Optics

Light can be reflected not only in space but also in time—and researchers exploring such “time reflections” are finding a wealth of delightfully odd and useful effects

Money, engineering and sheer geometry may mark an end of the line for building ever larger astronomical telescopes

Fresh images show off the Euclid space telescope’s ability to capture crisp pictures of vast swaths of sky

The James Webb Space Telescope is gazing across the universe to find galaxies close to the “cosmic dawn”—and you can explore them from the palm of your hand

The darkness of the night sky offers a profound insight on the nature of the cosmos

A surprisingly complex galaxy cluster suggests that in the search for dark matter, nothing is as simple as it seems

A colorful quirk of quantum optics could lead to significant advances in quantum communication and computing

This annular solar eclipse will only reveal its full glory to a select few, but onlookers across much of the Western Hemisphere can catch a partial glimpse of the dazzling phenomenon

Black holes in the extraordinarily distant cosmos are out of tune with their host galaxies, offering insights into their formation

A new view of a record-shattering distant star shows it to be twice as hot as our sun and likely accompanied by a stellar companion

The European Space Agency's ambitious Euclid space telescope is on its way to decoding the secrets of dark matter and dark energy

The “magnitude scale” for measuring stellar brightness also reveals the limits of naked-eye stargazing