Quantum mechanics and general relativity don’t fit together, and a big part of the issue comes down to gravity. For decades, the accepted route to an ultimate theory of everything has involved taking our best theory of gravity and squeezing it into the frame of quantum mechanics. Yet, almost a century later, scientists still haven’t managed to make gravity fit. Ivette Fuentes is a professor of quantum mechanics who conducts experiments at the scales where quantum theory and general relativity interplay. Fuentes sat down with New Scientist features editor Thomas Lewton to discuss the issues and fascinating theories that pop out when we try to fit classical and quantum mechanics together.

Read more: The experiments that could finally explain gravity

Homo sapiens have been around for about 300,000 years. Often, our big brains and intelligence are credited with making us the most successful species to have ever walked on Earth, but that isn’t entirely true. There was another species of human that survived on this very same planet for nearly 2 million years, which was the grandparent of so many other human species, including us. They explored new continents. They mastered tools. They may have controlled fire. And they did it all with a brain barely half the size of ours. Enter Homo erectus, a species that may force us to confront an uncomfortable possibility… that intelligence alone isn’t what makes a species successful.

Read more: How Homo naledi is changing what we know about death

Everything around us – from our bodies to the stars – is made of matter. But according to our best theories, none of it should exist. The big bang should have created equal amounts of matter and antimatter, and that should have caused the newborn universe to annihilate itself instantly. So why are we here?

In this video, we go behind the scenes at CERN, the world’s largest particle physics laboratory, to explore how scientists create, trap, transport and study antimatter at the appropriately named Antimatter Factory. Is there a tiny, fundamental difference between matter and antimatter? The answer could explain one of the oldest questions in science: Why is there something instead of nothing?

Read more: CERN upgrade: Inside the world’s largest scientific experiment

Physically, Homo sapiens isn’t that special in the animal world. But our species has discovered ways of beating the odds of survival in every habitat, from jungle to Arctic wasteland. In our latest interview with biological anthropologist and broadcaster Alice Roberts, we discuss the wonderful benefits bestowed on us by animals from our evolutionary past. The biochemistry in our cells goes back to the earliest single-celled creatures living in the ancient oceans, and our arms and legs date back to when the first amphibians crawled onto land around 360 million years ago.

Read more: These are the extinct humans that live on in your DNA

Antarctica is melting and one of its largest glaciers is collapsing from underneath. This is Thwaites glacier, sometimes called the doomsday glacier – and for good reason. If it destabilises, it could trigger a wider collapse of the West Antarctic ice sheet, raising sea levels by up to 5 metres. Scientists believe we may be approaching a tipping point that could completely redraw the world’s coastlines, putting cities such as Kolkata, New York and London at risk of severe flooding, displacing millions of people.

In our latest video, we speak directly to scientists involved in an international effort to better understand what is happening with Thwaites, what the risks involved are and why it’s potentially much more devastating than we previously thought.

Read more: The ‘doomsday’ glacier’s giant ice shelf is about to break away

On Q-Day, your privacy will be at stake. This is the moment when quantum computers break the encryption protecting the modern world, bank transactions become readable, private messages get exposed and even state secrets become vulnerable.

For years it sounded like sci-fi, something that was decades away from happening, if it happened at all. But now, research suggests that we may be hurtling towards Q-Day at a rapid speed.

In this video, New Scientist uncovers why many experts think the countdown to Q-Day may already have begun, and explains how quantum computers work and why these machines could both threaten the security of the modern world and unlock breakthroughs that could change our lives. Special thanks to Quantum Motion for letting us film at its facilities.

The New Scientist Book Club has been reading Luminous, Silvia Park’s near-future story set in a reunified Korea in which robots are fully integrated into society. Head of books Alison Flood caught up with Silvia to talk about how this increasingly dark story began as an idea for a children’s book, whether the advent of large language models affected their writing, and whether robots might one day achieve consciousness.

Read more: Why I explore our inevitable love for robots in my novel Luminous

Autism pioneer Uta Frith wants to dismantle the spectrum. After a career spent grappling with the condition’s neural underpinnings, she is unwavering in her controversial call to scrap our current view of it and start again. Frith’s influence on our ever-shifting understanding of autism has been monumental: she developed two landmark theories about how autistic minds might develop differently to neurotypical ones, and was among the first to test ideas like these using newly available brain scanners in the 1990s. Since then, the number of autism diagnoses has sharply risen, especially among women and girls – largely because of a softening and broadening of how we define the condition. But Frith thinks that many people at the milder end of the spectrum have little in common with those who are profoundly autistic. “There’s absolutely no overlap,” she says. “That is the sign that the spectrum isn’t holding.” In this video, she sits down with New Scientist editor Thomas Lewton to discuss autism.

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Homo sapiens aren’t as unique as we once thought. In fact, only about 1.5 to 7 per cent of our DNA originated in our species alone. Everything else we share with our ancestors and those human species we once coexisted with, including Neanderthals, Denisovans and even some yet-to-be-identified “ghost populations”. This rewrites the story we have told ourselves about our species. We just aren’t that unique.

When our ancestors met these other human species, they didn’t just compete with them: they mated with them. And those encounters left a permanent record in our DNA. In other words, those ancient humans we thought had vanished didn’t necessarily disappear… Some of them are still here inside you.

Read more: How Homo naledi is changing what we know about death

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