With every second that goes by, tens of thousands of star disappear from our reach. And it’s getting worse. It’s been nearly a century since scientists first theorized that the Universe […]

The Universe was born matter-antimatter symmetric. Here’s what happened when the last of our antimatter disappeared. Things happen fast in the earliest stages of the Universe. In the first 25 […]

The Universe is an enormous place, but we can’t see all the way back to the beginning. Here’s the latest record-breaker. No matter how far back we look in the […]

In General Relativity, even space and time themselves aren’t what they seem. Gravity might have been the first fundamental force ever discovered, but in many ways, it remains the least-well understood. […]

Space may be enormous, but collisions are inevitable. Here’s what happens when they occur. The Universe as we know it has been around for nearly 14 billion years: plenty of time […]

The ices and rock aren’t green, and neither are the tails. So where does a comet’s green color come from? Every so often, with extreme regularity, comets will plunge from beyond […]

It wasn’t just the Milky Way and Andromeda two billion years ago. Here in the Local Group, our two largest galaxies dominate: Andromeda and the Milky Way. Our Local Group of […]

Did the Universe begin at time t=0? Did space and time emerge from that? The Universe, today, is expanding and cooling, as the volume of the Universe increases while the number […]

The Universe was born with equal amounts of matter and antimatter. How did matter win? 13.8 billion years ago, at the moment of the Big Bang, the Universe was the hottest […]

If we know how big the observable Universe is, why can’t we figure out how big the unobservable part is? 13.8 billion years ago, the Big Bang occurred. The Universe was […]

The most unusual star known has finally had its dimming scientifically explained. Here’s the unusual, dusty resolution. The science of planet-hunting has truly taken off in the 21st century, with […]

In 1987, we detected neutrinos from another galaxy in a supernova. After a 30 year wait, we’ve found something even better. One of the great mysteries in science is determining not […]

Immediately after the Big Bang, the Universe was more energetic than ever. What was it like? When we look out at the Universe today, we see that it’s full of stars […]

The brightest galaxies of all neither have the most stars nor the biggest black holes. Here’s how to solve the mystery. With some 400 billion stars burning steadily, the Milky Way […]

How ‘special’ are we for life to have survived and thrived the way it did? While there are hundreds of billions of stars in our galaxy, many with Earth-sized planets at […]

Finding the ingredients for life is a very different prospect than finding the products of life. Perhaps the greatest quest in science today is to find life that originated beyond Earth. […]

There’s a halo of dark matter permeating every galaxy, and that means its particles pass through us, too. The Universe, despite all the planets, stars, gas, dust, galaxies, and more we […]

Forget the spectacular explosions we create here on Earth. The Universe outdoes us in every way imaginable. Forget mere chemical reactions; in space, matter-energy conversion creates unprecedentedly powerful explosive events. […]

Dark energy is pushing distant galaxies apart from one another at an increasing rate. If the Big Rip hypothesis is true, things will only get worse from here. One of the […]

Cosmic inflation is what happened before, and set up, the Big Bang. Here’s what it’s like to live in an inflating Universe. Our Universe today is full of matter and […]

Many hoped we could do without dark matter. On cosmic scales, the evidence has finally spoken. For over 40 years, scientists have argued over dark matter’s existence. The extended rotation curve […]

What’s going on at the smallest and largest scales of all? Let’s look to the absolute limits of physics. Have you ever wondered what’s out there in the Universe, on the […]

The Universe is expanding, but different techniques can’t agree on how fast. No matter what, something major has got to give. Look out at a distant galaxy, and you’ll see it […]

If you thought LIGO’s recent discoveries were profound and unusual, wait until you meet OJ 287. Recently, LIGO has revolutionized our knowledge of the Universe by discovering merging black holes. The […]

There’s no such thing as a theory that’s too beautiful to be wrong, if it doesn’t agree with experiment. The history of physics is filled with great ideas that you’ve […]

When it comes to the Solar System, all we have left are the survivors. At last, that might be enough to know what happened 4.5 billion years ago. We know what […]

Even before we have the James Webb Space Telescope, a controversy over when the first stars formed is growing. As far back as our most powerful telescopes have ever looked, we’ve […]

If dark energy were stronger or weaker, everything would be pretty much the same. And that’s a puzzle. After the Big Bang, the Universe was full of matter and radiation. It […]

One of the night sky’s most famous sights isn’t what it appears to be. Perhaps the most famous sight of a dying star is the Ring Nebula, known since 1779. The […]

Dark energy tells us that the Universe’s expansion is accelerating. Here’s what that means for our disappearing Universe. One of the biggest surprises for humanity about the Universe is that […]