Has all this happened before, and will all this happen once again? There are only a few questions, when we ask them, that force us to reckon with the fundamental nature […]

Even addition has to play by different rules for black holes. How do you add 28 and 47 together? This simple math question helps us highlight the many different ways that […]

We have to use the right definition for the specific question we’re asking. When it comes to the Universe, we frequently characterize objects by examining and reporting on their physical […]

And which ones are probably examples where we’ve fooled ourselves? Every once in a while — multiple times per year — a new research finding fails to line up with our theoretical expectations. In […]

And, at some point, did the Milky Way lose ours? There are some 400 billion objects flying through the Milky Way galaxy with enough mass that — if they were all made of […]

At just 3 solar masses, it eliminates the “mass gap.” Searching for black holes is one of the most difficult astronomical games a scientist can play. Emitting no light of their […]

Mass determines a star’s fate… except when it doesn’t. Supernova events are common, visually spectacular astronomical cataclysms. In 1987, a supernova just ~168,000 light-years away was observed in the Large Magellanic […]

The densest objects that haven’t collapsed to black holes can tell us information about the Universe unlike anything else. Swarming through our own galaxy, we’ve detected quite a few bizarre objects: […]

Enough mass in one location will always create a black hole. But not all masses are possible. If you take enough mass and compress it into a small enough volume […]

When you measure not just light, but light’s polarization, you learn so much more. It’s been over 100 years since the first solution for a black hole was discovered in General […]

It’s one of Einstein’s most bizarre predictions. And it’s true. There’s no such thing as absolute time. No matter where you are, how fast you’re moving, or how strong the gravitational […]

The most massive nearby stars could be the seeds our supermassive black holes need. The problem with the Universe, as we see it today, is that we only get a snapshot […]

Even before the Big Bang, energetic radiation was always present. When it comes to the physical Universe, the notion of “nothing” may truly be possible only in theory, not in […]

By the end of the decade, we may discover one million black holes. A large enough mass in a compact volume inevitably forms a black hole. Both inside and outside the […]

The inevitable long, slow decline is accelerating, and there’s nothing we can do. The Universe, as it is today, is less active, is forming fewer stars, and is creating fewer chances […]

Just say no to artist’s illustrations. This is what the Universe actually looks like. The Universe we observe often surpasses our greatest imaginings. This 20-year time-lapse of stars near the center […]

Avi Loeb says it’s aliens. Every other astronomer disagrees. Here’s why. In 2017, an astronomical event occurred that was unlike any other: for the first time, we observed an object that […]

Time always moves in the same direction, but what if the Universe were contracting? As we step forward in time, a number of things always seem to happen together. Objects […]

The newest record-setting quasar houses an enormous black hole. No one knows how. In every scientific field, we’re always on the lookout for whatever new discovery might reveal what’s currently beyond […]

For the cosmos, it’s all too easy being green. Stars come in a wide variety of colors, but never green. Stars form in a wide variety of sizes, colors and masses, […]

Two stellar mass black holes, if they merge in the vicinity of a supermassive black hole, could have their gravitational wave signal affected by the strongly curved space around them. […]

It doesn’t propagate at infinite speeds, and that’s a problem for Newton. When you look at the Sun, the light you’re seeing isn’t the light that’s being emitted right now. Instead, […]

There’s more light than we can account for, and we’ve just measured it robustly for the first time. When we look out at the darkest night skies available on Earth, even […]

They’re not just a theoretical prediction of quantum gravity. They should be detectable, too. The Universe, if you look at it closely and carefully enough, is fundamentally quantum in nature. […]

Entropy always increases, but that doesn’t mean it was zero to start with. One of the most inviolable laws in the Universe is the second law of thermodynamics: that in any […]

Are atoms, humans, planets, and galaxies destined to expand, too? One of the most revolutionary discoveries of the past century was the fact that the Universe is not eternally static and […]

We still don’t know how the information encoded onto it gets out. No matter what you do in the Universe, its overall entropy always increases. Even when we put things in […]

And do our black holes give birth to baby Universes? When it comes to our understanding of the Universe, the 20th century was full of surprises. A little over 100 […]

Yes, we’d all die. But for 21 minutes, we’d have the ride of a lifetime. One of the most remarkable facts about the Universe is this: in the absence of […]

Despite the claims of one of Earth’s newest Nobel Laureates, the data doesn’t lie. One of the greatest scientific successes of the past century was the theory of the hot Big […]