Weird Signals from Space Are ‘Unlike Any Known Galactic Object’

Welcome back to the Abstract! 

This week, scientists accidentally discovered a weird thing in space that is like nothing we have ever seen before. This happens a lot, yet never seems to get old. 

Then, a shark banquet, the Ladies Anuran Choir, and yet another reason to side-eye shiftwork. Last, a story about the importance of finishing touches for all life on Earth (and elsewhere).

Dead Stars Still Get Hyped

Wang, Ziteng et al. “Detection of X-ray emission from a bright long-period radio transient.” Nature.

I love a good case of scientific serendipity, and this week delivered with a story about a dead star with the cumbersome name ASKAP J1832−0911. 

The object, which is located about 15,000 light years from Earth, was first spotted flashing in radio every 44 minutes by the wide-field Australian Square Kilometre Array Pathfinder (ASKAP). By a stroke of luck, NASA’s Chandra X-ray Observatory, which has a very narrow field-of-view, happened to be pointed the same way, allowing follow-up observations of high-energy X-ray pulses synced to the same 44-minute cycle.  

This strange entity belongs to a new class of objects called long-period radio transients (LPTs) that pulse on timescales of minutes and hours, distinguishing them from pulsars, another class of dead stars with much shorter periods that last seconds, or milliseconds. It is the first known LPT to produce X-ray pulses, a discovery that could help unravel their mysterious origin. 

ASKAP J1832−0911 exhibits “correlated and highly variable X-ray and radio luminosities, combined with other observational properties, [that] are unlike any known Galactic object,” said researchers led by Ziteng Wang of Curtin University. “This X-ray detection from an LPT reveals that these objects are more energetic than previously thought.”

It’s tempting to look at these clockwork signals and imagine advanced alien civilizations beaming out missives across the galactic transom. Indeed, when astronomer Jocelyn Bell discovered the first pulsar in 1967, she nicknamed it Little Green Men (LGM-1) to acknowledge this outside possibility. But dead stars can have just as much rhythm as (speculative) live aliens. Some neutron stars, like pulsars, flash with precision similar to atomic clocks. These pulses are either driven by the extreme dynamics within the dead stars, or orbital interactions between a dead star and a companion star.

Wang and his colleagues speculate that ASKAP J1832−0911 is either “an old magnetar” (a type of pulsar) or an “ultra-magnetized white dwarf” though the team adds that “both interpretations present theoretical challenges.” Whatever its nature, this stellar corpse is clearly spewing out tons of energetic radiation during “hyper-active” phases, hinting that other LPTs might occasionally get hyped enough to produce X-rays.

“The discovery of X-ray emission from ASKAP J1832−0911 raises the exciting possibility that some LPTs are more energetic objects emitting X-rays,” the team said. “Rapid multiwavelength follow-up observations of ASKAP J1832−0911 and other LPTs, will be crucial in determining the nature of these sources.”

Rotting Whale Carcass, Served Family-Style 

Scott, Molly et al. “Novel observations of an oceanic whitetip (Carcharhinus longimanus) and tiger shark (Galeocerdo cuvier) scavenging event.” Frontiers in Fish Science.

On April 9, 2024, scientists spent nearly nine hours watching a bunch of sharks feed on a giant chunk of dead whale floating off the coast of Kailua-Kona, Hawaii, which is a pretty cool item in  a job description. The team has now published a full account of the feast, attended by a dozen whitetip and tiger sharks, which sounds vaguely reminiscent of a cruise-ship cafeteria. 

Yum. Image: Scott, Molly et al.

“Individuals from both species filtered in and out of the scene, intermittently feeding either directly on the carcass or on fallen scraps,” said researchers led by Molly Scott of the University of Hawaii at Manoa. “Throughout this time, it did not appear that any individual reached a point of satiation and permanently left the area; rather, they stayed, loitering around the carcass and intermittently feeding.” 

All the Ladies in the House Say RIBBIT

Santana, Erika et al. “The ‘silent’ half: diversity, function and the critical knowledge gap on female frog vocalizations.” Proceedings of the Royal Society B.

Shout out to the toadettes—we hear you, even if nobody else does. Female anurans (the group that contains frogs and toads) are a lot more soft-spoken than their extremely vocal male conspecifics. This has led to “a male-biased perspective in anuran bioacoustics,” according to a new study that identified and analyzed female calls in more than 100 anuran species.

“It is unclear whether female calls influence mate attraction, whether males discriminate among calling females, or whether female–female competition occurs in species where females produce advertisement calls or aggressive calls,” said researchers led by Erika Santana of Universidade de São Paulo. “This review provides an overview of female calling behaviour in anurans, addressing a critical gap in frog bioacoustics and sexual selection.”

The Reason for the Season(al Affective Disorders)

Kim, Ruby et al. “Seasonal timing and interindividual differences in shiftwork adaptation.” NPJ Digital Medicine.

Why are you tired all the time? It’s the perennial question of our age (and many previous ones). One factor may be that our ancient sense of seasonality is getting thrown off by modern shiftwork, according to a study that tracked the step count, heart rate, and sleep patterns of more than 3,000 medical residents in the U.S. with wearable devices for a year.

“We show that there is a relationship between seasonal timing and shiftwork adaptation, but the relationship is not straightforward and can be influenced by many other external factors,” said researchers led by Ruby Kim of the University of Michigan. 

“We find that a conserved biological system of morning and evening oscillators, which evolved for seasonal timing, may contribute to these interindividual differences,” the team concluded. “These insights highlight the need for personalized strategies in managing shift work to mitigate potential health risks associated with circadian disruption.”

In short, blame that afternoon slump on an infinity of ancestral seasons past. 

Finishing Touches on a Planet

Marchi, Simone et al. “The shaping of terrestrial planets by late accretions.” Nature.

Earth wasn’t finished in a day; in fact, it took anywhere from 60 to 100 million years for 99 percent of our planet to coalesce from debris in the solar nebula. But the final touch—that last 1 percent—is disproportionately critical to the future of rocky planets like our own. That’s the conclusion of a study that zooms in on the bumpy phase called “late accretion,” which often involves global magma oceans and bombardment from asteroids and comets.

“Late accretion may have been responsible for shaping Earth’s distinctive geophysical and chemical properties and generating pathways conducive to prebiotic chemistry,” said researchers led by Simone Marchi of the Southwest Research Institute and Jun Korenaga of Yale University. “The search for an Earth’s twin may require finding rocky planets not only with similar bulk properties…but also with similar collisional evolution in their late accretions.”

Thanks for reading! See you next week.