When stars get ejected from galaxies within massive clusters, they go where the dark matter is. Dark matter is one of the greatest mysteries in the Universe, displaying its effects in […]

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 laws of physics are not time-reversal invariant. Here’s how we know. No matter when, where, or what you are in the Universe, you experience time in only one direction: forwards. […]

From explosions to their unique and vibrant colors, the fireworks displays we adore require quantum physics. This Thursday, July 4, 2019, is remarkable for a number of reasons. It happens to […]

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 […]

If you think nothing can move faster than light, check out this clever way to defeat that limit. Nothing can move faster than the speed of light. When Einstein set forth […]

The remote volcano Raikoke just erupted after nearly 100 years of silence. Here’s why it matters. On June 22, 2019, a volcano that had been dormant and inactive for nearly a […]

Here are four separate ways you can prove it, even 50 years after-the-fact. 50 years ago, on July 20, 1969, humanity took our first footsteps on the surface of another […]

Discovered by NASA’s Chandra X-ray observatory, it’s powered by a supermassive black hole. 2019 marks 20 years of NASA’s Chandra, humanity’s most powerful X-ray observatory. Artist illustration of the Chandra X-ray […]

The summer solstice is the longest day of the year, but doesn’t have the earliest sunrise or the latest sunset. Here’s why. The length of a day on planet Earth might […]

It’s where Earth’s axial tilt with respect to the Sun is most extreme. Here are the consequences. Today is June 21st, 2019: the day of the solstice. Although there are […]

Some galaxies might not have any dark matter. Here’s why you should care. There are two assumptions that everyone makes about the Universe for extremely good reasons, but they might not […]

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 […]

If you thought that diamonds were the hardest things of all, this will have you thinking again. Carbon is one of the most fascinating elements in all of nature, with chemical […]

At the core of the largest star-forming region of the Local Group sits the biggest star we know of. Mass is the single most important astronomical property in determining the lives […]

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 […]

An entire Universe of possibilities await stars like our own, even after they run out of fuel. One of the most profound rules in all the Universe is that nothing lasts […]

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 […]

If we could see in three dimensions instead of two, we’d never have thought otherwise. Perhaps the most famous sight of a dying star is the Ring Nebula, discovered in […]

13.8 billion years isn’t close to enough time, but if we wait long enough, even our Sun will become one. The Big Bang happened approximately 13.8 billion years ago, and it […]