Yosuke Mizuno

In 2019, astronomers unveiled the first-ever image of a black hole's shadow — a dark void encircled by a lopsided orange ring. This is the supermassive black hole at the heart of galaxy M87, 55 million light-years away. The ring isn't just glowing: one side is noticeably brighter than the other, like a campfire burning unevenly, with flames leaping higher on one side.

The farther apart the antennas, the finer the details they pick up. By merging signals, astronomers effectively turn multiple dishes into a single telescope as big as the distance between them. Add a lunar antenna to the Earth-based array, and you get a virtual eye 384 000 km wide.

Radio telescopes scattered across the globe pick up waves from distant black holes. But two telescopes placed almost side by side see only a blurry blob — fine details are beyond them. Usually, such pairs are considered useless and discarded. But that's a mistake: even a blurry blob holds clues.

A white dwarf is what remains of a star like the Sun after it sheds its outer layers. What's left is a hot core the size of Earth but with a mass close to that of the Sun. A teaspoon of this material would weigh as much as a truck. Some of these stars have extremely strong magnetic fields — a billion times stronger than Earth's.

At the center of the Milky Way lies the supermassive black hole Sagittarius A*. It is four million times more massive than the Sun, but by cosmic standards it behaves quietly: it only occasionally flares up when it swallows a clump of gas.

The shadows of supermassive objects at the centers of galaxies, M87 and the Milky Way, have become icons of modern astrophysics. But what if these shadows are not from absorption, but passage? The equations of Einstein allow for traversable wormholes — tunnels in the fabric of spacetime.

In April 2021, the antennas of the Event Horizon Telescope (EHT)—a global network of millimeter-wave radio telescopes — zeroed in on a tiny spot in the constellation Virgo.