If you can’t explain the astrophysical signal that you see and cry ‘dark matter,’ chances are you’re not thinking hard enough. Despite our knowledge of the laws of physics, and the […]

A new look at the intertwined lives of two of the 20th century’s greatest minds. In the years prior to World War II, physics was in an odd, post-revolutionary state. Quantum […]

As wonderful as the evidence that supports or invalidates a theory is, it can never truly kill the ones that don’t work out. When it comes to science, we like to […]

If the gravity isn’t where the matter is, things get into trouble very, very quickly. The above image, a composite of optical data, X-ray data, and a reconstructed mass map, is […]

There are plenty of questions we don’t know the answer to. With quantum gravity, they might be solved! This article is written by Sabine Hossenfelder. Sabine is a theoretical physicist specialized […]

Don’t believe in dark matter or dark energy? Your view of the Universe just got a lot more difficult. If you ask an astrophysicist what’s the greatest puzzle in the […]

Do we need quantum gravity? We sure do… and here’s how we’re trying to get there! Our current best theories describing the Universe, general relativity for gravity, quantum field theory for […]

Very sure. Here’s how we know. You’ve no doubt heard that the Universe itself has been around for 13.8 billion years since the Big Bang, and that scientists are extremely confident […]

All sorts of futuristic technologies have come true. So why are astronauts all still weightless? Put a human being up in space, away from the gravitational bonds of the surface […]

One of cosmic inflation’s cofounders came out against it, calling it not even science. But it is… and so much more. “There’s no obvious reason to assume that the very same […]

It’s a fascinating idea, but how does it fare as a scientific theory? “Something is happening here and this is going to have an impact.” –Robert Dijkgraaf, on Verlinde’s work The […]

A well-deserved award for the discovery over a century in the making. “Well, I walked into Building 20 and looked in at the various little labs. There was a bunch of […]

Three eyes are so much better than two. Here’s why. “Einstein’s gravitational theory, which is said to be the greatest single achievement of theoretical physics, resulted in beautiful relations connecting gravitational […]

From what it’s expanding into to whether things are moving faster-than-light, this clears up some of our greatest misconceptions. “The more clearly we can focus our attention on the wonders […]

Many sci-fi technologies will remain in the realm of fiction unless physics changes. But some experiments could uncover just that! “Imagination makes us aware of limitless possibilities. How many of us […]

When matter falls in, black holes grow. But Hawking radiation says that black holes decay. Who wins? “Maybe that is our mistake: maybe there are no particle positions and velocities, but […]

Gravitational waves and spacetime ripples have so much more to do with the Universe than just merging black holes. “The years of searching in the dark for a truth that one […]

From a Universe that went no bigger than our Milky Way to the trillions of galaxies in our expanding Universe, our knowledge increased one step at a time. “Gamow was fantastic […]

Falling into a black hole is forever… but could a tether to the outside pull you back out? “Nobody ever did, or ever will, escape the consequences of his choices.” –Alfred A. […]

Did they perform their analysis sub-optimally? Maybe. But gravitational waves were seen no matter what. “We hope that interested people will repeat our calculations and will make up their own minds […]

How the Universe’s expansion rate continues to baffle us. “In expanding the field of knowledge we but increase the horizon of ignorance.” –Henry Miller It’s the most fundamental law of special […]

One of inflation’s co-founders lashes out against the community. But is there a scientific leg to stand on? “…an understanding of the infinite tree of universes seems to be needed in […]

A live-blog event happened a week ago, but you can catch the entire thing anew here, right now! “We have never observed infinity in nature. Whenever you have infinities in […]

You might think that it should be all black, but then how would we see it? “It is conceptually interesting, if not astrophysically very important, to calculate the precise apparent shape […]

If it’s the anti-version of normal matter, could it possibly fall “up”? This article was written by Sabine Hossenfelder of Backreaction. Sabine is a theoretical physicist specialized in quantum gravity and […]

What would energy without a particle to attach itself to even look like? “It is only through labor and painful effort, by grim energy and resolute courage, that we move on […]

The answer lies billions of years in the past. “Dark matter or invisible element?You decide.” –Toba Beta When we look out at the luminous matter in the Universe — stars, galaxies, clusters of […]

Space is getting bigger, but atoms, humans, Earth and our Milky Way stay the same size. How is this possible? “The Universe is expanding the way your mind is expanding. […]

The latest challenger to dark matter’s throne may not be so difficult to knock off, after all. This post was written by Sabine Hossenfelder. Sabine is a theoretical physicist specialized in […]

If the Big Bang happened and everything is moving away from us, where’s the center? “I want to stand as close to the edge as I can without going over. Out […]