, an assistant professor of astronomy and astrophysics at the University of Warwick who led an international team of researchers to study the object, said in a
.
"These images give us the clearest picture yet of Pa 30's structure, and it's not what we expected," said Cunningham, whose team published their findings in The Astrophysical Journal. "The filaments are made of chains of tiny knots rather than smooth streaks, providing new constraints on the nature of the space around the star before it exploded and the physical processes that have shaped the expanding ejecta."
The knot-like structures may have resulted from variations in temperature or density in material surrounding the star as debris from the explosion expanded.
Pa 30 contains another unusual feature: a surviving star that sits almost exactly at the center of the remnant. That's highly unusual, because a supernova explosion typically sends stars away from their original positions. It suggests that the original explosion was highly symmetrical, the researchers said.
Furthermore, Pa 30 is thought to be a Type Iax supernova. Unlike standard Type Ia supernovas, which destroy their stars, a Type Iax event is a lower-energy, incomplete explosion of a white dwarf star that can leave behind a remnant known as a "zombie star." It's the only Type Iax supernova ever found.
A calculated hunter
Cuttlefish are visual hunters, using their large, complex eyes to locate and track potential meals. In general, their strategy involves a slow, stealthy approach, said Bret Grasse, the manager of cephalopod operations at the Marine Biological Laboratory in Woods Hole Massachusetts.
"The cuttlefish will slowly approach the prey so as to not alert the unsuspecting shrimp, fish or crab," Grasse told Live Science in an email.
During their approach, cuttlefish often put on a showy display, producing moving bands across their body. These displays are produced by a combination of light-reflecting pigment cells known as iridophores, leucophores and chromatophores. These cell types contract and expand to produce specific colors and patterns, all within milliseconds.
Some may wonder whether this trick can mesmerize prey, but scientists don't think that's the case.
Hypnosis, defined as a mental state of increased relaxation and altered awareness, is thought to be a uniquely human psychological state. There is very little research on whether fish can be hypnotized, but a 2005 study found that pushing a steady stream of water through the snapper (Chrysophrys auratus) put them in an immobile state similar to being hypnotized. Another study looked at sedative hypnotic drugs like benzodiazepines and barbiturates and their effects on zebrafish, finding that the fish had molecular receptors for these drugs, which helped render them immobile. However, whether fish can be visually put into a state like hypnosis has yet to be directly studied.
And while some animals, such as chickens, can be induced into trance-like conditions of tonic immobility, an involuntary, temporary state of unresponsiveness that happens when humans or animals experience extreme trauma, it's unlikely that the cuttlefish's color changes "hypnotize" their prey, Connor Gibbons, the cephalopod facility manager at Columbia University told Live Science. Instead, some researchers believe that the color show serves as an ingenious disguise.
As waves of different colors ripple down the cuttlefish's body, the shape of the animal becomes less obvious to its prey, so they may not see the cuttlefish as a threat to flee from, Gibbons said.
"It's only part of something looming at them, which they're like, 'I don't know if you are a predator? Are you just passing waves? What are you?'" Gibbons said. "And then by that time, it's too late."
A cuttlefish uses its tentacles to capture a shrimp (Image credit: Oxford Scientific Films via Getty Images)Once they get close enough, the cuttlefish shoots their two long, specialized feeding tentacles from small hidden pouches near the animal's mouth at their prey.
"The closest thing I can compare it to is the tongue of a chameleon extending out to grab an unsuspecting insect," Grasse said. "Cuttlefish feeding tentacles will fire out in the blink of an eye before the prey can react and escape."
Then, the prey is pulled toward the cuttlefish's mouth, pierced by its sharp, chitinous beak and injected with venom. The use of the venom helps the cuttlefish reduce their energy usage when hunting "as the cuttlefish does not want to use unnecessary energy and struggle against the prey while it's trying to eat," Grasse said.
However, the notion that cuttlefish flash colors to hide their body shape is only one idea of why cuttlefish perform these strobing color displays. Other researchers, including Grasse, describe them as a way to distract their prey.
"Essentially, they are trying their best not to alarm the prey to their presence," he said. By breaking up the size of their bodies, cuttlefish can convince their prey they're not as large or alarming as they may seem.
Whether the light shows are for disguise or distraction still needs parsing out, Gibbons said, and scientists also need a better understanding of how the cuttlefish controls its deadly dermal display. "The jury is still out on exactly what is happening," he said.
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'> Can cuttlefish hypnotize their prey? . In recent decades, their
. But climate change is threatening the health and function of these forests.
"These trees adapted to grow in really temperate environments, so no one had really looked at the impact of heat on photosynthesis," study first author Lily Klinek, a doctoral candidate in the Plant Optics Lab at the University of California, Davis, told Live Science.
From 2022 to 2024, Klinek and colleagues measured how the leaves of redwoods in Garcia River Forest in Mendocino County responded to the heat. Once or twice a month, the researchers took three different California redwood leaf samples and measured their fluorescence and temperature.
The researchers wrapped a fourth leaf in tinfoil for 20 minutes to put it in a state of "rest" before taking the same measurements. "When they're in a state of rest, we expose them to a pulse of light that’s in the wavelength they would use for photosynthesis to see what would be their maximum photosynthetic rate," Klinek said.
They found that on hot days, the leaves exposed to sunlight were up to 18 degrees Fahrenheit (10 degrees Celsius) hotter than the air temperature. "That's a huge difference and indicates that the leaves are stressed to the point where they can't thermoregulate effectively," Klinek said.
Many plants' leaves manage their temperature and photosynthesis by opening or closing their stomata, which are tiny pores on their surface. These stomata (from the Greek word for mouth) regulate the amount of carbon dioxide entering the plant, and how much oxygen and water vapor it releases. Lower carbon dioxide intake leads to reduced photosynthesis, meaning the plant has less energy.
The large differences between air and redwood leaf temperatures suggest that the leaves had closed their stomata to avoid losing water from evaporation during hot conditions and consequently overheated, Klinek said.
To further investigate the impact of heat on leaf physiology, the researchers took California redwood leaf samples back to the laboratory and exposed them to a range of temperatures while they were in water. Despite their access to water, the leaves still photosynthesized less as they got hotter, even though their stomata were open, Klinek said.
This shows that heat imposes direct limitations on redwood photosynthetical capacity, rather than indirectly decreasing that capacity by causing stomatal closure, the researchers wrote. The finding indicates that redwoods' ability to photosynthesise and store carbon will decrease as temperatures rise.
The finding has serious implications for the future of redwoods and similar plants. "The points at which this damage becomes irreversible remains really poorly understood, but is something which is really essential to understand if we want to predict how our future climate is going to impact plants," she said.
The next step in Klinek's research is to move beyond leaf physiology to understand these thresholds on the trees and their ecosystems as a whole.
"We're not sure to what extent the effect that we saw is a reversible stress response and if they are sustaining damage from this constant stress," she said. Researchers need more data to "really get a better sense, beyond the leaf scale, how these ecosystems are responding to heat and drought," she added.
'> California redwoods are struggling in the heat — and it's not clear how much damage is being done