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

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