Y. Yao

At the heart of many galaxies lies an invisible beacon — a supermassive black hole. As it devours matter, it blasts a dazzling beam of gamma rays into space. If that beam points towards Earth, astronomers see a blazar — a bright but fickle point.

When a star wanders too close to a black hole, the black hole starts pulling it in. If the star doesn't fall in entirely but only loses some material, it can survive several such 'bites.' Each time, a chunk of gas is ripped off, heats up, and flares — astronomers see a bright spot in the sky.

A blast wave slams into a surface, and the surface starts to wrinkle like a carpet when you drag your foot across it. These wrinkles grow, curl into vortices, and stir everything around. In fusion, such mixing is a big problem: the fuel doesn't compress evenly, and the reaction fizzles out. Physicists have found a way to stop this process without touching the wave itself.

Earth is a closed book for those accustomed to leafing through pages with light. But to neutrinos, the invisible particles born in cosmic rays and barely remembering the prediction of Pauli, our planet is a braille script: each kilometer of depth presses its relief into their…

For almost a century, seismology has been the planet’s chief X-ray, probing the interior through elastic waves. But neutrinos, ghost particles predicted by Wolfgang Pauli, offer a different perspective.

Deep beneath the ice of the South Pole, nearly two and a half kilometers down, an unusual telescope is at work. It is not pointed at the sky but through the Earth. Its quarry: neutrinos, nearly elusive particles that pass through planets and stars without interacting with anything.