Guodong Li

Quasar W2246–0526 is a beacon lit when the universe was just 1.3 billion years old. Its light has traveled 12.8 billion years to reach us, yet even at such a distance, astronomers have spotted what had eluded them for decades: the gravitational shadow of a black hole.

Climate scientists have long debated where exactly the El Niño "pool" is located: the region in the equatorial Pacific that first responds to an impending weather shift. The debate isn't due to a lack of data. The ocean is measured along longitude, latitude, and depth, and each slice contains thousands of numbers. The problem is that there are too many numbers to see the pattern directly.

Two houses with identical facades but different interior layouts: from the outside the V-shaped spectrum looks the same, but inside there are different light sources and different amounts of dust. That is exactly how the two populations of distant galaxies that astronomers have long confused appear.

A quasar is a supermassive black hole at the center of a galaxy that devours matter and shines brighter than all the stars around it. Some of that energy goes into radio emission, which, it was thought, could heat or expel cold gas — the raw material for new stars.