An international team led by researchers from the University of Adelaide and the University of Copenhagen reconstructed an 11,700-year ecological baseline for bowhead whales, which are a threatened Arctic native species.

Using computer models, fossils, and whaling records, the team mapped the location and size of suitable summer foraging habitat for bowhead whales over the entire Holocene, finding that until recently it remained constant despite significant climatic fluctuations.

However, they predict that future climate change will erode somewhere between 65-75 per cent of this foraging habitat by the end of the 21st century. In the Sea of Okhotsk, which is home to one of only four populations of bowhead whales, viable summer habitat is likely to vanish entirely by 2060.

The reason for the decline is the collapse of a tight association between bowhead whales and summer sea ice cover.

“Bowhead whales have preferred to forage amongst sea ice for many millennia,” said lead author Mr Nicholas Freymueller, from the University of Adelaide’s Environment Institute and the University of Copenhagen’s Globe Institute.

“However, Arctic sea ice has declined significantly in recent decades, and this is set to accelerate in coming decades, causing habitats where bowhead whales currently congregate in large numbers to be lost.”

The team also found that the few patches of suitable bowhead habitat predicted to remain in the year 2100 will exist outside their current distribution, directly impacting conservation policies.

“By identifying the extent and location of bowhead whale habitat that is likely to be lost in coming decades, our projections provide vital information to guide future management efforts of this emblematic species,” said Professor Eline Lorenzen, from the University of Copenhagen’s Globe Institute.

Bowhead whales are still recovering from four centuries of commercial whaling. They are considered emblematic because the ongoing threats they face are reflective of those which all Arctic marine mammal species face due to climate change.

“By using ecological models and paleo-archives to reconstruct pre-whaling distributions of bowhead whales, we were able to develop a much stronger understanding of the habitat preferences of this species that was nearly hunted to extinction,” said senior author Associate Professor Damien Fordham, from the University of Adelaide’s Environment Institute.

“This gives us improved confidence in our projections of habitat loss.”

The study, published in Ecology and Evolution, shows how past perspectives can strengthen predictions of species’ future vulnerability to rapid ocean warming.

Some spiral galaxies, including the Milky Way, exhibit a straight bar inside the spiral pattern. This bar structure helps channel gas towards the center of the galaxy where it can be used to form new stars. But why bars form in only about half of spiral galaxies, and how they influence the evolution of the galaxy are unanswered questions.

To study the evolution of spiral galaxies in the early Universe, researchers led by Shuo Huang, a project researcher at the National Astronomical Observatory of Japan and Nagoya University, used the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope to observe a massive barred spiral galaxy known as J0107a that existed 11.1 billion years ago. Located in the constellation Cetus, J0107a is a “monster” galaxy, meaning a galaxy growing rapidly in the early Universe by forming many new stars. Because they are located far away, it has been difficult to see the detailed structure of monster galaxies and determine what is driving this vigorous star formation. Recently the improved resolution provided by the James Webb Space Telescope has revealed spirals and even bars in some of the monster galaxies. J0107a is the earliest and most massive barred spiral galaxy known to date, so it is the best target for studying the evolution of barred spiral galaxies in the early Universe.

The team found that in J0107a the distribution and motion of gas in the bar is similar to modern galaxies. But compared to modern galaxies, the concentrations of gas are several times higher and the speed of the gas flow is faster, reaching several hundred kilometers per second. Astronomers believe that this massive influx of gas to the center will fuel signification additional star formation, helping to drive the evolution of this monster galaxy. This is the first time these features have been observed, and they were not predicted by theoretical or simulation models.

Huang comments, “We expect that the detailed information about the distribution and movement of gas gained through these observations will provide important clues for exploring not only the origins of the diversity of galaxies, but also the formation and evolution of more normal barred spiral galaxies.”

By analysing data from the Cassini-Huygens mission, a joint venture between NASA, the European Space Agency (ESA), and the Italian Space Agency, the team have shown that the thick, hazy atmosphere of Saturn’s largest moon doesn’t spin in line with its surface, but instead wobbles like a gyroscope, shifting with the seasons.

Titan is the only moon in the Solar System with a significant atmosphere, and one that has long captivated planetary scientists. Now, after 13 years of thermal infrared observations from Cassini, researchers have tracked how Titan’s atmosphere tilts and shifts over time.

“The behaviour of Titan’s atmospheric tilt is very strange!” said Lucy Wright, lead author and postdoctoral researcher at Bristol’s School of Earth Sciences. “Titan’s atmosphere appears to be acting like a gyroscope, stabilising itself in space.

“We think some event in the past may have knocked the atmosphere off its spin axis, causing it to wobble.

“Even more intriguingly, we’ve found that the size of this tilt changes with Titan’s seasons.”

The team studied the symmetry of Titan’s atmospheric temperature field and found that it isn’t centred exactly on the pole, as expected. Instead, it shifts over time, in step with Titan’s long seasonal cycle — each year on Titan lasts nearly 30 years on Earth.

Professor Nick Teanby, co-author and planetary scientist at Bristol said: “What’s puzzling is how the tilt direction remains fixed in space, rather than being influenced by the Sun or Saturn.

“That would’ve given us clues to the cause. Instead, we’ve got a new mystery on our hands.”

This discovery will impact NASA’s upcoming Dragonfly mission, a drone-like rotorcraft scheduled to arrive at Titan in the 2030s. As Dragonfly descends through the atmosphere, it will be carried by Titan’s fast-moving winds — winds that are about 20 times faster than the rotation of the surface.

Understanding how the atmosphere wobbles with the seasons is crucial for calculating the landing trajectory of Dragonfly. The tilt affects how the payload will be carried through the air, so this research can help engineers better predict where it will touch down.

Dr Conor Nixon, planetary scientist at NASA Goddard and co-author of the study, added: “Our work shows that there are still remarkable discoveries to be made in Cassini’s archive.

“This instrument, partly built in the UK, journeyed across the Solar System and continues to give us valuable scientific returns.

“The fact that Titan’s atmosphere behaves like a spinning top disconnected from its surface raises fascinating questions — not just for Titan, but for understanding atmospheric physics more broadly, including on Earth.”

The team’s findings contribute to a growing body of research suggesting Titan is not just Earth-like in appearance but an alien world with climate systems all its own, and many secrets still hidden beneath its golden haze.

Holograms are not only used as fun-to-look-at safety stickers on credit cards, electronic products or banknotes; they have scientific applications in sensors and in microscopy as well. Traditionally, holograms require a laser for recording, but more recently, techniques that can record holograms with ambient light or light emanating from a sample have been developed. There are two main techniques that can achieve this: one is called “FINCH” and uses a 2D image sensor that is fast enough to record movies, but is limited to visible light and an unobstructed view, while the other is called “OSH,” which uses a one-pixel sensor and can record through scattering media and with light outside the visual spectrum, but can only practically record images of motionless objects.

Kobe University applied optics researcher YONEDA Naru wanted to create a holographic recording technique that combines the best of both worlds. To tackle the speed-limiting weak point of OSH, he and his team constructed a setup that uses a high-speed “digital micromirror device” to project onto the object the patterns that are required for recording the hologram. “This device operates at 22 kHz, whereas previously used devices have a refresh rate of 60 Hz. This is a speed difference that’s equivalent to the difference between an old person taking a relaxed stroll and a Japanese bullet train,” Yoneda explains.

In the journal Optics Express, the Kobe University team now publish the results of their proof-of-concept experiments. They show that their setup can not only record 3D images of moving objects, but they could also construct a microscope that can record a holographic movie through a light-scattering object — a mouse skull to be precise.

Admittedly, the frame rate of just over one frame per second was still fairly low. But Yoneda and his team showed in calculations that they could in theory get that frame rate up to 30 Hz, which is a standard screen frame rate. This would be achieved through a compression technique called “sparse sampling,” which works by not recording every portion of the picture all the time.

So, where will we be able to see such a hologram? Yoneda says: “We expect this to be applied to minimally invasive, three-dimensional biological observation, because it can visualize objects moving behind a scattering medium. But there are still obstacles to overcome. We need to increase the number of sampling points, and also the image quality. For that, we are now trying to optimize the patterns we project onto the samples and to use deep-learning algorithms for transforming the raw data into an image.”

This research was funded by the Kawanishi Memorial ShinMaywa Education Foundation, the Japan Society for the Promotion of Science (grants 20H05886, 23K13680), the Agencia Estatal de Investigación (grant PID2022-142907OB-I00) and the European Regional Development Fund, and the Generalitat Valenciana (grant CIPROM/2023/44). It was conducted in collaboration with researchers from Universitat Jaume I.