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Teaching a goldfish to drive

Israeli scientists have taught a goldfish how to drive, and it’s probably the best thing you’ll see all week. Here at Cosmos, we’re already fairly certain that the video is going to make our top 10 science videos of the year.

Researchers at Ben-Gurion University of the Negev built a “car” that could house the goldfish’s tank. The vehicle was equipped with a camera, which recorded the fish’s movements and translated them into directions to move the vehicle around. As the fish moved around the tank in pursuit of food rewards, the vehicle trundled around.

This set-up was used to study the fish’s navigational abilities.

“The study hints that navigational ability is universal rather than specific to the environment,” says Shachar Givon, a co-author of the study in Behavioural Brain Research.

“Second, it shows that goldfish have the cognitive ability to learn a complex task in an environment completely unlike the one they evolved in. As anyone who has tried to learn how to ride a bike or to drive a car knows, it is challenging at first.”

New solution for magnetic mystery

When the Apollo program touched down on the Moon in the late 1960s and early 1970s, astronauts collected rock samples for analysis back on Earth. Many of the rocks seemed to have been formed in the presence of a strong magnetic field, which had astronomers scratching their heads. How could a small body like the Moon have generated a strong magnetic field?

New research might have an answer to this mystery. In a model published in Nature Astronomy, geoscientists show that strong magnetic fields could have been created when giant rock formations sunk down through the young Moon’s mantle, producing interior convection.

This might have happened up to 100 times in the first half-billion years of the Moon’s existence.

“Instead of thinking about how to power a strong magnetic field continuously over billions of years, maybe there’s a way to get a high-intensity field intermittently,” says Alexander Evans, co-author of the study from Brown University, US. “Our model shows how that can happen, and it’s consistent with what we know about the Moon’s interior.

“This model is able to explain both the intensity and the variability we see in the Apollo samples – something that no other model has been able to do.”

Polar bear on ice
Credit: Chase Dekker Wild-Life Images / Getty Images

Ocean temperature record smashed yet again

For the sixth year in a row, ocean temperatures have broken records – which means the world’s oceans are hotter than we’ve ever measured before.

A report published in Advances in Atmospheric Sciences summarises international datasets of ocean heat content since the 1950s.

“The ocean heat content is relentlessly increasing, globally, and this is a primary indicator of human-induced climate change,” says co-author Kevin Trenberth, from the National Center for Atmospheric Research in Colorado, US. “In this most recent report, we updated observations of the ocean through 2021, while also revisiting and reprocessing earlier data.”

The report found that the upper two kilometres of ocean absorbed 14 more Zettajoules in 2021 than in 2020. For reference, worldwide humans collectively use about half a Zettajoule of energy per year. Adding 14 Zettajoules per year is the equivalent of dropping seven Hiroshima bombs into the ocean per second for a year.

“As well as absorbing heat, currently, the ocean absorbs 20% to 30% of human carbon dioxide emissions, leading to ocean acidification; however, ocean warming reduces the efficiency of oceanic carbon uptake and leaves more carbon dioxide in the air,” says lead author Lijing Cheng, from the Institute of Atmospheric Physics at the Chinese Academy of Sciences.

“Monitoring and understanding the heat and carbon coupling in the future are important to track climate change mitigation goals.”

Stellar intruder caught red-handed

Astronomers have just spotted a rare stellar intruder – a star zooming through another, unrelated star system.

Bright streamer of material coming out from a star
This composite image includes data from the Subaru Telescope, Jansky Very Large Array, and the Atacama Large Millimeter/submillimeter Array, revealing in detail the perturbations, including long streams of material, made in Z CMa’s protoplanetary disk by the intruding object. Credit: ALMA (ESO/NAOJ/NRAO), S. Dagnello (NRAO/AUI/NSF), NAOJ

It paid a visit to the Z Canis Majoris (Z CMa) star system, which is a very young system made up of two protostars in orbit around each other. The intruder star zipped through, coming close to the infant pair and ripping through the gas and dust surrounding them.

Images – compiled by observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) – show the streamers of gas and dust formed by the fly-by.

“Observational evidence of flyby events is difficult to obtain because these events happen fast and it is difficult to capture them in action,” says Ruobing Dong, an astronomer at the University of Victoria in Canada.

“What we have done… is equivalent to capturing lightning striking a tree.

“This discovery shows that close encounters between young stars harbouring discs do happen in real life, and they are not just theoretical situations seen in computer simulations.”

The study was published in Nature Astronomy.

Twin triggers of Triassic extinction

201 million years ago, a mass extinction event wiped out about 75% of all marine life on the planet and paved the way for the rise of the dinosaurs.

Now, Australian-led research has pinpointed potential triggers of this end-Triassic extinction event: increased levels of acid and hydrogen sulfide in the oceans.

“The end-Triassic event saw rapid increases in CO2 due to a surge in volcanic activity, which is understood to have caused unfavourable conditions for life resulting in mass extinction – however, the multiple drivers for loss of life during this period were not previously known,” says Curtin University’s Calum Fox, who led the study in the journal Geology.

“By studying microscopic fossils preserved in rock in the Bristol Channel Basin, in the southwestern United Kingdom, we identified the twin mechanisms responsible for the mass extinction.

“These were a deadly combination of ocean acidification, which inhibited growth of all marine life using calcium carbonate to create shells or body parts such as mussels, oysters, and corals, and rising levels of hydrogen sulfide in the ocean, which was extremely toxic for all marine life.”

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