Browsed by
Category: Physics

What is entropy? A measure of just how little we really know

What is entropy? A measure of just how little we really know

Zack Savitsky writes: Life is an anthology of destruction. Everything you build eventually breaks. Everyone you love will die. Any sense of order or stability inevitably crumbles. The entire universe follows a dismal trek toward a dull state of ultimate turmoil. To keep track of this cosmic decay, physicists employ a concept called entropy. Entropy is a measure of disorderliness, and the declaration that entropy is always on the rise — known as the second law of thermodynamics — is…

Read More Read More

Scientists reveal the shape of a single photon for the first time

Scientists reveal the shape of a single photon for the first time

SciTechDaily reports: A groundbreaking quantum theory has allowed researchers to define the exact shape of a single photon for the first time. Scientists at the University of Birmingham, whose work is featured in Physical Review Letters, have delved into the intricate behavior of photons — individual particles of light. Their research reveals how photons are emitted by atoms or molecules and how their shape is influenced by the surrounding environment. This complex interaction gives rise to infinite possibilities for light…

Read More Read More

In the quantum world, even points of view are uncertain

In the quantum world, even points of view are uncertain

Anil Ananthaswamy writes: Imagine standing on a railway platform watching a trolley go past. A girl on the trolley drops a bright red ball. To her, the ball falls straight down. But from the platform, you see the ball traverse an arc before hitting the trolley floor. The two of you observe the same event, but from different reference frames: one anchored to the trolley and the other to the platform. The idea of reference frames has a storied history…

Read More Read More

A new field theory reveals the hidden forces that guide us

A new field theory reveals the hidden forces that guide us

Daniel W McShea and Gunnar O Babcock write: Why do rocks fall? Before Isaac Newton introduced his revolutionary law of gravity in 1687, many natural scientists and philosophers thought that rocks fell because falling was an essential part of their nature. For Aristotle, seeking the ground was an intrinsic property of rocks. The same principle, he argued, also explained why things like acorns grew into oak trees. According to this explanation, every physical object in the Universe, from rocks to…

Read More Read More

Black holes could be the mysterious force expanding the Universe

Black holes could be the mysterious force expanding the Universe

Science Alert reports: From the winding down of clocks to the death of stars, everything seems destined to eventually grind to a halt. But there’s one really, really big thing to which this doesn’t seem to apply, at all. That’s the Universe itself, getting bigger and bigger all the time. According to our physical descriptions of how the cosmos should behave, that growth should be slowing down. Instead, measurements show it is speeding up, driven by a mysterious force known…

Read More Read More

It might be possible to detect gravitons after all

It might be possible to detect gravitons after all

Charlie Wood writes: Detecting a graviton — the hypothetical particle thought to carry the force of gravity — is the ultimate physics experiment. Conventional wisdom, however, says it can’t be done. According to one infamous estimate, an Earth-size apparatus orbiting the sun might pick up one graviton every billion years. To snag one in a decade, another calculation has suggested, you’d have to park a Jupiter-size machine next to a neutron star. In short: not going to happen. A new…

Read More Read More

Gravity can exist without mass and dark matter could be myth, says study

Gravity can exist without mass and dark matter could be myth, says study

Rupendra Brahambhatt writes: According to the theory of general relativity, a galaxy must have a certain amount of mass to be held together by gravity. However, scientists don’t see enough visible mass in many galaxies in the universe, yet gravity keeps such galaxies intact. How’s this even possible? This is where the concept of dark matter comes into play. Scientists believe that galaxies have invisible mass in the form of matter that doesn’t interact with light. The gravity holding these…

Read More Read More

Quantum physicists discover ‘negative time’ in strange experiment

Quantum physicists discover ‘negative time’ in strange experiment

Live Science reports: Quantum physicists are familiar with wonky, seemingly nonsensical phenomena: atoms and molecules sometimes act as particles, sometimes as waves; particles can be connected to one another by a “spooky action at a distance,” even over great distances; and quantum objects can detach themselves from their properties like the Cheshire Cat from Alice’s Adventures in Wonderland detaches itself from its grin. Now researchers led by Daniela Angulo of the University of Toronto have revealed another oddball quantum outcome:…

Read More Read More

John Wheeler saw the tear in reality

John Wheeler saw the tear in reality

Amanda Gefter writes: When Johnny Wheeler was 4 years old, splashing in the bathtub in Youngstown, Ohio, he looked up at his mother and asked, “What happens when you get to the end of things?” The question would haunt him for the rest of his life. What happens when you get to the bottom of space? What happens when you get to the edge of time? It would lead him to suggest that space-time can’t be the true fabric of…

Read More Read More

In an epic cosmology clash, rival scientists begin to find common ground

In an epic cosmology clash, rival scientists begin to find common ground

Science News reports: The biggest clash in cosmology might be inching closer to resolution, thanks to the James Webb Space Telescope. Scientists disagree over the universe’s expansion rate, known as the Hubble constant. There are two main methods for measuring it — one based on exploding stars called supernovas and the other on the universe’s oldest light, the cosmic microwave background. The two techniques have been in conflict for a decade, in what’s known as the “Hubble tension.” If this…

Read More Read More

Does chaos theory square classical physics with human agency?

Does chaos theory square classical physics with human agency?

Erik Van Aken writes: A slight shift in Cleopatra’s beauty, and the Roman Empire unravels. You miss your train, and an unexpected encounter changes the course of your life. A butterfly alights from a tree in Michoacán, triggering a hurricane halfway across the globe. These scenarios exemplify the essence of ‘chaos’, a term scientists coined during the middle of the 20th century, to describe how small events in complex systems can have vast, unpredictable consequences. Beyond these anecdotes, I want…

Read More Read More

Physicists pinpoint the quantum origin of the greenhouse effect

Physicists pinpoint the quantum origin of the greenhouse effect

Joseph Howlett writes: In 1896, the Swedish physicist Svante Arrhenius realized that carbon dioxide (CO2) traps heat in Earth’s atmosphere — the phenomenon now called the greenhouse effect. Since then, increasingly sophisticated modern climate models have verified Arrhenius’ central conclusion: that every time the CO2 concentration in the atmosphere doubles, Earth’s temperature will rise between 2 and 5 degrees Celsius. Still, the physical reason why CO2 behaves this way has remained a mystery, until recently. First, in 2022, physicists settled…

Read More Read More

‘Metaphysical experiments’ probe our hidden assumptions about reality

‘Metaphysical experiments’ probe our hidden assumptions about reality

Amanda Gefter writes: Metaphysics is the branch of philosophy that deals in the deep scaffolding of the world: the nature of space, time, causation and existence, the foundations of reality itself. It’s generally considered untestable, since metaphysical assumptions underlie all our efforts to conduct tests and interpret results. Those assumptions usually go unspoken. Most of the time, that’s fine. Intuitions we have about the way the world works rarely conflict with our everyday experience. At speeds far slower than the…

Read More Read More

The physics of cold water may have jump-started complex life

The physics of cold water may have jump-started complex life

Veronique Greenwood writes: Once upon a time, long ago, the world was encased in ice. That’s the tale told by sedimentary rock in the tropics, many geologists believe. Hundreds of millions of years ago, glaciers and sea ice covered the globe. The most extreme scenarios suggest a layer of ice several meters thick even at the equator. This event has been called “Snowball Earth,” and you’d think it would be a terrible time to be alive — and maybe, for…

Read More Read More

The human brain’s complexity teeters at the edge of chaos, physicists say

The human brain’s complexity teeters at the edge of chaos, physicists say

Science Alert reports: The human brain is said to be the most complex object in the known Universe. Its 89 billion neurons each have around 7,000 connections on average, and the physical structure of all those entities may be balanced precariously on a knife’s edge, according to a new study. Two physicists at Northwestern University in the US – Helen Ansell and István Kovács – have now used statistical physics to explain the complexity seen in a highly detailed 3D…

Read More Read More

The new math of how large-scale order emerges

The new math of how large-scale order emerges

Philip Ball writes: A few centuries ago, the swirling polychromatic chaos of Jupiter’s atmosphere spawned the immense vortex that we call the Great Red Spot. From the frantic firing of billions of neurons in your brain comes your unique and coherent experience of reading these words. As pedestrians each try to weave their path on a crowded sidewalk, they begin to follow one another, forming streams that no one ordained or consciously chose. The world is full of such emergent…

Read More Read More