NASA Researchers Probe Tangled Magnetospheres of Merging Neutron Stars - UNIVERSE

New simulations performed on a NASA supercomputer are providing scientists with the most comprehensive look yet into the maelstrom of interacting magnetic structures around city-sized neutron stars in the moments before they crash. The team identified potential signals emitted during the stars’ final moments that may be detectable by future observatories.  

“Just before neutron stars crash, the highly magnetized, plasma-filled regions around them, called magnetospheres, start to interact strongly. We studied the last several orbits before the merger, when the entwined magnetic fields undergo rapid and dramatic changes, and modeled potentially observable high-energy signals,” said lead scientist Dimitrios Skiathas, a graduate student at the University of Patras, Greece, who is conducting research for the Southeastern Universities Research Association in Washington at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

New supercomputer simulations explore the tangled magnetic structures around merging neutron stars. Called magnetospheres, the highly magnetized, plasma-filled regions start to interact as the city-sized stars close on each other toward their final orbits. Magnetic field lines can connect both stars, break, and reconnect, while currents surge through surrounding plasma moving at nearly the speed of light. The simulations show that as these systems merge to produce one kind of gamma-ray burst — the universe’s most powerful class of explosions — they emit tell-tale X-rays and gamma rays that future observatories should be able to detect. NASA’s Goddard Space Flight Center

A paper describing the findings published Nov. 20, 2025, in the The Astrophysical Journal.

Neutron star mergers produce a particular type of GRB (gamma-ray burst), the most powerful class of explosions in the cosmos.

Most investigations have naturally concentrated on the spectacular mergers and their aftermaths, which produce near-light-speed jets that emit gamma rays, ripples in space-time called gravitational waves, and a so-called kilonova explosion that forges heavy elements like gold and platinum. A merger observed in 2017 dramatically confirmed the long-predicted connections between these phenomena — and remains the only event seen so far to exhibit all three.

Neutron stars pack more mass than our Sun into a ball about 15 miles (24 kilometers) across, roughly the length of Manhattan Island in New York City. They form when the core of a massive star runs out of fuel and collapses, crushing the core and triggering a supernova explosion that blasts away the rest of the star. The collapse also revs up the core’s rotation and amplifies its magnetic field.

“In our simulations, the magnetosphere behaves like a magnetic circuit that continually rewires itself as the stars orbit.

Constantinos Kalapotharakos

Newborn neutron stars can spin dozens of times a second and wield some of the strongest magnetic fields known, up to 10 trillion times stronger than a refrigerator magnet. That’s strong enough to directly transform gamma-rays into electrons and positrons and rapidly accelerate them to energies far beyond anything achievable in particle accelerators on Earth. 

“In our simulations, the magnetosphere behaves like a magnetic circuit that continually rewires itself as the stars orbit. Field lines connect, break, and reconnect while currents surge through plasma moving at nearly the speed of light, and the rapidly varying fields can accelerate particles,” said co-author Constantinos Kalapotharakos at NASA Goddard. “Following that nonlinear evolution at high resolution is exactly why we need a supercomputer!”

Using the Pleiades supercomputer at NASA’s Ames Research Center in California’s Silicon Valley, the team ran more than 100 simulations of a system of two orbiting neutron stars, each with 1.4 solar masses. The goal was to explore how different magnetic field configurations affected the way electromagnetic energy — light in all of its forms — left the binary system. Most of the simulations describe the last 7.7 milliseconds before the merger, enabling a detailed study of the final orbits.

“Our work shows that the light emitted by these systems varies greatly in brightness and is not distributed evenly, so a far-away observer’s perspective on the merger matters a great deal,” said co-author Zorawar Wadiasingh at the University of Maryland, College Park and NASA Goddard. “The signals also get much stronger as the stars get closer and closer in a way that depends on the relative magnetic orientations of the neutron stars.”

Magnetic field lines anchored to the surfaces of each star sweep behind them as the stars orbit. Field lines may directly connect one star to the other as the orbits shrink, while lines already linking the stars may break and reconfigure.

“One value of studies like this is to help us figure out what future observatories might be able to see and should be looking for in both gravitational waves and light.

Demosthenes Kazanas

Using the simulations, the team also computed electromagnetic forces acting on the stars’ surfaces. While the effects of gravity dominate, these magnetic stresses could accumulate in strongly magnetized systems. Future models may help reveal how magnetic interactions influence the last moments of the merger.

“Such behavior could be imprinted on gravitational wave signals that would be detectable in next-generation facilities. One value of studies like this is to help us figure out what future observatories might be able to see and should be looking for in both gravitational waves and light,” said Goddard’s Demosthenes Kazanas.

The team, which includes Alice Harding at the Los Alamos National Laboratory in New Mexico and Paul Kolbeck at the University of Washington in Seattle, then used the simulated fields to identify where the highest-energy emission would be produced and how it would propagate.

This view of a supercomputer simulation of merging, magnetized neutron stars highlights regions producing the highest-energy light. Brighter colors indicate stronger emission. These regions produce gamma rays with energies trillions of times greater than that of visible light, but likely none of it could escape. That’s because the highest-energy gamma rays quickly convert to particles in the presence of the stars' powerful magnetic fields. However, gamma rays at lower energies, with millions of times the energy of visible light, can exit the merging system, and the resulting particles may also radiate at still lower energies, including X-rays. The emission varies rapidly and is highly directional, but it could potentially be detected by future facilities.

NASA’s Goddard Space Flight Center/D. Skiathas et al. 2025

In the chaotic plasma surrounding the neutron stars, particles transform into radiation and vice versa. Speedy electrons emit gamma rays, the highest-energy form of light, through a process called curvature radiation. A gamma-ray photon can interact with a strong magnetic field in a way that transforms it into a pair of particles, an electron and a positron.

The study found regions producing gamma rays with energies trillions of times greater than that of visible light, but likely none of it could escape. The highest-energy gamma rays quickly converted to particles in the presence of powerful magnetic fields. However, gamma rays at lower energies, with millions of times the energy of visible light, can exit the merging system, and the resulting particles may also radiate at still lower energies, including X-rays.

The finding suggests that future medium-energy gamma-ray space telescopes, especially those with wide fields of view, may detect signals originating in the runup to the merger if gravitational-wave observatories can provide timely alerts and sky localization. Today, ground-based gravitational-wave observatories, such as LIGO (Laser Interferometer Gravitational-Wave Observatory) in Louisiana and Washington, and Virgo in Italy, detect neutron star mergers with frequencies between 10 and 1,000 hertz and can enable rapid electromagnetic follow-up.

ESA (European Space Agency) and NASA are collaborating on a space-based gravitational-wave observatory named LISA (Laser Interferometer Space Antenna), planned for launch in the 2030s. LISA will observe neutron-star binaries much earlier in their evolution at far lower gravitational-wave frequencies than ground-based observatories, typically long before they merge.

Future gravitational-wave observatories will be able to alert astronomers to systems on the verge of merging. Once such systems are found, wide-field gamma-ray and X-ray observatories could begin searching for the pre-merger emission highlighted by these simulations.

Routine observation of events like these using two different “messengers” — light and gravitational waves — will provide a major leap forward in understanding this class of GRBs, and NASA researchers are helping to lead the way.

By Francis Reddy
NASA’s Goddard Space Flight Center, Greenbelt, Md.  

Source: NASA Researchers Probe Tangled Magnetospheres of Merging Neutron Stars - NASA Science

Organic molecule stores solar energy for years, then releases it as heat on demand - Energy & Green Tech - Hi Tech & Innovation

Credit: NASA

When the sun goes down, solar panels stop working. This is the fundamental hurdle of renewable energy: how to save the sun's power for a rainy day—or a cold night. Chemists at UC Santa Barbara have developed a solution that doesn't require bulky batteries or electrical grids. In a paper published in the journal Science, Associate Professor Grace Han and her team detail a new material that captures sunlight, stores it within chemical bonds and releases it as heat on demand.

The material, a modified organic molecule called pyrimidone, is the latest advancement in molecular solar thermal (MOST) energy storage.

"The concept is reusable and recyclable," said Han Nguyen, a doctoral student in the Han Group and the paper's lead author.

"Think of photochromic sunglasses. When you're inside, they're just clear lenses. You walk out into the sun, and they darken on their own. Come back inside, and the lenses become clear again," Nguyen continued.

"That kind of reversible change is what we're interested in. Only instead of changing color, we want to use the same idea to store energy, release it when we need it, and then reuse the material over and over."

Bio-inspired design

To create this molecule, the team looked to a surprising source: DNA. The pyrimidone structure is similar to a component found in DNA that, when exposed to UV light, can undergo reversible structural changes.

By engineering a synthetic version of this structure, the team created a molecule that stores and releases energy reversibly. They collaborated with Ken Houk, a distinguished research professor at UCLA, to use computational modeling to understand why the molecule was able to store energy and remain stable for years without losing the stored energy.

"We prioritized a lightweight, compact molecule design," Nguyen said. "For this project, we cut everything we didn't need. Anything that was unnecessary, we removed to make the molecule as compact as possible."

A 'rechargeable battery' for heat

Traditional solar panels convert light into electricity; however, most systems convert light into chemical energy. The molecule acts like a mechanical spring: when hit with sunlight, it twists into a strained, high-energy shape. It stays locked in that shape until a trigger—such as a small amount of heat or a catalyst—snaps it back to its relaxed state, releasing the stored energy as heat.

"We typically describe it as a rechargeable solar battery," Nguyen said. "It stores sunlight, and it can be recharged."

The team's new molecule is a heavy hitter. It boasts an energy density of more than 1.6 megajoules per kilogram. That is roughly double the energy density of a standard lithium-ion battery—which comes in at around 0.9 MJ/kg—and significantly higher than previous generations of optical switches.

From theory to boiling water

The critical breakthrough for Han's group was translating high energy density into a tangible result. In the study, the researchers demonstrated that the heat released from the material was intense enough to boil water—a feat previously difficult to achieve in this field.

"Boiling water is an energy-intensive process," Nguyen said. "The fact that we can boil water under ambient conditions is a big achievement."

This capability opens the door for practical applications ranging from off-grid heating for camping to residential water heating. Because the material is soluble in water, it could potentially be pumped through roof-mounted solar collectors to charge during the day and stored in tanks to provide heat at night.

"With solar panels, you need an additional battery system to store the energy," said co-author Benjamin Baker, a doctoral student in the Han Lab. "With molecular solar thermal energy storage, the material itself is able to store that energy from sunlight." 

Provided by University of California - Santa Barbara 

by Seren Snow, University of California - Santa Barbara

edited by Gaby Clark, reviewed by Robert Egan 

Source: Organic molecule stores solar energy for years, then releases it as heat on demand