Category: SCIENCE

From our own perspective on Earth, we’ve identified the presence of spiral arms.

However, being stuck within the Milky Way itself, we exclusively view it edge-on.

Even our best spaceborne views leave much ambiguity in our galaxy’s overall structure.

Electromagnetism, both nuclear forces, and even the Higgs force are mediated by known bosons. What about gravity? Does it require gravitons?

If you examine the Universe extremely closely, by probing the fundamental entities with it on the smallest possible scales, you’ll discover that reality is fundamentally quantum in nature. Matter itself is made up of indivisible, uncuttable quantum entities: particles like quarks, leptons, and bosons. These quanta have charges (color charge, electric charge, weak isospin and weak hypercharge, and “mass/energy” as a gravitational charge), and it’s the exchange of quanta between these charged particles (gluons, photons, W-and-Z bosons, etc.) that mediate these forces. There’s even a Higgs force as well.

However, one type of quantum that’s never been detected is the graviton: the theoretical particle that mediates the gravitational force. Even though it’s predicted to exist (and to have a spin of 2, unique among all particles) and, just like light is composed of photons, gravitational waves should be composed of gravitons, those predictions rely on an unproven assumption: that gravity is fundamentally a quantum force in nature. Is that assumption necessarily true? It isn’t in Einstein’s General Relativity, and that prompted…

Matt Strassler’s journey into fundamental physics culminates in a brilliant explanation of the Higgs field. Enjoy this exclusive interview.

It’s rare that a book comes along that changes the way experts in their field think about the fundamentals, while simultaneously being accessible and informative to those without expert knowledge themselves. That’s why, as 2024 winds down, it’s a no-brainer selection to choose Matt Strassler’s incomparable new book, Waves in an Impossible Sea: How everyday life emerges from the cosmic ocean, as this year’s best science book. (Yes, even in a year where I myself wrote my own book!) Strassler, a world-renowned expert in particle physics in his own right (and longtime science blogger), takes the reader on a whirlwind tour of physics from a conceptual point of view.

Even classic topics such as Galileo’s relativity and Newtonian gravity are presented in novel, accessible ways, with common historical terms like “Newton’s first law” replaced by the more intuitive ones such as the “coasting law.” Strassler takes the reader on similar journeys through other classical topics such as mass, waves, and fields before entering the more unfamiliar world of the quantum, which suddenly seems more…

By improving quantum error correction, quantum computations are now faster than ever. But parallel universes? That’s utter nonsense here.

Quantum computation is, simultaneously, a remarkable scientific achievement with the potential to solve an array of problems that currently are wholly impractical to solve, and also a breathless source of wild, untrue claims that completely defy reality. In 2021, there were claims that Google’s quantum computing team developed a time crystal that violated the laws of thermodynamics. (The first part is true, the second is not.) In late 2022, a team claimed to demonstrate the existence of wormholes using a quantum computer, which was incorrect across the board. And now, here in 2024, Google has introduced a new quantum chip, Willow, that the founder and lead of Google’s Quantum AI states proves the existence of parallel universes.

Do you sense a pattern here? Are you a little suspicious of such a wild claim? Well, you should be. Whitney Clavin certainly is, as she wrote to me to ask:

“Have you seen all this crazy talk about Google’s quantum computing breakthrough providing evidence for the multiverse?! Google said this! I think you need to write a story…

If atoms are mostly empty space, then why can’t two objects made of atoms simply pass through each other? Quantum physics explains why.

Here on planet Earth, as well as in most locations in the Universe, everything we observe and interact with is made up of atoms. Atoms come in roughly 90 different naturally occurring species, where all atoms of the same species share similar physical and chemical properties, but that differ tremendously from one species to another. Once thought to be indivisible units of matter, we now know that atoms themselves have an internal structure, with a tiny, positively charged, massive nucleus consisting of protons and neutrons surrounded by negatively charged, much less massive electrons. We’ve measured the physical sizes of these subatomic constituents exquisitely well, and one fact stands out: the size of atoms, at around 10^-10 meters apiece, are much, much larger than the constituent parts that compose them.

Protons and neutrons, which compose the atom’s nucleus, are roughly a factor of 100,000 smaller in length, with a typical size of only around 10^-15 meters. Electrons are even smaller, and are assumed to be point-like particles in the sense that they exhibit no measurable size at all, with experiments…

Even with just a momentary view of our galaxy right now, the data we collect enables us to reconstruct so much of our past history.

When we look out at our home galaxy, the Milky Way, we have to recognize that even though it’s been growing and evolving for 13.8 billion years, we’re only observing it as it is right now: a snapshot in time determined by the light that’s arriving in our instruments right now. However, just like we’re living “right now” in human history but can, through the science of archaeology, learn about historical events that happened many thousands of years ago (before recorded history) or even earlier, we can learn about the Milky Way’s history through the astronomical equivalent: galactic archaeology.

The closest known star that will soon undergo a core-collapse supernova is Betelgeuse, just 640 light-years away. Here’s what we’ll observe.

The stars in the night sky, as we typically perceive them, are normally static and unchanging to our eyes. Sure, there are variable stars that brighten and fainten, but most of those do so periodically and regularly, with only a few exceptions. One of the most prominent exceptions is Betelgeuse, the red supergiant that makes up one of the “shoulders” of the constellation Orion. Over the past five years, not only has it been fluctuating in brightness, but its dimming in late 2019 and early 2020, followed by a strange brightening in 2023, indicates variation in a fashion never before witnessed by living humans.

Betelgeuse is typically the 10th brightest star in our sky, but fell out of the top 20 during its faintest in 2020 and rose as high as the 7th brightest in 2023. As a red supergiant, it’s only a matter of time before it undergoes a core-collapse supernova, although no one known how to predict when that will occur. There’s no scientific reason to believe that Betelgeuse is in any more danger of going supernova today than at any random day over the next ~100,000 years or so, but many of us —…

The Sombrero is the closest bright, massive, edge-on galaxy to us. JWST’s new image, taken with MIRI, finally shows what’s under its hat.

Since its discovery nearly 250 years ago, the Sombrero galaxy has delighted astronomers.

It appears nearly edge-on, inclined at a mere 6°.

Intrinsically, it’s the brightest known galaxy within 35 million light-years.

Puzzlingly, it displays features of both spiral and elliptical galaxies.

Prominent dust lanes and spiral arms line a central disk.

One of the fundamental constants of nature, the fine-structure constant, determines so much about our Universe. Here’s why it matters.

There’s an enormous existential question that we’ve wondered about ever since we first realized that the Universe does, in fact, obey physical laws at all: why is our Universe the precise way it is, rather than any other way we could’ve imagined? There are only three things that make it so:

• the laws of nature themselves,
• the fundamental constants governing reality,
• and the initial conditions that our Universe was born with.

If our Universe had different laws of nature, then all bets would be off; the cosmos would have been vastly different in almost any way you can fathom. Protons might decay, fundamental quantities like particle masses might not be constant, and the strengths of any fundamental forces might joltingly change at any moment.

If only the initial conditions of our Universe were different, the way the cosmic story unfolded would be the same in terms of broad strokes, but the details would differ between that hypothetical Universe and our own. But for the fundamental constants, some changes would be…

Two parts of our Universe that seem to be unavoidable are dark matter and dark energy. Could they really be two aspects of the same thing?

When it comes to the Universe, what you can easily see isn’t always reflective of all there is. It’s one of the important reasons why theories and observations/measurements need to go hand-in-hand: observations tell you what’s there to the best of our measurement capabilities, and theory allows us to compare what we’d expect to occur versus what’s actually seen. When they match up, that’s generally an indication that we have a pretty good understanding of what’s actually going on. But when they don’t, that’s a sign that one of two things is occurring:

• either the theoretical rules we’re applying aren’t quite right for this situation,
• or there are additional ingredients out there that our observations haven’t directly revealed.

Many of the biggest mismatches in the Universe — between what we observe and what we would have expected based solely on what we see — point to two additional ingredients: dark matter and dark energy. But these two seemingly unrelated phenomena have something deeply disconcerting in common: they’ve only ever been detected…