A Thermometer for Measuring Quantumness

If there’s one law of physics that seems easy to grasp, it’s the second law of thermodynamics: Heat flows spontaneously from hotter bodies to colder ones. But now, gently and almost casually, Alexssandre de Oliveira Jr. has just shown me I didn’t truly understand it at all. Take this hot cup of coffee and this… Continue reading A Thermometer for Measuring Quantumness

The Quantum Mechanics of Greenhouse Gases

There’s a simple story of the greenhouse effect: A blanket of carbon dioxide envelops the planet, letting sunlight in but trapping its heat. As a result, Earth warms. But how does this actually work? Carbon dioxide amounts to only a tiny smattering of gas molecules — 0.042%, or roughly 420 parts per million — in… Continue reading The Quantum Mechanics of Greenhouse Gases

Astrophysicists Find No ‘Hair’ on Black Holes

In 2012, physicists showed that this paradox is tightly linked to the nature of the event horizon. They’d known since the 1970s that black holes emit radiation, and that this radiation probably somehow carries the scrambled information about the stuff that fell into the hole. Now they imagined what would happen if an astronaut who… Continue reading Astrophysicists Find No ‘Hair’ on Black Holes

Matter vs. Force: Why There Are Exactly Two Types of Particles

Beneath the richness of our world lies a pristine simplicity. Everything is made of a set of just 17 fundamental particles, and those particles, though they may differ by mass or charge, come in just two basic types. Each is either a “boson” or a “fermion.” The physicist Paul Dirac coined both terms in a… Continue reading Matter vs. Force: Why There Are Exactly Two Types of Particles

Can Quantum Gravity Be Created in the Lab?

Quantum gravity is one of the biggest unresolved and challenging problems in physics, as it seeks to reconcile quantum mechanics, which governs the microscopic world, and general relativity, which describes the macroscopic world of gravity and space-time. Efforts to understand quantum gravity have been focused almost entirely at the theoretical level, but Monika Schleier-Smith at… Continue reading Can Quantum Gravity Be Created in the Lab?

‘Next-Level’ Chaos Traces the True Limit of Predictability

The French scholar Pierre-Simon Laplace crisply articulated his expectation that the universe was fully knowable in 1814, asserting that a sufficiently clever “demon” could predict the entire future given a complete knowledge of the present. His thought experiment marked the height of optimism about what physicists might forecast. Since then, reality has repeatedly humbled their… Continue reading ‘Next-Level’ Chaos Traces the True Limit of Predictability

New Maps of the Bizarre, Chaotic Space-Time Inside Black Holes

At the beginning of time and the center of every black hole lies a point of infinite density called a singularity. To explore these enigmas, we take what we know about space, time, gravity and quantum mechanics and apply it to a place where all of those things simply break down. There is, perhaps, nothing… Continue reading New Maps of the Bizarre, Chaotic Space-Time Inside Black Holes

Do We Really Live in the Darkest Timeline?

As memes go, it wasn’t particularly viral. But for a couple of hours on the morning of November 6, the term “darkest timeline” trended in Google searches, and several physicists posted musings on social media about whether we were actually in it. All the probabilities expressed in opinion polls and prediction markets had collapsed into… Continue reading Do We Really Live in the Darkest Timeline?

‘Quantum Memory’ Proves Exponentially Powerful

It’s not easy to study quantum systems — collections of particles that follow the counterintuitive rules of quantum mechanics. Heisenberg’s uncertainty principle, a cornerstone of quantum theory, says it’s impossible to simultaneously measure a particle’s exact position and its speed — pretty important information for understanding what’s going on. In order to study, say, a… Continue reading ‘Quantum Memory’ Proves Exponentially Powerful