Maybe, but that probably doesn’t mean what you think it does. Of all the unsolved puzzles in the Universe, perhaps the most confounding is the dark matter problem. If we look […]

You might think that we live in a three dimensional Universe based on space alone. But you cannot leave time out of it. If you were asked to describe how you […]

Black holes are regions of extreme gravity, but dark matter barely interacts at all. Do they play well together? Black holes are some of the most extreme objects in the […]

When the Universe expands, photons redshift to longer wavelengths and lower energies. So where does that energy go? Imagine the ultimate version of a toy Universe: it’s expanding, it’s full of […]

A star orbiting past our galaxy’s supermassive black hole offered a chance to test relativity as never before. The supermassive black hole at the center of the Milky Way is the […]

Particle physics is everywhere, even in the palm of your hand. When you hold out your palm and point it towards the sky, what is it that’s interacting with your hand? […]

And does it require the idea of ‘negative gravity’ in order to work? The biggest question that we’re even capable of asking, with our present knowledge and understanding of the Universe, […]

It’s very different from the colloquial meanings of “true-and-false” or “right-and-wrong.” In many ways, the human endeavor of science is the ultimate pursuit of truth. By asking the natural world […]

General Relativity has nothing to do with light or electromagnetism at all. So how to gravitational waves know to travel at the speed of light? There are two fundamental classes of […]

The quest for a quantum theory of gravity is the holy grail of physics. Here’s why it’s murkier than anyone expected. If you want to fully describe how the Universe […]

The Planck length is a lot smaller than anything we’ve ever accessed. But is it a true limit? If you wanted to understand how our Universe operates, you’d have to examine […]

A vacuum cleaner is the wrong picture. Time to bust that myth. There are no classes of object in our Universe more extreme than black holes. With so much mass present […]

Two independent techniques give precise but incompatible answers. Here’s how to resolve it. If you didn’t know anything about the Universe beyond our own galaxy, there are two different pathways you […]

Has the mystery really been solved? Doubtful. The real science goes much deeper. For perhaps the last year or so, a small galaxy located not too far away has captivated the […]

When we think about the birth of the Universe, was time already in place? When we look at the Universe today, we know with an extraordinary amount of scientific certainty that […]

The solar eclipse of May 29, 1919, was the nail in the coffin of a Newtonian Universe. On May 29, 1919, the world changed forever. For hundreds of years, Isaac […]

Even the best science imaginable has its limits. In terms of ambition, it’s hard to ask for more than to know absolutely everything there is to know about the Universe. That’s […]

Some claim that inflation isn’t science, but it sure has made some incredibly successful scientific predictions. So, you want to know how the Universe began? You’re not alone. Every other […]

The world’s greatest observatory can go no further with its current instrument set. The Hubble Space Telescope has provided humanity with our deepest views of the Universe ever. It has […]

Dark matter, dark energy, inflation and the Big Bang are real, and the alternatives all fail spectacularly. If you keep up with the latest science news, you’re probably familiar with […]

It’s made up of scores of telescopes at many different sites across the world. But it acts like one giant telescope. Here’s how. If you want to observe the Universe more […]

How fast is the Universe expanding? The results might be pointing to something incredible. If you want to know how something in the Universe works, all you need to do […]

It might be the biggest conundrum facing cosmology today. But perhaps it’s not a controversy; it might be a clue. https://soundcloud.com/ethan-siegel-172073460/starts-with-a-bang-44-the-expanding-universe/ One of the biggest conundrums in the Universe surrounds the […]

And why Einstein’s quest for unification was doomed from the start. If you wanted to answer the question of what’s truly fundamental in this Universe, you’d need to investigate matter and […]

If a star spins and then collapses, what happens to its angular momentum? The most common way to form a black hole in the Universe is to have a massive […]

A single thought experiment reveals a paradox. Could quantum gravity be the solution? Sometimes, if you want to understand how nature truly works, you need to break things down to […]

We’ve put so much together about the Universe. Could it all come tumbling down? We’re always on the lookout for the next big thing, and even our best guesswork is often […]

And what do we still have left to learn? The original idea of a black hole goes all the way back to 1783, when Cambridge scientist John Michell recognized that a […]

The first image of an Event Horizon is here. Here’s what it means. Variety isn’t just the spice of life, but a natural consequence of living in our Universe. Gravitation, obeying […]

We’ve never seen an image of a black hole’s event horizon before. Here’s what we’re expecting, based on what we already know. For hundreds of years, physicists have hypothesized that the […]