The 2026 science Nobels: a light switch for the brain, ghost particles and mirror molecules

Medicine: a molecular switch for nerve cells

The Nobel Prize in Physiology or Medicine, announced on 5 October, went to Karl Deisseroth, a 54-year-old professor at Stanford University in the US, and to two German scientists: Peter Hegemann, 71, of Humboldt University of Berlin, and Georg Nagel, 73, of the University of Würzburg. The Nobel Assembly honoured them for their discovery of a molecular switch for nerve cells.

The work began in the early 1990s, when Hegemann wondered how a single-celled green alga called Chlamydomonas could swim towards light. With Nagel, he identified channelrhodopsin, a light-sensitive channel in the cell membrane. Deisseroth then put the gene for this protein into rat nerve cells, and a landmark 2005 paper from his laboratory helped launch the field known as optogenetics: controlling nerve signals with light.

Optogenetics helps researchers work out which cells are responsible for which functions, including learning, fear, addiction and movement. It is being studied as a treatment for disease, and researchers hope it could make cochlear implants more precise.

Physics: catching ghost particles in Antarctic ice

The physics prize, announced on 6 October, went to Francis Halzen, a Belgium-born physicist at the University of Wisconsin–Madison and the principal investigator of the IceCube Neutrino Observatory. He was honoured for decisive contributions to IceCube and the discovery of high-energy neutrinos of astrophysical origin.

Neutrinos are the least understood of the 17 fundamental particles known to exist. They pass through ordinary matter almost unnoticed, so catching them needs an enormous detector. IceCube's sensors are spread through a cubic kilometre of clear ice, about a mile beneath the surface of Antarctica, and it remains the largest neutrino telescope in the world.

IceCube came online in 2010 and, after a couple of years, confirmed that it had measured the first high-energy neutrinos from beyond the solar system. Combining neutrino data with ordinary telescopes and gravitational-wave detectors has since improved scientists' understanding of distant, violent events in the universe.

Chemistry: why molecules have a preferred hand

The chemistry prize, announced on 7 October, went to Henri Kagan of Paris-Sud University and Kenso Soai of the Tokyo University of Science, for discovering non-linear effects and autocatalysis in asymmetric organic synthesis.

Many molecules are chiral: like a left and a right hand, they are mirror images that cannot be superimposed on each other. Kagan showed that using particular catalysts can produce more of one hand than the other. Soai went further, using chiral molecules as their own catalysts to make more of themselves.

The work has been integral to the pharmaceutical industry and to developing new molecules, Scientific American reported, and it could help explain how life first arose on Earth, where living things use mostly one hand of many molecules.

The prizes

Each prize is worth 12 million Swedish kronor, about $1.2 million, shared between the winners. The medicine, physics and chemistry prizes are presented in Stockholm on 10 December.