Wenlei Chen

Light from a distant galaxy travels toward us for billions of years, but along the way it can run into a massive galaxy cluster. Its gravity acts like curved glass: it bends the path of rays, so instead of one image, we see several — sometimes arcs, sometimes points.

The early Universe is often imagined as a nursery: most galaxies there are amorphous blobs, rowdy and irregular, choking on gas and bursts of star formation.