Cosmology

For decades, astronomers treated the interstellar medium as a static backdrop to the goings-on of the universe. Now, a wave of 3D mapping is bringing the interstellar medium’s dynamic nature into focus.

Astrophysicist Shep Doeleman explains how capturing the first image of a black hole required a telescope the size of the world, and why the next goal is to create a movie.

The James Webb Space Telescope spots mysterious “little red dots” everywhere. A bold new theory suggests they’re suns dozens of times larger than our entire solar system.

One of the most contested issues in astrophysics is our understanding of the Universe’s expansion. Adam Riess discusses why there is disagreement and what might resolve it.

Faced with observations of early black holes and galaxies that weren’t expected to exist, scientists have come up with a wealth of new theories to explain them. Now they just need to figure out which ones are true.

Recent observations suggest that dark energy is changing over time. Theorists wonder if dark matter is, too.

Astronomers are preparing for a new era of big-data astronomy, and results are already starting to arrive.

Today’s observatories document every pulse and flash in the sky each night. To understand how the cosmos has changed over longer periods, scientists rely on a more tactile technology.

Physicists spotted a “terribly exciting” new black hole, doubled down on weakening dark energy, and debated the meaning of quantum mechanics.