The research, published in The Astrophysical Journal Letters, could one day help to unlock some of the universe’s deepest mysteries, including how gravity works at its most fundamental level.

“There is a lot we can learn from getting these precise measurements of gravitational waves,” said Darling, professor in the Department of Astrophysical and Planetary Sciences. “Different flavors of gravity could lead to lots of different kinds of gravitational waves.”

To understand how such waves work, it helps to picture Earth as a small buoy bobbing in a stormy ocean.

Darling explained that, throughout the history of the universe, countless supermassive black holes have engaged in a volatile dance: These behemoths spiral around each other faster and faster until they crash together. Scientists suspect that the resulting collisions are so powerful they, literally, generate ripples that spread out into the universe.

This background noise washes over our planet all the time, although you’d never know it. The kinds of gravitational waves that Darling seeks to measure tend to be very slow, passing our planet over the course of years to decades.

In 2023, a team of scientists belonging to the NANOGrav collaboration achieved a coup by measuring that cosmic wave pool. The group recorded how the universe’s gravitational wave background stretched and squeezed spacetime, affecting the light coming to Earth from celestial objects known as pulsars, which act somewhat like cosmic clocks.

But those detailed measurements only captured how gravitational waves move in a single direction — akin to waves flowing directly toward and away from a shoreline. Darling, in contrast, wants to see how gravitational waves also move from side-to-side and up and down compared to Earth.

In his latest study, the astrophysicist got help from another class of celestial objects: quasars, or unusually bright, supermassive black holes sitting at the centers of galaxies. Darling searches for signals from gravitational waves by precisely measuring how quasars move compared to each other in the sky. He hasn’t spotted those signals yet, but that could change as more data become available.

“Gravitational waves operate in three dimensions,” Darling said. “They stretch and squeeze spacetime along our line of sight, but they also cause objects to appear to move back and forth in the sky.”

Galaxies in motion

The research drills down on the notoriously tricky task of studying how celestial objects move, a field known as astrometry.

Darling explained that quasars rest millions of light-years or more from Earth. As the glow from these objects speeds toward Earth, it doesn’t necessarily proceed in a straight line. Instead, passing gravitational waves will deflect that light, almost like a baseball pitcher throwing a curve ball.

Those quasars aren’t actually moving in space, but from Earth, they might look like they are — a sort of cosmic wiggling happening all around us.

“If you lived for millions of years, and you could actually observe these incredibly tiny motions, you’d see these quasars wiggling back and forth,” Darling said.

Or that’s the theory. In practice, scientists have struggled to observe those wiggles. In part, that’s because these motions are hard to observe, requiring a precision 10 times greater than it would take to watch a human fingernail growing on the moon from Earth. But our planet is also moving through space. Our planet orbits the sun at a speed of roughly 67,000 miles per hour, and the sun itself is hurtling through space at a blistering 850,000 miles per hour.

Detecting the signal from gravitational waves, in other words, requires disentangling Earth’s own motion from the apparent motion of quasars. To begin that process, Darling drew on data from the European Space Agency’s Gaia satellite. Since Gaia’s launch in 2013, its science team has released observations of more than a million quasars over about three years.

Darling took those observations, split the quasars into pairs, then carefully measured how those pairs moved relative to each other.

His findings aren’t detailed enough yet to prove that gravitational waves are making quasars wiggle. But, Darling said, it’s an important search — unraveling the physics of gravitational waves, for example, could help scientists understand how galaxies evolve in our universe and help them test fundamental assumptions about gravity.

The astrophysicist could get some help in that pursuit soon. In 2026, the Gaia team plans to release five-and-a-half more years of quasar observations, providing a new trove of data that might just reveal the secrets of the universe’s gravitational wave background.

“If we can see millions of quasars, then maybe we can find these signals buried in that very large dataset,” he said.

But where there is water, there are waterbirds. Little is known about the impacts — positive or negative — floating solar projects may have on birds and other wildlife. A paper from the University of California, Davis, published in the journal Nature Water, is among the first to outline key considerations to better align renewable energy and biodiversity goals.

Birds face many threats — from habitat loss and climate change to pollution and avian influenza — and many populations are in decline.

“That’s why it’s so important to understand how waterbirds are going to respond to floating solar and if there is the possibility for conservation concessions at new floating solar facilities,” said corresponding author Elliott Steele, a postdoctoral scholar with the UC Davis Wild Energy Center within the Energy and Efficiency Institute. “We want to advance clean energy while promoting healthy, functional environments. Achieving this balance requires that we rigorously study and understand how wildlife responds to floating solar so we can ensure that negative impacts are avoided and potential ecological benefits are realized.”

Five considerations

Drawing from their scientific field observations of birds interacting with floating PV systems, the authors examined various ways such systems could impact birds, and vice versa. They concluded that future research on FPV-waterbirds interactions should examine:

• How waterbirds interact with each part of the floating PV infrastructure.
• The direct and indirect effects waterbirds and floating solar projects may have on each other.
• How bird conservation strategies may vary by site, region or season.
• How to best monitor waterbirds at floating solar sites.
• The potential for pollutants to be released or leached from floating solar infrastructure and what can be done to mitigate risks.

“Our team has been documenting such a diversity of bird behavior with floating PV, so we immediately knew this was a very important interaction, especially given the precipitous decline in waterbird numbers globally,” said senior author and UC Davis Professor Rebecca R. Hernandez, director of the UC Davis Wild Energy Center. “Humans are also responding to waterbirds on floating PV, sometimes with deterrence. We leveraged our team’s expertise in ecology and energy system science to identify risks and solution pathways such that waterbirds and floating PV can coexist.”

Critical threshold of development

The Wild Energy Center is conducting research to begin to answer some of those questions. During their field work, the authors have seen black-crowned night herons resting on a floating solar structure before dawn, double-breasted cormorants jockeying for a favorable site, black phoebes nesting under panels, and more.

They note that while many types of wildlife use artificial water bodies, the authors focused on waterbirds because they interact above and below floating solar panels and are easy to observe.

So far, the scientists have observed mostly positive waterbird interactions with floating solar and additional benefits for people. For example, a farm that installs floating solar over an irrigation pond can save water by reducing evaporation, as well as produce clean energy without taking up cropland. Yet more research is required to fully understand the risks and benefits of introducing a large, relatively new technology into an aquatic environment.

“There are some things we wished we’d known before other kinds of renewable energy were developed,” said coauthor Emma Forester, a Ph.D. candidate with the UC Davis Land, Air and Water Resources department and the Wild Energy Center. “While we’re at this critical threshold of renewable energy development, we want to put more thought into the design that can benefit birds and other wildlife as we go forward.”

Additional coauthors include Alexander Cagle and Jocelyn Rodriguez of UC Davis, Tara Conkling and Todd Katzner of U.S. Geological Survey, Sandor Kelly of University of Central Florida, Giles Exley and Alona Armstrong of Lancaster University, and Giulia Pasquale and Miriam Lucia Vincenza Di Blasi of Innovation of Enel Green Power in Italy.

The study was funded by the UC Office of the President’s California Climate Action Seed Grant, Enel Green Power, U.S. Department of Energy, U.S. Bureau of Land Management and U.S. Geological Survey.

The team at WEHI in Melbourne, Australia, have identified a small molecule that can selectively block cell death.

Published in Science Advances, the findings lay the groundwork for next-generation neuroprotective drugs for degenerative conditions, which currently have no cure or treatments to stop their progression.

At a glance

• Researchers have discovered how to block cell death, an important first step towards slowing neurodegenerative conditions.

• The study from team at WEHI, including researchers from the Parkinson’s Disease Research Centre, has revealed new insight into the mechanisms behind cell death and how it is controlled.

• The discovery was made possible through the advanced screening technologies of the National Drug Discovery Centre.

A new hope in the fight against degenerative conditions

Millions of cells are programmed to die in our bodies every day. But excessive cell death can cause degenerative conditions including Parkinson’s disease and Alzheimer’s disease, with the premature death of brain cells a cause of symptoms in these diseases.

Professor Grant Dewson, co-corresponding author and head of the WEHI Parkinson’s Disease Research Centre, said: “Currently there are no treatments that prevent neurons from dying to slow the progression of Parkinson’s. Any drugs that could be able to do this could be game changing.”

The new study aimed to find new chemicals that block cell death and could be useful to treat degenerative diseases in the future.

To identify novel small molecules, the team worked with researchers in the National Drug Discovery Centre, headquartered at WEHI.

A high-throughput screen of over 100,000 chemical compounds identified one that was effective at stopping cells from dying, by interfering with a well-understood cell death protein.

Co-corresponding author Professor Guillaume Lessene said: “We were thrilled to find a small molecule that targets a killer protein called BAX and stops it working.

“While not the case in most cells, in neurons turning off BAX alone may be sufficient to limit cell death.”

Building on decades of pioneering cell death research

The new research builds on decades of world-leading WEHI discoveries in cell death. A pioneering discovery at WEHI in 1988 of a protein that stopped programmed cell death sparked huge interest in the field, and has since led to a new drug to treat cancer.

While drugs that trigger cell death are transforming treatment of certain cancers, the development of cell death blockers — that could be similarly game-changing for neurodegenerative conditions — has proven challenging.

The new molecule targets a killer protein called BAX which kills cells by damaging mitochondria, the powerhouse of cells.

Lead author and Dewson Lab researcher Kaiming Li said: “For the first time we could keep BAX away from mitochondria and keep cells alive using this molecule.

“This could pave the way for next-generation cell death inhibitors to combat degenerative conditions.”

The study demonstrates the potential to identify drugs that block cell death and may open a new avenue to find much-needed disease-modifying drugs for neurodegenerative conditions such as Parkinson’s and Alzheimer’s.

The WEHI Parkinson’s Disease Research Centre is focusing on its expertise in cell death, ubiquitin signalling, mitochondria and inflammation in the hunt for disease-modifying therapies for Parkinson’s.

By using a multidisciplinary approach to build understanding of the mechanisms behind the disease, the centre hopes to accelerate the discovery of drugs to stop disease progression, transforming the lives of those living with the condition.

The new research was supported by the Bodhi Education Fund and the National Health and Medical Research Council.