First humans out of Africa stopped at Persian Plateau on way to Eurasia

After Homo sapiens expanded out of Africa 70,000 years ago, they seem to have paused for some 20,000 years before colonising Europe and Asia. Now researchers think they know where. Looking at ancient and modern DNA, and the environment of the time, scientists have pinpointed the Persian Plateau — which in this definition encompasses Iran, the United Arab Emirates, Kuwait and parts of Oman — as the perfect place. Finding local archaeological evidence to confirm this could be difficult.

Wild Birds Gesture ‘After You’ to Insist Their Mate Go First

Japanese tits (Parus minor) flutter their wings to invite their mate to enter the nest first. Scientists who observed eight breeding pairs of wild tits noticed that when one of the birds sat in front of the next box and fluttered its wings, the other would go in first. It’s the first documented evidence of birds using a symbolic gesture: one that has a specific meaning (like waving ‘goodbye’) but isn’t simply pointing at an object of interest.

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Birds behaviourally demonstrate what they want another to do. This is also a way of teaching chicks. See Rainbow Lorikeet Semiosis

Weird electron behaviour thrills physicists

Two teams have observed that electrons, which usually have a charge of –1, can behave as if they had fractional charges (such as –⅔) — and do so without being nudged by an external magnetic field. It’s the first time this ‘fractional quantum anomalous Hall effect’ has been observed experimentally, and physicists are scratching their heads over exactly how it works. It’s a fundamental discovery that might also someday have practical applications: fractionally charged particles are a key requirement for a certain type of quantum computer.

Scientists discover that like-charged particles can sometimes attract

Everyone knows that usually, when it comes to charged particles, opposites attract. But in liquids, birds of a feather can flock together. Researchers investigating the long-standing mystery of why like-charged particles in solution can be drawn to each other have found that the nature of the solvent is key. The way that the liquid molecules arrange themselves around the particles can generate enough ‘electrosolvation force’ to overcome electromagnetic repulsion.

Planet-eating stars hint at hidden chaos in the Milky Way

Stellar detectives have identified seven stars that recently gobbled up a rocky planet. The planets seem to have been eaten during their stars’ relatively stable main-sequence period. If this is true, it means these systems have continued to be chaotic long after their formation, with planets disintegrating or falling into their star.

AI helps design antibodies from scratch

For the first time, an artificial intelligence (AI) system has helped researchers to design completely new antibodies. Creating new versions of these immune proteins, which can be used as drugs, is usually a lengthy and costly process. An AI algorithm similar to those of the image-generating tools Midjourney and DALL·E was trained on thousands of real-world structures of antibodies attached to their target proteins. It then churned out thousands of new antibodies that recognize certain bacterial, viral or cancer-related targets.

Hawking’s paradox still puzzles physicists

Physicist Stephen Hawking died six years ago, on 14 March 2018. Fifty years ago, he published a Nature paper with the enigmatic title: Black hole explosions? The paper introduced the concept of ‘Hawking radiation’: the idea that black holes are not truly black because they constantly emit a tiny amount of heat. As Hawking soon realised, this creates a paradox. Hawking radiation doesn’t maintain the details of the original material that went into the hole; therefore, it inexorably erases information from the Universe, contradicting the laws of quantum mechanics. Efforts to solve the conundrum have led to legendary wagers, a theory that wormholes connect the inside of black holes with the outside and the idea that the Universe is a hologram.

Indigenous Australian fire-stick farming began at least 11,000 years ago

Indigenous Australians have been using fire to shape the country’s northern ecosystems for thousands of years. Researchers analysed charcoal that was preserved in the sediment of a flooded sinkhole over the last 150,000 years. They discovered that, around 11,000 years ago, there was a shift to more frequent but less intense fires as a result of Indigenous fire-stick farming. European colonisation mostly brought an end to the practice, which might have contributed to the return of more high-intensity wildfires.

Bumblebees show behaviour previously thought to be unique to humans

Researchers who set up a confusing puzzle box with a sweet reward revealed that bumblebees (Bombus terrestris) can learn skills from others that they could not acquire alone — a behaviour thought to be unique to people. After showing that no lone bee could work out how to solve the puzzle, the scientists painstakingly trained nine bees how to do it. The trained bees became demonstrators for other bees, who watched, learnt and won their reward.

Oldest stone tools in Europe hint at ancient humans’ route there

Stone tools found in western Ukraine date to roughly 1.4 million years ago, making them the oldest known artefacts in Europe made by ancient humans. The findings support the theory that our early relatives — probably of the versatile species Homo erectus — first entered Europe from the east and spread west. The type of tools, and the location where they were found, hint that the first Europeans might have moved westwards along the valleys of the Danube River.

Amphibian nurses its young with ‘milk’

A species of amphibian is the first observed to nourish its young with a milk-like product, which it squirts from the cloaca, a combined rear opening for its reproductive and digestive systems. Siphonops annulatus is a blind, worm-like caecilian that lives underground. Lactation is considered a key characteristic of mammals, but a handful of other animals — including some birds, fish, insects and even spiders — produce nutrient-rich liquid for their offspring.

How heavy is a neutrino?

Physicists gathered this week to compare notes on how to weigh neutrinos, one of the most mysterious of the elementary particles. Currently, only one experiment in the world has a shot at making such a measurement — the massive, Zeppelin-shaped Karlsruhe Tritium Neutrino (KATRIN) detector in Germany. The researchers hope to build scaled-up versions of alternative experimental techniques that could eventually compete with KATRIN, or even improve on it.

How dwarf galaxies lit up the Universe after the Big Bang

Astronomers have used the James Webb Space Telescope to show that faint miniature galaxies swept away a fog of atomic hydrogen in the early Universe — allowing starlight to shine through the cosmos for the first time. Dwarf galaxies roughly 100 times smaller than the Milky Way triggered the process, known as reionisation.