NASA's Perseverance rover has traveled almost 25 miles (40 kilometers), and the mission team has been busy testing the rover's durability and gathering new science findings on the way to a new region nicknamed
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PASADENA, California, Dec. 18 (TNSres) -- NASA Jet Propulsion Laboratory issued the following news:
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NASA's Perseverance Mars Rover Ready to Roll for Miles in Years Ahead
The rover has been acing a long-term series of durability tests, making the most of its enhanced navigation capabilities, and ferreting out new findings about Mars' geologic past.
After nearly five years on Mars, NASA's Perseverance rover has traveled almost 25 miles (40 kilometers), and the mission team has been busy testing the rover's durability and gathering new science findings on the way to a new region nicknamed"Lac de Charmes," where it will be searching for rocks to sample in the coming year.
Like its predecessor Curiosity, which has been exploring a different region of Mars since 2012, Perseverance was made for the long haul. NASA's Jet Propulsion Laboratory in Southern California, which built Perseverance and leads the mission, has continued testing the rover's parts here on Earth to make sure the six-wheeled scientist will be strong for years to come. This past summer, JPL certified that the rotary actuators that turn the rover's wheels can perform optimally for at least another 37 miles (60 kilometers); comparable brake testing is underway as well.
Over the past two years, engineers have extensively evaluated nearly all the vehicle's subsystems in this way, concluding that they can operate until at least 2031.
"These tests show the rover is in excellent shape," said Perseverance's deputy project manager, Steve Lee of JPL, who presented the results on Wednesday at the American Geophysical Union's annual meeting, the largest gathering of planetary scientists in the United States. "All the systems are fully capable of supporting a very long-term mission to extensively explore this fascinating region of Mars."
Perseverance has been driving through Mars' Jezero Crater, the site of an ancient lake and river system, where it has been collecting scientifically compelling rock core samples. In fact, in September, the team announced that a sample from a rock nicknamed "Cheyava Falls" contains a potential fingerprint of past microbial life.
More efficient roving
In addition to a hefty suite of six science instruments, Perseverance packs more autonomous capabilities than past rovers. A paper (https://ieeexplore.ieee.org/document/11265757) published recently in IEEE Transactions on Field Robotics highlights an autonomous planning tool called Enhanced Autonomous Navigation, or ENav. The software looks up to 50 feet (15 meters) ahead for potential hazards, then chooses a path without obstacles and tells Perseverance's wheels how to steer there.
Engineers at JPL meticulously plan each day of the rover's activities on Mars. But once the rover starts driving, it's on its own and sometimes has to react to unexpected obstacles in the terrain. Past rovers could do this to some degree, but not if these obstacles were clustered near each other. They also couldn't react as far in advance, resulting in the vehicles driving slower while approaching sand pits, rocks, and ledges. In contrast, ENav's algorithm evaluates each rover wheel independently against the elevation of terrain, trade-offs between different routes, and "keep-in" or "keep-out" areas marked by human operators for the path ahead.
"More than 90% of Perseverance's journey has relied on autonomous driving, making it possible to quickly collect a diverse range of samples," said JPL autonomy researcher Hiro Ono, a paper lead author. "As humans go to the Moon and even Mars in the future, long-range autonomous driving will become more critical to exploring these worlds."
New science
A paper (https://www.science.org/doi/10.1126/science.adu8264) published Wednesday in Science details what Perseverance discovered in the "Margin Unit," a geologic area at the margin, or inner edge, of Jezero Crater. The rover collected three samples from that region. Scientists think these samples may be particularly useful for showing how ancient rocks from Mars' deep interior interacted with water and the atmosphere, helping create conditions supportive for life.
From September 2023 to November 2024, Perseverance ascended 1,312 feet (400 meters) of the Margin Unit, studying rocks along the way -- especially those containing the mineral olivine. Scientists use minerals as timekeepers because crystals within them can record details about the precise moment and conditions in which they formed.
Jezero Crater and the surrounding area holds large reserves of olivine, which forms at high temperatures, typically deep within a planet, and offers a snapshot of what was going on in the planet's interior. Scientists think the Margin Unit's olivine was made in an intrusion, a process where magma pushes into underground layers and cools into igneous rock. In this case, erosion later exposed that rock to the surface, where it could interact with water from the crater's ancient lake and carbon dioxide, which was abundant in the planet's early atmosphere.
Those interactions form new minerals called carbonates, which can preserve signs of past life, along with clues as to how Mars' atmosphere changed over time.
"This combination of olivine and carbonate was a major factor in the choice to land at Jezero Crater," said the new paper's lead author, Perseverance science team member Ken Williford of Blue Marble Space Institute of Science in Seattle. "These minerals are powerful recorders of planetary evolution and the potential for life."
Together, the olivine and carbonates record the interplay between rock, water, and atmosphere inside the crater, including how each changed over time. The Margin Unit's olivine appeared to have been altered by water at the base of the unit, where it would have been submerged. But the higher Perseverance went, the more the olivine bore textures associated with magma chambers, like crystallization, and fewer signs of water alteration.
As Perseverance leaves the Margin Unit behind for Lac de Charmes, the team will have the chance to collect new olivine-rich samples and compare the differences between the two areas.
More about Perseverance
Managed for NASA by Caltech, NASA's Jet Propulsion Laboratory in Southern California built and manages operations of the Perseverance rover on behalf of the agency's Science Mission Directorate as part of NASA's Mars Exploration Program portfolio.
To learn more about Perseverance, visit:
https://science.nasa.gov/mission/mars-2020-perseverance
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Original text here: https://www.jpl.nasa.gov/news/nasas-perseverance-mars-rover-ready-to-roll-for-miles-in-years-ahead/
NASA Study Suggests Saturn's Moon Titan May Not Have Global Ocean
PASADENA, California, Dec. 18 (TNSres) -- NASA Jet Propulsion Laboratory issued the following news:
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NASA Study Suggests Saturn's Moon Titan May Not Have Global Ocean
Reanalysis of data from NASA's Cassini mission has revealed Saturn's moon may instead have layers of slush with isolated pockets of liquid water.
A key discovery from NASA's Cassini mission in 2008 was that Saturn's largest moon Titan may have a vast water ocean below its hydrocarbon-rich surface. But reanalysis of mission data suggests a more complicated picture: Titan's interior is more likely composed of ice, with layers
... Show Full Article
PASADENA, California, Dec. 18 (TNSres) -- NASA Jet Propulsion Laboratory issued the following news:
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NASA Study Suggests Saturn's Moon Titan May Not Have Global Ocean
Reanalysis of data from NASA's Cassini mission has revealed Saturn's moon may instead have layers of slush with isolated pockets of liquid water.
A key discovery from NASA's Cassini mission in 2008 was that Saturn's largest moon Titan may have a vast water ocean below its hydrocarbon-rich surface. But reanalysis of mission data suggests a more complicated picture: Titan's interior is more likely composed of ice, with layersof slush and small pockets of warm water that form near its rocky core.
Led by researchers at NASA's Jet Propulsion Laboratory in Southern California and published (https://www.nature.com/articles/s41586-025-09818-x) in the journal Nature on Wednesday, the new study could have implications for scientists' understanding of Titan and other icy moons throughout our solar system.
"This research underscores the power of archival planetary science data. It is important to remember that the data these amazing spacecraft collect lives on so discoveries can be made years, or even decades, later as analysis techniques get more sophisticated," said Julie Castillo-Rogez, senior research scientist at JPL and a coauthor of the study. "It's the gift that keeps giving."
To remotely probe planets, moons, and asteroids, scientists study the radio frequency communications traveling back and forth between spacecraft and NASA's Deep Space Network. It's a multilayered process. Because a moon's body may not have a uniform distribution of mass, its gravity field will change as a spacecraft flies through it, causing the spacecraft to speed up or slow down slightly. In turn, these variations in speed alter the frequency of the radio waves going to and from the spacecraft -- an effect known as Doppler shift. Analyzing the Doppler shift can lend insight into a moon's gravity field and its shape, which can change over time as it orbits within its parent planet's gravitational pull.
This shape shifting is called tidal flexing. In Titan's case, Saturn's immense gravitational field squeezes the moon when Titan is closer to the planet during its slightly elliptical orbit, and it stretches the moon when it is farthest. Such flexing creates energy that is lost, or dissipated, in the form of internal heating.
When mission scientists analyzed radio-frequency data gathered during the now-retired Cassini mission's 10 close approaches of Titan, they found the moon to be flexing so much that they concluded it must have a liquid interior, since a solid interior would have flexed far less. (Think of a balloon filled with water versus a billiard ball.)
New technique
The new research highlights another possible explanation for this malleability: an interior composed of layers featuring a mix of ice and water that allows the moon to flex. In this scenario, there would be a lag of several hours between Saturn's tidal pull and when the moon shows signs of flexing -- much slower than if the interior were fully liquid. A slushy interior would also exhibit a stronger energy dissipation signature in the moon's gravity field than a liquid one, because these slush layers would generate friction and produce heat when the ice crystals rub against one another. But there was nothing apparent in the data to suggest this was happening.
So the study authors, led by JPL postdoctoral researcher Flavio Petricca, looked more closely at the Doppler data to see why. By applying a novel processing technique, they reduced the noise in the data. What emerged was a signature that revealed strong energy loss deep inside Titan. The researchers interpreted this signature to be coming from layers of slush, overlaid by a thick shell of solid ice.
Based on this new model of Titan's interior, the researchers suggest that the only liquid would be in the form of pockets of meltwater. Heated by dissipating tidal energy, the water pockets slowly travel toward the frozen layers of ice at the surface. As they rise, they have the potential to create unique environments enriched by organic molecules being supplied from below and from material delivered via meteorite impacts on the surface.
"Nobody was expecting very strong energy dissipation inside Titan. But by reducing the noise in the Doppler data, we could see these smaller wiggles emerge. That was the smoking gun that indicates Titan's interior is different from what was inferred from previous analyses," said Petricca. "The low viscosity of the slush still allows the moon to bulge and compress in response to Saturn's tides, and to remove the heat that would otherwise melt the ice and form an ocean."
Potential for life
"While Titan may not possess a global ocean, that doesn't preclude its potential for harboring basic life forms, assuming life could form on Titan. In fact, I think it makes Titan more interesting," Petricca added. "Our analysis shows there should be pockets of liquid water, possibly as warm as 20 degrees Celsius (68 degrees Fahrenheit), cycling nutrients from the moon's rocky core through slushy layers of high-pressure ice to a solid icy shell at the surface."
More definitive information could come from NASA's next mission to Saturn. Launching no earlier than 2028, the agency's Dragonfly mission to the hazy moon could provide the ground truth. The first-of-its-kind rotorcraft will explore Titan's surface to investigate the moon's habitability. Carrying a seismometer, the mission may provide key measurements to probe Titan's interior, depending on what seismic events occur while it is on the surface.
More about Cassini
The Cassini-Huygens mission was a cooperative project of NASA, ESA (European Space Agency), and the Italian Space Agency. A division of Caltech in Pasadena, JPL managed the mission for NASA's Space Mission Directorate in Washington and designed, developed, and assembled the Cassini orbiter.
To learn more about NASA's Cassini mission, visit:
https://science.nasa.gov/mission/cassini/
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Original text here: https://www.jpl.nasa.gov/news/nasa-study-suggests-saturns-moon-titan-may-not-have-global-ocean/
Harvard-Smithsonian Center for Astrophysics: X-Ray Space Telescope Gives Sharpest-Ever Glimpse at Growth of a Rapidly-Spinning Black Hole
CAMBRIDGE, Massachusetts, Dec. 18 (TNSjou) -- The Harvard-Smithsonian Center for Astrophysics issued the following news release:
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X-ray Space Telescope Gives Sharpest-Ever Glimpse at Growth of a Rapidly-Spinning Black Hole
The first results on the iconic active galactic nucleus MCG-6-30-15 captured with the XRISM mission show the most precise signatures yet of its supermassive black hole's extreme gravity and the outflows that shape its galaxy.
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Astronomers have obtained the sharpest-ever X-ray spectrum of an iconic active galaxy, providing the most accurate, precise view ever obtained
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CAMBRIDGE, Massachusetts, Dec. 18 (TNSjou) -- The Harvard-Smithsonian Center for Astrophysics issued the following news release:
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X-ray Space Telescope Gives Sharpest-Ever Glimpse at Growth of a Rapidly-Spinning Black Hole
The first results on the iconic active galactic nucleus MCG-6-30-15 captured with the XRISM mission show the most precise signatures yet of its supermassive black hole's extreme gravity and the outflows that shape its galaxy.
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Astronomers have obtained the sharpest-ever X-ray spectrum of an iconic active galaxy, providing the most accurate, precise view ever obtainedof the extreme relativistic effects imprinted onto the spacetime around a supermassive black hole.
Using a powerful trio of telescopes headlined by the Japan Aerospace Exploration Agency (JAXA)/NASA XRISM mission, the research team, led by high-energy astrophysicist Laura Brenneman of the Center for Astrophysics | Harvard & Smithsonian, isolated the broad iron emission line and associated "reflection" that signify a rapidly-spinning black hole.
Previous X-ray spectral observations have lacked the resolution to separate the various emission and absorption features in this energy range, but XRISM's unmatched spectral resolution allows scientists to examine the black hole's immediate environment with unprecedented accuracy, the authors explained.
"Astrophysical black holes have only two properties: mass and spin," Brenneman said. "We can estimate their masses by several different means, but measuring their spins is much harder and requires collecting data from gas that is orbiting the black hole immediately outside the event horizon. For supermassive black holes in active galactic nuclei, this is best accomplished by obtaining X-ray spectra with high signal-to-noise and spectral resolution."
Astronomers have long suspected that a large fraction of the X-ray signals from the galaxy known as MCG-6-30-15 come from matter very close to the galaxy's central supermassive black hole, which is estimated to be about 2 million times the mass of our Sun.
But in regions this close to a supermassive black hole's event horizon, gravity stretches and warps light in line with Einstein's theories of relativity, explains Brenneman, making it hard to separate these light signals.
Combining results from XRISM's newly commissioned, ultra-high-resolution "Resolve" X-ray instrument with the broadband power of the European Space Agency's XMM-Newton and NASA's NuSTAR produced data that allowed the scientists to separate the spectrum of matter near the event horizon from emission and absorption lines originating in more distant gas.
The study confirms a distinctive, warped iron emission line in the X-ray spectrum, which is evidence of material orbiting at extreme speeds near the event horizon of the black hole rather than being created by outflowing winds along the line of sight to the galaxy. The fast-moving inner disk produces about 50 times as much X-ray reflection as the gas clouds further away, the study suggests.
A companion publication led by Dan Wilkins of Ohio State University, recently submitted to The Astrophysical Journal, builds on this research by analyzing the spectra at different times throughout the observation. The results confirm and refine the measurement of the rapid black hole spin and provide new insight into the properties of the corona, the highly-energized region just outside the black hole that is producing most of the X-ray emission we observe. The exact nature of the corona remains one of the most intriguing mysteries in astrophysics.
Brenneman said that astronomers will now be able to use XRISM to check the accuracy of previous black hole spin measurements made with lower-resolution X-ray spectra.
"We want to go back and look at all of the sources for which we have lower-resolution spectra and observe them with XRISM, and say, 'Okay, now that we're confident we can separate out the narrow and the broad features, how accurate were our previous spin measurements?'" she explained.
The data have also revealed at least five different "zones" of a wind being driven outward as a byproduct of accretion onto the black hole, said Brenneman.
"Understanding these winds in addition to the black hole's spin is important because they can tell us how galaxies grow and evolve, either primarily by collecting gas or by mergers with other galaxies and black holes," said Brenneman. "So measuring these two quantities accurately gives us a holistic view of the symbiotic relationship between supermassive black holes and their host galaxies."
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Resource
Brenneman, L. W. et al, "A Sharper View of the X-ray Spectrum of MCG--6-30-15 with XRISM, XMM-Newton and NuSTAR," Astrophysical Journal, 2025 Dec 17, doi: https://doi.org/10.3847/1538-4357/ae1225
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About the Center for Astrophysics | Harvard & Smithsonian
The Center for Astrophysics | Harvard & Smithsonian is a collaboration between Harvard and the Smithsonian designed to ask--and ultimately answer--humanity's greatest unresolved questions about the nature of the universe. The Center for Astrophysics is headquartered in Cambridge, MA, with research facilities across the U.S. and around the world.
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Original text here: https://www.cfa.harvard.edu/news/new-x-ray-space-telescope-gives-sharpest-ever-glimpse-growth-rapidly-spinning-black-hole
