SPACE/COSMOS
Simplifying black hole mergers — the universe’s most violent phenomena
The size of a black hole that results from the merger of two orbiting black holes predicted using simple thermodynamics
Penn State
image:
Artist's impression of orbiting black holes about to merge. New research, led by Penn State physicists, shows that the size of the resulting merged black hole can be predicted using simple thermodynamics.
view moreCredit: LIGO/Caltech/MIT/R. Hurt (IPAC)
UNIVERSITY PARK, Pa. — When two black holes orbit each other, they will eventually spiral inward and collide in one of the most violent phenomena in the universe. The event is so energetic that it significantly distorts the universe around it. It emits gravitational waves — ripples in the fabric of spacetime — that are strong enough to be detected with precision instruments on Earth even when they originate billions of light-years away. These gravitational waves carry information about the event that physicists use to predict the size of the merger’s resulting new larger black hole — referred to as a remnant. But accurate predictions involve complex equations originally developed by Einstein as part of his theory of general relativity that require supercomputers to solve. Now, a team of researchers, led by physicists at Penn State, have shown that there may be simpler way, which also points towards obtaining a deeper understanding of the physics contained in those complex equations.
A paper describing the research published today (July 2) in the journal Physical Review Letters where it is being highlighted as an “editor’s suggestion.”
“The final black hole after a merger is ringing like a struck bell, and it radiates away more gravitational waves until it settles into a calm, stable state described by just two numbers — its final mass and spin,” said Monica Rincon-Ramirez, a postdoctoral scholar in physics in the Penn State Eberly College of Science and the first author of the paper. “The question we asked is: Can we predict what that final state looks like using arguments from thermodynamics?"
Thermodynamics is the branch of physics that studies how quantities such as energy, heat and entropy determine the macroscopic behavior of systems containing many interacting particles — from gases in engines and the atmosphere to everyday activities such as cooking. General relativity, on the other hand, describes gravity through the geometry of spacetime, and is thus primarily needed to describe astronomical observations. Before Stephen Hawking showed that black holes could radiate energy, they were generally believed to fall outside the realm of thermodynamics.
Another recent study from Penn State overcomes a limitation of Hawking’s formulation of black hole mechanics, making them applicable to dynamic black holes that form, merge, and evaporate.
“The concepts and laws of thermodynamics apply to systems with many particles, like gases,” said Nathan K. Johnson-McDaniel, a postdoctoral researcher at the University of Mississippi who earned a doctorate in physics at Penn State in 2011 and an author of the paper. “Usually, we are interested in predicting the coarse-grained properties of these gases and not what every molecule is doing. Black holes, on the other hand, are described by the deterministic equations of general relativity and seemingly have no relationship with the gases. But starting in the 1970s, leading physicists found an interesting parallel between the properties of black holes and those of gases. We wanted to extend this analogy to binary black hole systems.”
The new work suggests that once the energy and angular momentum — a measure of the system’s rotational motion — carried away by gravitational waves are properly accounted for, the final black hole appears to be the state that maximizes entropy, the measure of randomness in a system, tracking the natural tendency of the universe to go from a state of order to a state of chaos.
"Entropy is essentially a measure of disorder, or more precisely, of how many ways something can be arranged,” said Vaishak Prasad, a postdoctoral researcher in astronomy and astrophysics at Penn State and an author of the paper. “A messy room has high entropy — there are countless ways things can be strewn about. A perfectly tidy room has low entropy — there are only a few arrangements that count as 'tidy.' Nature tends to drift toward high entropy states simply because there are more of them. Our results suggest that black hole mergers do something similar."
The team developed what they call the “maximum entropy conjecture for black hole mergers,” which is strikingly similar to ordinary thermodynamics.
“When two hot gases are brought into contact, one does not need to track every microscopic interaction of the molecules in the gases to determine the final state of the combined gas,” said Eugenio Bianchi, professor of physics at Penn State and an author of the paper. “Maximizing entropy, while accounting for other physical laws, predicts the outcome.”
The team’s new conjecture suggests that a related principle may govern black hole mergers.
“The central finding emerged from studying how the merging black holes’ evolving mass and angular momentum map onto those of a sequence of hypothetical rotating black hole remnants,” Rincon-Ramirez said. “Remarkably, we observe that the entropy of this sequence reaches a maximum at values strikingly close to the mass and angular momentum of the actual final remnant predicted independently by numerical relativity simulations. The agreement is within a few percent.”
When two black holes collide and merge to form a single black hole, the remnant black hole left behind seems to “forget” almost everything about the collision, except its mass and spin, the researchers explained.
“We found that the most natural way to describe what it does remember can be explained using thermodynamic concepts,” said B.S. Sathyaprakash, Elsbach Professor of Physics and professor of astronomy and astrophysics in the Penn State Eberly College of Science, the leader of the research team. “This work explores a surprising possibility at the intersection of gravity, black hole physics and thermodynamics that goes beyond the established laws of black hole mechanics and thermodynamics and raises a potentially transformative question: Could entropy maximization be a fundamental organizing principle governing black hole interactions more generally?”
In addition to Rincon-Ramirez, Johnson-McDaniel, Prasad, Bianchi and Sathyaprakash, the research team included Ish Gupta, a postdoctoral researcher at the University of California, Berkeley, who earned a doctorate in physics at Penn State in 2025. The U.S. National Science Foundation funded the research.
Journal
Physical Review Letters
Article Title
Maximum Entropy Conjecture for Black Hole Mergers
Satellites are transforming biodiversity monitoring for global nature targets, but major gaps remain
University of Oxford
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Trinity F90+ drone landing in Ghana moist tropical forests and piloted by Jesús Aguirre Gutiérrez.
view moreCredit: @Jesús Aguirre Gutiérrez
• New review highlights how remote sensing could help countries monitor progress under the Global Biodiversity Framework (GBF)
• Tropical forests are a key focus, with satellites now capturing important aspects of ecosystem structure and function
• Major gaps remain in observing species-level, evolutionary and genetic dimensions of biodiversity from space
• The authors emphasise that field data remain essential, alongside rapidly advancing satellite technologies
A new scientific review outlines how satellites and other remote sensing technologies are increasingly shaping how biodiversity and ecosystem health can be monitored at scale — offering new opportunities for countries reporting under international nature targets, while also underscoring important limitations.
Published in Nature Reviews Biodiversity, the study synthesises current knowledge on the use of satellite-based Earth observation, LiDAR, radar and airborne sensing to track changes in ecosystems across the planet.
The review focuses on a central challenge for the Kunming–Montreal Global Biodiversity Framework (GBF): how countries can consistently measure and report on the state of biodiversity across large and often inaccessible regions.
Tropical forests are highlighted as a critical case study. They contain a disproportionate share of global biodiversity, deliver essential nature contributions to people, and are increasingly affected by climate change, land-use change and disturbance.
The authors show that remote sensing is becoming increasingly important for monitoring aspects of forest structure, biomass, canopy traits and ecosystem functioning. These data allow researchers to assess how forests resist, recover from and adapt to environmental change — key components of ecosystem resilience.
The review also notes that satellite data can provide indirect indicators, or “proxies”, for different dimensions of biodiversity, including functional and taxonomic diversity, and to a more limited extent phylogenetic and genetic diversity. These links are increasingly relevant to biodiversity monitoring frameworks such as Essential Biodiversity Variables.
However, the authors emphasise that remote sensing cannot yet provide a complete picture of biodiversity. Many important dimensions — including species turnover, evolutionary history and genetic diversity — remain difficult to observe directly from space and continue to rely on field-based measurements.
They therefore stress that satellite observations must be integrated with ground-based ecology to produce robust and reliable biodiversity assessments.
Looking ahead, the study highlights that next-generation satellite missions and improved sensor technologies, including hyperspectral imaging, LiDAR and radar systems, are expected to significantly expand what can be measured from space in the coming years.
The research is led by Dr Jesús Aguirre-Gutiérrez, Associate Professor and Group Lead of Biodiversity and Earth Observation at the University of Oxford’s Environmental Change Institute (ECI), and also Associate Professor and NERC Independent Research Fellowship (IRF) based at Imperial College London where he leads the Biodiversity & Remote Sensing Lab.
Dr Aguirre-Gutiérrez said:
“Remote sensing is transforming how we can observe biodiversity and ecosystem change at large scales. Satellites now provide unprecedented information on forest structure and function, helping us understand how ecosystems respond to disturbance.
“However, this is not a complete solution. Many dimensions of biodiversity are still difficult to observe directly from space, which is why combining satellite data with field observations remains essential. Future satellite missions will continue to expand what we can measure, but biodiversity monitoring will always depend on integrating multiple sources of evidence.”
Co-authors include researchers from the University of Oxford and international partners across the UK, Mexico, the USA, South Africa and Japan.
The authors conclude that while satellite technologies are rapidly improving the ability to observe and track ecosystems globally, effective biodiversity monitoring under the Global Biodiversity Framework will depend on combining remote sensing with field ecology and emerging biodiversity data frameworks.
Notes to Editors
Background on biodiversity and monitoring
Tropical forests contain around 50% of the world’s terrestrial biodiversity, despite covering only a small fraction of the Earth’s surface.
Forests cover approximately 31% of global land area and play a major role in regulating climate and ecosystem processes.
The Kunming–Montreal Global Biodiversity Framework (GBF) includes the global goal of conserving 30% of land and sea by 2030 (“30x30”).
Biodiversity is multi-dimensional, including species (taxonomic), functional, genetic and evolutionary diversity, many of which are not directly observable from space.
Why remote sensing matters
Satellite Earth observation now provides near-continuous global coverage, enabling consistent monitoring across regions that are difficult to access on the ground.
Recent advances in sensors (e.g. LiDAR, hyperspectral imaging and radar) are expanding the range of ecosystem properties that can be observed, including forest structure and biomass.
Despite this, species-level and genetic diversity cannot yet be directly measured from space at scale, meaning field data remain essential for calibration and validation.
Policy context
The GBF requires countries to report progress using improved biodiversity indicators, but global biodiversity monitoring systems remain uneven and incomplete, particularly in tropical regions.
Frameworks such as Essential Biodiversity Variables (EBVs) are being developed to standardise how biodiversity is measured across scales and data sources.
Journal
Nature Reviews Biodiversity
Method of Research
Literature review
Subject of Research
Not applicable
Article Title
Remote sensing delivers tropical forest resilience monitoring for the Global Biodiversity Framework
Article Publication Date
8-Jul-2026
New UCF study links microgravity, space radiation to accelerated aging
Findings from College of Medicine Professor Michal Masternak and his team suggest spaceflight stressors may accelerate aging in the liver. This discovery could inform future medical research to understand aging on Earth and protect space travelers.
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UCF Professor Michal Masternak and biomedical sciences doctoral student Md Tanjim Alam compared their research with data collected from astronaut blood samples taken during the NASA Twins Study and Inspiration4 astronauts.
view moreCredit: Photo by UCF College of Medicine.
What happens to the human body in space may help scientists create new anti-aging therapies.
UCF’s Michal Masternak and his team have identified molecular changes in the liver that happen when space travelers experience radiation and microgravity. These changes – that resemble accelerated aging – provide new insight into how prolonged space missions may increase health risks for astronauts and reveal potential targets for therapies that could combat age-related diseases on Earth.
“We focused on the liver because it is one of the major metabolic organs in our body,” says Masternak, professor of medicine and leader of the College of Medicine’s aging and space medicine research efforts. “What we found was that just 24 hours after radiation exposure, there are many genetic changes in the liver that are remarkably similar to what happens during aging. We can assume that if someone were in space much longer, the damage could be much greater.”
The findings were recently published in GeroScience.
Navigating the Science
For their study, UCF researchers and scientists from the U.S. created a simulated deep space environment in the lab. The team exposed animal models to simulated microgravity for 14 days and galactic cosmic radiation and solar particle events at NASA Space Radiation Laboratory trying to mimic the dosage that astronauts would be exposed to during a trip to Mars.
The exposure triggered noticeable and potentially harmful changes in the liver, including increased cellular senescence (aging and decreased cell function), inflammation and fibrosis. Left untreated, these conditions can eventually lead to declining and even failing organ function.
The research team then compared their results with data collected from astronaut blood samples taken during the NASA Twins Study and Inspiration4 astronauts. They saw similar genetic changes in blood.
“We’ve got this raw data from human studies, and they show that some of these changes are similar,” Masternak says. “That tells us we’re identifying useful molecular targets that one day could help protect astronauts during long-duration space missions.”
They also went a step further to see whether the changes could be treated. They identified a group of molecules known as antagomirs that alter several aging and inflammatory genetic pathways by interacting with the body’s microRNA. This system could pinpoint promising future therapies for space travelers.
Understanding Aging in the Space Age
Masternak says the nation’s growing space industry provides a unique opportunity to study aging at an accelerated pace.
“Very often when we study different aging processes, it takes time,” he says. “Even in humans, it’s almost impossible because it would take decades. But if we see some acceleration of aging in space, then we can translate it to human studies. We can observe processes happening much faster, understand them better and eventually use that knowledge to improve health for people here on Earth.”
Those discoveries could eventually lead to therapies that slow age-related diseases, preserve organ function and improve quality of life for everyone as they age.
“Our understanding of aging is very complex,” Masternak says. “Aging isn’t simply wrinkles or cosmetic changes. It’s the gradual and cascading failure of multiple organs and biological systems that happen at the same time. By understanding what starts that process and where it happens, we have a better chance of preventing many diseases before they develop. That is one of the biggest outstanding questions.”
Students Positioned at the Forefront of Space Medicine
College of Medicine students are also benefitting from space medicine research. Biomedical Sciences Ph.D. student Md Tanjim Alam joined Masternak’s laboratory during his biotechnology master’s program after initially planning to study cancer in relation to aging biology. Then he was introduced to space medicine, including processing astronaut samples from commercial space travelers to study how extreme environments affect human biology. That research has inspired him.
“I want to keep exploring the unknown,” Alam says. “I really want to understand how space travel influences human health, particularly its effects on aging and cancer.”
Biotechnology graduate student Sarah S. Siddiqi says the interdisciplinary nature of the research attracted her to the space medicine and aging lab.
“When people think of aging, they think only about elderly populations,” says Siddiqi, who earned her bachelor’s degree as a Burnett Honors Scholar in biomedical sciences. “But we study aging across different stages of life and different environments, including space. I’ll always be focused on improving quality of life. I want to better understand diseases that are increasingly prevalent and find ways to recognize them earlier, before they progress to later stages.”
Funding and Disclosure:
Representing UCF, Natalie Hayslip served as first author, while Sarah Ashiqueali, Xiang Zhu, Ridwan Hussein and Mishfak Mansoor also contributed to the research. Researchers from Rensselaer Polytechnic Institute, Weill Cornell Medicine, Universidade Federal de Pelotas, the University of Pittsburgh and the University of North Carolina at Chapel Hill also contributed.
This work was supported by the National Science Foundation Award Number (FAIN): 2317758(MMM), Ed and Ethel Moore Alzheimer’s Disease Research Program of the Florida Department of Health, Public Health Research, Biomedical Research Program 24A12 (MMM), and the National Science Centre, Poland UMO-2023/51/B/NZ5/00498 (MMM).
Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the awarding agencies.
Journal
GeroScience
Article Title
Space radiation and microgravity as models of accelerated aging: modulation of hepatic miRNA‑TGF‑β networks associated with senescence and fibrosis
From the lab to the moon: New research gets man one step to moon living
University of Delaware researchers are developing materials to build infrastructure on the moon and beyond.
Building material samples from the University of Delaware spent six months mounted outside of the International Space Station, where the harsh conditions of low Earth orbit tested their limits.
Some returned with higher measured strength than identical samples stored on Earth. The findings are a promising sign for the long-term goal of building infrastructure on the moon. There are no lunar supply yards, and transporting building materials from Earth would be prohibitively expensive. The solution may lie underfoot, in the form of lunar dust known as regolith.
“Regolith is essentially a clay-like silicate material,” said Norman Wagner, Unidel Robert L. Pigford Chair in Chemical Engineering. “It is one of the most abundant materials on both Earth and the moon, which makes it interesting for construction.”
Wagner's laboratory develops geopolymers, a cement alternative that binds clays into a strong solid through chemical reactions rather than high-temperature manufacturing. Their goal is to use regolith with minimal additives to produce construction materials without energy-intensive processing. The approach could contribute to more sustainable Earth-based construction, too.
To evaluate how geopolymers hold up in space, the UD team sent thin plates made from commercially available simulated lunar and Martian regolith to the International Space Station as part of NASA's MISSE-20 mission.
The findings, published in Advances in Space Research, showed the geopolymers did not deteriorate, and in some cases were stronger after their time in orbit.
Lunar construction materials must not only survive space conditions, they also must be reliably manufactured on-site. In a separate study in Acta Astronautica, Wagner's team used artificial intelligence to tackle a practical challenge: not all lunar clays are the same. The researchers developed a machine learning model that can predict how strong a geopolymer will be based on the characteristics of the starting regolith and how it is processed.
Complementary work from the Wagner lab offers insight into how geopolymers behave while being mixed, pumped and shaped before they harden. The researchers identified a key transition point, known as the critical gel point, at which the material shifts from a workable slurry into a solidifying structure. Mixing or shearing before that point did not affect how long the material took to harden or its final strength. This suggests that engineers may have flexibility in how they handle and process lunar construction materials, without compromising quality.
That work appears in a special issue of the Journal of Rheology focused on materials behavior beyond Earth.
To speak with Wagner about his space expertise, reach out to mediarelations@udel.edu.
Journal
Advances in Space Research
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Effects of low-earth orbit exposure on geopolymer material properties
Korea Astronomy and Space Science Institute increases investment in Giant Magellan Telescope
Multi-million-dollar investment advances scientific instrument development and supports critical milestone toward completion of one of the world's most powerful telescopes
image:
Jang-Hyun Park (left, KASI President) and Daniel Jaffe (GMTO President) meet in KASI presidential office.
view moreCredit: Damien Jemison, Giant Magellan Telescope - GMTO Corporation
PASADENA, CA - July 7, 2026 — The Korea Astronomy and Space Science Institute (KASI) has reaffirmed its long-term commitment to the Giant Magellan Telescope through a new investment that brings its total contribution to nearly $110 million (USD), strengthening the Republic of Korea’s leadership as the project’s third-largest partner.
“The Giant Magellan Telescope is one of the world’s most ambitious research facilities and represents the very best of international scientific collaboration,” said Jang-Hyun Park, president of KASI. “Our participation in the observatory is a cornerstone of South Korea’s long-term astronomy and space science strategy, and our new investment will advance the development of the world’s most advanced scientific instruments to ensure our scientists continue to play a leading role in ground-based and space-based astronomy for generations to come.”
The multi-million-dollar investment will help keep the observatory on the critical path through the U.S. National Science Foundation’s (NSF) Major Facilities Final Design Phase, which began in June 2025 and is scheduled to conclude in 2027. The Republic of Korea and the international consortium building the telescope elected to privately fund the phase, which is traditionally supported by the NSF.
“KASI has played a leading role in advancing the Giant Magellan Telescope since joining the project in 2009,” said Taft Armandroff, board chair of the Giant Magellan Telescope. “Today, the institution is the project’s third-largest partner and continues to shape the observatory’s future. KASI’s additional investment comes at a critical time in the project’s history, enabling our international consortium to privately fund a significant portion of the cost required to complete the NSF Major Facilities Final Design Phase. Their long-term commitment reflects a shared vision to push the boundaries of discovery and ensure scientists around the world have access to one of the most powerful telescopes in history.”
KASI is a contributing partner in the development of several of the Giant Magellan Telescope’s scientific instruments, helping position the observatory to answer some of the most profound questions in modern astronomy, including whether life exists beyond Earth and how the first stars and galaxies formed. The institution’s investment will advance the design and development of the following instruments:
- G-CLEF (GMT-Consortium Large Earth Finder), a high-resolution spectrograph designed to detect and characterize Earth-like planets orbiting nearby stars.
- GMTNIRS (GMT Near-Infrared Spectrograph), a near- to mid-infrared echelle spectrograph designed to study the earliest galaxies in the Universe and the formation of planetary systems.
The Giant Magellan Telescope is under development in Chile’s Atacama Desert, one of the best locations on Earth for ground-based astronomy. The region’s high altitude, extreme dryness, atmospheric stability, and dark skies create observing conditions that cannot be replicated by technology alone. From this Southern Hemisphere location, astronomers gain access to some of the Universe’s most important targets, including the center of the Milky Way, the nearest star to our Sun, and many of the closest galaxies and potentially habitable exoplanets.
Chile’s leadership in astronomy is built not only on geography but also on decades of investment in scientific institutions, international collaboration, and a world-class research community. Together, these advantages have made Chile home to many of the world’s most advanced observatories, including the recently commissioned Vera C. Rubin Observatory, of which KASI is an international partner.
“The skies above Chile are considered one of the best in the world for astronomical research and through international collaboration Chile has promoted the installation of important and visionary projects among them the Giant Magellan Telescope,” said Mathias Francke Schnarbach, Ambassador of Chile to the Republic of Korea. “It is expected that, over the next decade, Chile will account for approximately 75% of the world’s astronomical observation capacity. The growing participation of Korea, through the Korea Astronomy and Space Science Institute, in some of those major international projects in Chile, including the Giant Magellan Telescope and Vera C. Rubin Observatory, will contribute to strengthening and advancing the development of astronomical sciences in both countries.”
For KASI, participation in the Giant Magellan Telescope is part of South Korea’s long-term strategy to gain access to the next generation of research facilities known as “extremely large telescopes,” or ELTs. These ground-based observatories will have five times the light-collecting area and up to 200 times the power of today’s leading telescopes, enabling astronomers to push the boundaries of discovery and maximize the scientific return of future space-based missions. At the same time, KASI’s contributions to the Giant Magellan Telescope’s advanced instrumentation program are cultivating the technical expertise, engineering capabilities, and scientific workforce needed to support South Korea’s next generation of astronomy and space initiatives led by the Korea AeroSpace Administration (KASA).
KASI’s renewed investment reflects the growing international momentum behind the Giant Magellan Telescope and underscores the critical role global partnerships play in advancing humanity’s understanding of the Universe.
