Nan Li

A galaxy cluster's gravity warps spacetime, acting like a colossal lens: it focuses and amplifies light from distant objects, as predicted by Einstein. Such lenses are rare, but they let us glimpse what lurks at the edges of the cosmos.

Inside the receiver of a telescope aimed at the oldest glow in the universe sits a tiny thermometer chip. It's so sensitive that the heat from a single photon can warm it noticeably. But to hear that whisper of heat, you need a middleman — an amplifier that doesn't add its own noise.

Light in a microscope doesn't arrive as a steady stream but like buckshot from a bag: sometimes more photons, sometimes fewer. This random scatter is the shot noise. It sets a limit: faint signals from tiny objects get lost in the ripple. Scientists have found a way to calm this buckshot.

In a cold cloud of atoms chilled to near absolute zero, energies can behave like threads that weave into braids. These braids are not just a pretty image: their pattern is tied to topology, the branch of mathematics that studies properties preserved under continuous deformations.

A sugar cube weighs about a gram. But a black hole that could hide inside such a cube would weigh as much as a small mountain — billions of tons. Yet even such tiny things, born in the first instants after the Big Bang, should have vanished long ago.

A huge pool of clear liquid is hidden deep underground. Inside, there is nothing but a pristine 'broth' that flashes with faint light when an invisible particle flies through. This is the JUNO detector—20,000 tons of liquid scintillator built to hunt for neutrinos. The main enemy of such a hunt is not darkness but its own noise.