If you look across space with a telescope, you'll see countless galaxies, most of which host large central black holes, billions of stars and their attendant planets. The universe teems with huge, spectacular objects, and it might seem like these massive objects should hold most of the universe's matter. But the Big Bang theory predicts that about 5% of the universe's contents should be atoms made of protons, neutrons and electrons. Most of those atoms cannot be found in stars and galaxies ' a discrepancy that has puzzled astronomers. If not in visible stars and galaxies, the most likely hiding place for the matter is in the dark space between galaxies. While space is often referred to as a vacuum, it isn't completely empty. Individual particles and atoms are dispersed throughout the space between stars and galaxies, forming a dark, filamentary network called the 'cosmic web.' The census comes to several hundred billion galaxies, each made of several hundred billion stars. The numbers are uncertain because many stars lurk outside of galaxies. That's an estimated 1023 stars in the universe, or hundreds of times more than the number of sand grains on all of Earth's beaches. There are an estimated 1082 atoms in the universe....

Black holes can get energy boosts by 'snacking', although their dish of choice is rather different from our own. Analysis suggests that the most luminous burst of light ever detected from a black hole ' a fireworks show that was, at its peak, more than 10 trillion times brighter than the Sun ' flared up as the black hole gobbled up a star that was at least 30 times as massive as the Sun. When astronomers first laid eyes on the object in 2018, they didn't realize it was a superflare. After noticing the object brighten, researchers zeroed in on it with the Palomar Observatory's 200-inch Hale Telescope. But a graph of the light emitted by the object proved disappointing. 'It didn't seem nearly as interesting as we thought it was,' says Matthew Graham, an astronomer at the California Institute of Technology in Pasadena and a co-author of the paper. However, in 2023, the team noticed that, even after five years, the black hole remained peculiarly bright. So they took a closer look using the W. M. Keck Observatory in Hawaii, which revealed that the object was roughly 3 million kiloparsecs, or 10 billion light years, away. To appear so bright at such a great distance, the jets of light must have been particularly luminous. Astronomers now say that the flare is 30 times more luminous than any previously detected blaze of light from a black hole....

When the James Webb Space Telescope (JWST) looked back in time to observe the Universe's earliest moments, it presented astronomers with something most peculiar: hundreds of 'little red dots' that inexplicably freckled the ancient cosmos. The specks, named for their compact size in JWST images and their emission of long, 'red' wavelengths of light, initially baffled astronomers. They seemed too condensed to be galaxies, yet didn't emit the right kind of light to be black holes. Researchers quickly dubbed the dots, which JWST first detected in 2022, Universe breakers, because they contradicted standard thinking about the features of the early Universe. Over the past few months, researchers have begun to settle on the identity of these dots, and it's one that seldom emerges in astronomy: a brand-new type of celestial object. 'It's extremely rare that you get to work on a truly new physical phenomenon like this,' says Anna de Graaff, an astronomer at the Max Planck Institute for Astronomy in Heidelberg, Germany. 'It's almost a shame that we're starting to figure them out.'...

To study the origins of our universe is to struggle with profound chicken-or-egg questions. We know the Big Bang happened. Cosmologists can see its afterglow in the sky. But no one knows whether the laws of physics or even time itself existed before that moment. Nor can we say exactly what happened next. The order in which certain celestial objects formed during the very early universe is hotly contested. For a long time after the Big Bang, not much of anything could form. All of space was permeated by a roiling plasma. It was too hot and chaotic for any structure to cohere. Hundreds of thousands of years passed before a tiny hydrogen atom could even hold itself together. Another 100 million years or so after that, great clouds of hydrogen condensed and stars flared into being. Most cosmologists believe that these stars were the first large, free-floating structures to illuminate our universe, and that black holes appeared later. But some have proposed that it went the other way around....