Science news in brief: From underwater Christmas tree worms to how we can hear silent GIFs

A round-up of science stories from around the world

The best festive firs don't grow in soil and they're not even plants (Creative commons)

To see the best Christmas trees, you’ll need scuba gear

Your Christmas tree is nice — really, it is. It’s just the right height and shape, it's so green and it smells so good. You definitely picked the best one in all of the land.

But that’s where you messed up.

The most beautiful Christmas trees don’t grow in soil. They’re not even plants.

Allow me to introduce a sea creature that will put your Christmas tree to shame: It’s name is Spirobranchus giganteus, but most people call it the Christmas tree worm.

These animals live on coral reefs in tropical and subtropical waters around the world, building tiny, tubular homes with their own secretions of calcium carbonate. They emerge from these tubes to filter feed, procreate and breathe with a part of their body called the branchial crown.

You can’t miss these bright, spiral-shaped cones while snorkelling, if you know what to look for. They look like miniature decorated firs.

“They’re really pretty, very colourful, very festive and Christmassy,” says Orly Perry, a marine biologist studying them as a doctoral student at Bar-Ilan University in Israel.

Most of the “trees”, which come in pairs, protrude no more than an inch from the tube’s opening. But they make up for their small size with colourful displays that look like the work of a talented candy maker. Many spiral out in a mixture of purples, greens and whites where Perry works on the Gulf of Aqaba, in the Red Sea. But they come in many other colours, too, and some even don an appropriate winter white.

Researchers have found that Christmas tree worms may protect some corals from bleaching, algal smothering and predation from animals like the crown-of-thorns starfish.

Once stuck, Christmas tree worms can’t run, but they can hide. Sensing touch, chemicals and light, they can perceive danger. When it approaches, the worms retract, vanish into their homes and slam shut an organ called an operculum — just like a door.

But the worms spend most of their time out of their tubes feeding, all year, day or night: Which means for corals, it’s Christmas all the time.

The Great Red Spot descends deep into Jupiter

'We just know enough to know we were wrong' (Nasa) (NASA)

Jupiter’s Great Red Spot is not just a skin-deep beauty mark. Instead, the iconic storm descends at least 200 miles beneath the clouds and possibly much deeper.

That is one of the latest findings of Nasa’s Juno spacecraft, which passed directly over the storm in July.

Juno is designed to peer beneath the clouds of Jupiter, our solar system’s largest planet, and its observations have upended scientists’ notions of how a big ball of hydrogen ought to behave. They have not yet come up with a new understanding of Jupiter.

“We just know enough to know we were wrong,” says Scott Bolton, a scientist at the South-west Research Institute in San Antonio, Texas, who is the mission’s principal investigator.

The Juno scientists presented their latest findings last week at a meeting of the American Geophysical Union in New Orleans.

Before Juno, astronomers could only observe the swirling of the cloud tops in the Great Red Spot, which is 10,000 miles wide — large enough to swallow Earth. Last year, scientists using an infrared telescope in Hawaii reported that the atmosphere 350 to 600 miles above the spot was exceptionally hot, averaging 2,500°F (1,371°C).

But no one knew what was happening below the clouds.

An instrument on Juno measures microwave emissions, which pass through the clouds into space. Warmer regions generate more microwaves, and the region below the Great Red Spot was warmer, even 200 miles down, the deepest that the microwave instrument could peer. The deep heat likely explains the source of the energy driving the storm.

Andrew P Ingersoll, a professor of planetary science at the California Institute of Technology and a member of the Juno team, noted that the roots of the Great Red Spot go down 50 to 100 times deeper than the Earth’s oceans.

“It’s definitely warmer than its surroundings at that great depth,” Ingersoll says. “How deep it goes beyond that is still TBD.”

Ticks trapped in amber sucked dinosaur blood

It's unusual to find a parasite with its host in a fossil

Palaeontologists have found entombed in amber a 99-million-year-old tick grasping the feather of a dinosaur, providing the first direct evidence that the tiny pests drank dinosaur blood.

Immortalised in the golden gemstone, the bloodsucker’s last supper is remarkable because it is rare to find parasites with their hosts in the fossil record. The finding, which was published 12 December, gives researchers tantalising insight into the prehistoric diet of one of today’s most prevalent pests.

“This study provides the most compelling evidence to date for ticks feeding on feathered animals in the Cretaceous,” says Ryan C McKellar, a palaeontologist at the Royal Saskatchewan Museum in Canada, who was not involved in the study.

David Grimaldi, an entomologist at the American Museum of Natural History and an author of the paper published in the journal Nature Communications, was inspecting a private collection of amber from northern Myanmar when he and his colleagues spotted the eight-legged stowaway.

Upon further inspection, he and his colleagues concluded that the tick was a nymph, similar in size to a deer tick nymph, and that its host was most likely some sort of fledgling dinosaur no bigger than a hummingbird, which Grimaldi referrs to as a “nanoraptor”. The parasites were most likely unwanted roommates living in the dinosaurs’ nests and sucking their blood.

“These nanoraptors were living in trees and fell into these great big blobs of oozing resin and were snagged,” he says.

Trapped, too, were the ticks.

“We’re looking at a microcosm here of life in the trees 100 million years ago in northern Myanmar,” Grimaldi says.

They determined that the host was a non-avian dinosaur and not a modern bird based on molecular dating, which suggested the specimen was at least 25 million years older than modern birds.

Why we “hear” some silent GIFs

Can you hear the pylons thud?

This month, in an improbable turn of events, the sound of silence went viral.

An animated GIF showing an electrical tower jumping over delightfully bendy power lines began to spread. The frenzy started when Lisa Debruine, a researcher at the Institute of Neuroscience and Psychology at the University of Glasgow, asked Twitter users in an unscientific survey whether they could hear the image — which actually lacks sound, like most animated GIFs. Nearly 70 per cent who responded said they could.

But can you actually hear something that does not emit a sound?

Certainly, says Chris Plack, a professor of audiology at the Manchester Centre for Audiology and Deafness, who researches acoustic reflexes and auditory processing.

“Hearing,” as he defines it, does not require external noise; rather, it is “having the experience of a sound”.

Over the past few years, Elliot Freeman and Chris Fassnidge, cognitive neuroscience researchers at the University of London, have been studying what they call “visual-evoked auditory response”, or vEAR.

The ability to “vEAR” is not limited to scenes where one would expect to hear a noise, they say. One lab study found that more than 20 per cent of people could hear flashing lights in silent videos. A range of motions, abstract patterns and even colours evoke sound for some.

Rob Desalle, an evolutionary geneticist and curator of the Our Senses exhibit at the American Museum of Natural History, calls it a “clever illusion caused by filling in”.

“Our brains see this and they say, ‘Wow, a pylon of that size bouncing up and down should be making a noise’,” he says. So we hear one.

Fassnidge agrees that there is something about the pylons GIF that makes it particularly easy to imagine what it might sound like. Visual hearing is often about some “intersection of perception, memory and imagination all coming together”, he says.

But why do some people have much more advanced vEARing than others?

Freeman’s and Fassnidge’s working theory is that the degree to which one can hear based on visuals likely has to do with how much a given person’s “visual and auditory areas ‘talk’ to each other” in the brain.

How layers in a latte form

The #layeredlatte was created by accident (Shutterstock) (Shutterstock / Oliveshadow)

Any good barista will tell you that if you want to make a nice latte you pour milk into the espresso — not the other way around.

But there’s another style of latte out there, too — the layered latte, or #layeredlatte as you’ll find on Instagram. Created by accident, or by baristas experimenting with new drinks, these striped beverages start with a glass of heated milk and then pour in the espresso.

Bob Fankhauser, a retired engineer in Portland, Oregon, accidentally created his own layered latte at home and wanted to know why these pretty layers form.

Last year, Fankhauser sent an email including photos of his accidental layered lattes to Howard Stone, a chemical engineer who studies fluid dynamics at Princeton University, and inspired him and a graduate student to test this out. The team published their results 12 December in Nature Communications.

After recreating the latte with their own espresso and milk, the team created a simulated coffee drink, injecting heated, dyed freshwater into heated, denser saltwater to test the scientific parameters that make this spontaneous layering possible. Pouring hot espresso into warm milk at a certain speed, they found, induced an interaction between temperature and density that caused the drink to separate into layers of different densities.

The same basic phenomenon, called double-diffusive convection, creates layers of water in the ocean.

Nan Xue, a graduate student in Stone’s lab who led the study, found that even if you disturb the layers with a gentle stir, they will reform and stay put — for minutes, hours, even days.

As long as the mixture is still warmer than the air around it, the stirring creates another density gradient, similar to that produced by pouring. But stir after the latte reaches room temperature — bye-bye stripes.

To create your own layered latte, pour hot espresso over a spoon into a tall glass of milk of about the same temperature. Wait a few minutes for the layers to form as the liquid cools.

Moon may orbit the tiny distant object Nasa will soon visit

MU69 can only be seen from the Hubble telescope

In just over a year, a Nasa spacecraft will visit a tiny world at the edge of the solar system. Now that tiny object appears to have an even tinier moon, scientists announced 12 December.

The object, known as 2014 MU69, is small, no more than 20 miles wide, but planetary scientists hope that it will turn out to be an ancient and pristine fragment from the earliest days of the solar system.

The moon, if it exists, might be about 3 miles wide, circling at a distance of about 120 miles from MU69, completing an orbit every two to four weeks, estimates Marc W Buie, an astronomer at the South-west Research Institute in Boulder, Colorado.

He cautioned that the findings were tentative. “The story could change next week,” he says.

Buie and others working on Nasa‘s New Horizons mission provided an update last week at a meeting of the American Geophysical Union.

New Horizons flew past Pluto two years ago, sending back spectacular views that revealed a world with soaring mountains of ice, smooth plains and maybe even a subsurface ocean of liquid water.

New Horizon’s work is not yet done. Pluto is the largest object in the Kuiper belt, a ring of icy debris beyond Neptune. After the Pluto flyby, mission managers shifted the spacecraft’s trajectory towards MU69, located one billion miles beyond Pluto.

New Horizons will zip past MU69 on 1 January 2019.

MU69 is so small that it can be seen only by the Hubble Space Telescope and then only as a faint point of light.

© New York Times