Science

Some 1,000 years ago, a small band of Polynesians sailed thousands of miles across the Pacific to settle one of the world’s most isolated places—a small, previously uninhabited island they named Rapa Nui. There, they erected hundreds of “moai,” or gigantic stone statues that now famously stand as emblems of a vanished civilization. Eventually, their numbers ballooned to unsustainable levels; they chopped down all the trees, killed off the seabirds, exhausted the soils and in the end, ruined their environment. Their population and civilization collapsed, with just a few thousand people remaining when Europeans found the island in 1722 and called it Easter Island. At least that is the longtime story, told in academic studies and popular books like Jared Diamond’s 2005 “Collapse.” A new s...

Adobe Stock/Erika Eros/Alamy/Collage: Ryan Wills Deep inside a black hole, the cosmos gets twisted beyond comprehension. Here, at some infinitesimal point of infinite density, the fabric of the universe gets so ludicrously warped that Albert Einstein’s general theory of relativity, which describes how mass bends space-time, ceases to make sense. At the singularity, our understanding falls apart. As daunting as singularities are, each one is at least safely tucked away inside the event horizon of a black hole, the boundary beyond which we can’t see. This not only cloaks them from view, but also stops unknown effects they herald, namely the horrors of unpredictability, from leaching out into the wider universe. But what if singularities could exist outside black holes af...

The sand dike exposure and research team in the Ganges floodplain of Bangladesh. Photo: Liz Chamberlain Liz Chamberlain and Steve Goodbred, two sedimentologists from Vanderbilt University, were traipsing around coastal Bangladesh in March 2018 when they saw the sand dikes. Chamberlain and Goodbred had come to Bangladesh to investigate how fast rivers meander, or shift, in the coastal part of the Ganges-Brahmaputra Delta. Their research team, also consisting of Goodbred’s graduate student Rachel Bain, and Abdullah Al Nahian and Mahfuzur Rahman from Dhaka University, was taking sediment samples from loops in the many rivers that cross the lower delta plain. They would use these samples to date the sediments left behind as the rivers shifted. Midway through the trip, they came acros...

An analysis of millions of tweets reveals the changing meaning of the word “bot”Svet foto/Shutterstock Calling someone a bot on social media once meant you suspected they were actually a piece of software, but now the use of the word is shifting to become an insult to someone you know is human, say researchers. Many efforts to detect social media bots use algorithms to try to identify patterns of behaviour that are more common in automated accounts controlled by computers, the traditional meaning of a bot, but their accuracy is questionable. “Most recent research really focuses on the detection of social bots, which is problematic in itself because we have this ground truth problem,” says Dennis Assenmacher at Leibniz Institute for Social Sciences in Cologne, Germany, ...

Hitting certain crystals with lasers makes them produce quantum lightJaka Korenjak Creating quantum light just became easier thanks to liquid crystals like the ones found in television screens. Light with quantum properties is crucial for many future technologies. Entangled particles within such light could help produce quantum communications networks to support an unhackable internet or quantum imaging techniques for biomedicine. Matjaž Humar at Jožef Stefan Institute in Slovenia says that despite these advanced applications, the methods for making quantum light have barely changed for six decades – until now. He and his colleagues devised a way to create it with liquid crystals. Team member Vitaliy Sultanov at the Max Planck Institute in Germany says traditional...