Chihway Chang

When light from a distant galaxy travels toward us, dark matter along the way bends the rays slightly, like imperfect glass. Astronomers measure these distortions to understand where the invisible mass lurks. But galaxies also have their own, "intrinsic" distortions: they align not randomly but along the invisible threads of the cosmic web.

Astronomers have tested the new Vera C. Rubin telescope in Chile, much like adjusting the focus and aperture on a brand-new camera. The first images covered a patch of sky the size of 60 full Moons, and immediately revealed millions of galaxies and stars. The imaging was done in various colors, from invisible ultraviolet to thermal infrared.

Light from distant galaxies travels to us for billions of years, but along the way it gets bent and twisted by the invisible web of dark matter. This effect, predicted by Albert Einstein within general relativity, is called gravitational lensing.