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Fish camouflage better without friends watching

Like chameleons of the sea, gobies change colour to hide from predators like larger fish and birds – and they do so better when they’re alone.

A new study published in Royal Society Open Science tested the colour-changing ability of these bottom-dwelling fish alone and in pairs. When by themselves, the fish were able to match a black-and-white background much more closely and quickly.

Three small brown fish on black and white background
A goby changing colour. Credit: Encel/University of Sydney

The researchers suggest this is because the fish feel calmer and more secure in numbers, and so feel less need to use up energy to hide.

“Grouping behaviour can reduce stress in fish, partly because they are in less danger of attack by predators,” says lead researcher Stella Encel from the University of Sydney. “This ‘safety in numbers’ effect may allow them to change colour more slowly without added risk.

“Since stress hormones like cortisol and adrenaline are central to the neurological mechanisms of colour change in fish, it’s possible that stress levels also directly affect their ability to camouflage.”

Captain Kirk finally makes it to space

Star Trek actor William Shatner successfully blasted off into space last week on Blue Origin’s New Shepard rocket.

For four decades, Shatner played the role of Captain James Kirk, commander of the USS Enterprise, and now he has finally spent an “unbelievable” 11 minutes in space.

“I hope I never recover from this,” Shatner said following his touchdown.

“I’m so filled with emotion about what just happened. It’s extraordinary, extraordinary. It’s so much larger than me and life. It hasn’t got anything to do with the little green men and the blue orb. It has to do with the enormity and the quickness and the suddenness of life and death.

“To see the blue colour whip by you, and now you’re staring into blackness … everybody in the world needs to do this. Everybody in the world needs to see this.”

The 90-year-old Canadian also became the oldest human in space.

The flight, launched from the Texan desert, was Blue Origins’ second crewed mission.

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Jeff Bezos greets William Shatner and other crew members of Blue Origin’s New Shepard after the crew capsule landed back in Texas, the United States. Credit: Blue Origin/Anadolu Agency/Getty Images

Dead star is a glimpse at our Solar System’s future

For the first time, astronomers led by the University of Tasmania have found a Jupiter-sized planet orbiting a white dwarf star in our galaxy – and it might be a hint of how our own Solar System will end.

Depending on their mass, stars follow different evolutionary routes when they run out of fuel to burn and “die”, becoming white dwarfs, neutron stars or black holes. A small star like our Sun will eventually violently shed its outer layers and become a white dwarf: a dense ball of carbon and oxygen, slowly cooling and dimming as time passes.

Artist impression of white dwarf system surrounded by a debris ring
Credit: W. M. Keck Observatory/Adam Makarenko.

In a paper published in Nature, astronomers have reported the discovery of a gas giant orbiting fairly close to one of these stellar corpses, just 2.8 times further away than the Earth to the Sun.

The finding suggests that planets of this size and orbital distance can survive the death of their host stars (although other, closer planets might be burnt to a crisp).

The researchers say that it also supports the prediction that more than half of white dwarfs have Jupiter-like planets whizzing around them.

The next question is – how do we spot them? And is there life there?

Shell-shocking new species

The curator of the Queensland Museum has discovered a new species of mollusc among a massive donated collection of shells.

About a hundred shells laying on a sheet of paper
Thora Whitehead Shell Collection, volute snails. Credit: Dr John Healy – Queensland Museum

The collection, which contains more than 200,000 specimens, belonged to Brisbane resident Mrs Thora Whitehead.

“Much of the material was collected by Thora over 50 years from localities around the Australian and especially Queensland coastlines, from habitats as diverse as mangroves, surf beaches, shell beds, rock platforms and coral reefs,” says John Healy, the Queensland Museum Curator Marine Environments (Molluscs).

The new species of carnivorous marine snail is called Amoria thorae and is so rare that scientists haven’t yet seen a live specimen – it’s known only from empty shells trawled off the coast of NSW and Queensland in the 1970s.

“You can imagine my delight when photographing this new collection, I found not one, but two specimens of this potentially new species,” says Healy said.

“My hope is that one day the living animal will be found, photographed and studied so we may better understand its biology and relationships.”

Mixing sunscreen might let in harmful rays

Summer is on the way and Australians will soon be slip, slop, slapping to protect their skin from the Sun. But be careful when choosing sunscreen – because new research has found that mixing different types could weaken sun protection.

Close up of mom's hands applying lotion on boys face
Credit: Cavan Images / Getty Images

The study, published in the journal Photochemical & Photobiological Sciences, discovered that chemical (non-mineral) sunscreen became much less effective at blocking UVA rays when it was combined with a common ingredient, zinc oxide.

In their experiment, the team tested different types of sunscreen under two hours of a simulated “Sun”. They found that the sunscreen mixed with zinc oxide had a reduced UVA protection factor of up to 91.8%, compared to 15.8% for the same sunscreen without zinc oxide.

Richard Blackburn from the University of Oregon, co-author of the study, says: “We still recommend consumers use sunscreen but suggest they should be careful to avoid mixing sunscreen with zinc oxide, whether intentionally with hybrid sunscreens that combine small-molecule UV filters with zinc oxide, or incidentally by mixing sunscreen with other products containing zinc oxide, such as makeup containing SPF.”

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