All posts tagged: Physics

The big idea: are we about to discover a new force of nature? | Physics

The big idea: are we about to discover a new force of nature? | Physics

Published by skeptic

Modern physics deals with some truly mind-boggling extremes of scale. Cosmology reveals the Earth as a tiny dot amid an observable universe that is a staggering 93bn light years across. Meanwhile, today’s particle colliders are exploring a microcosmic world billions of times smaller than the smallest atom. These two extremes, the biggest and smallest distances probed by science, are separated by 47 orders of magnitude. That’s one with 47 zeros after it, a number so ludicrously huge that it isn’t worth trying to get your head around. And yet, despite exploring such radically different distances and phenomena, cosmology and particle physics are deeply connected. Observing the motions of stars and galaxies can reveal the influence of as-yet-undiscovered particles, while studying fundamental particles in the lab can tell us about the birth and evolution of the cosmos. Intriguingly, both disciplines are grappling with unexplained results that could be pointing to the existence of a new force of nature. If such a new force were to be confirmed, the implications for our understanding of the universe, its …

The Quest to Map the Inside of the Proton

The Quest to Map the Inside of the Proton

Published by skeptic

“How are matter and energy distributed?” asked Peter Schweitzer, a theoretical physicist at the University of Connecticut. “We don’t know.” Schweitzer has spent most of his career thinking about the gravitational side of the proton. Specifically, he’s interested in a matrix of properties of the proton called the energy-momentum tensor. “The energy-momentum tensor knows everything there is to be known about the particle,” he said. In Albert Einstein’s theory of general relativity, which casts gravitational attraction as objects following curves in space-time, the energy-momentum tensor tells space-time how to bend. It describes, for instance, the arrangement of energy (or, equivalently, mass)—the source of the lion’s share of space-time twisting. It also tracks information about how momentum is distributed, as well as where there will be compression or expansion, which can also lightly curve space-time. If we could learn the shape of space-time surrounding a proton, Russian and American physicists independently worked out in the 1960s, we could infer all the properties indexed in its energy-momentum tensor. Those include the proton’s mass and spin, which are …

Can You Really Run on Top of a Train, Like in the Movies?

Can You Really Run on Top of a Train, Like in the Movies?

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Just because you see something done in a movie, that doesn’t mean you should try it yourself. Take, for example, a human running on top of a moving train. For starters, you can’t be sure it’s real. In early Westerns, they used moving backdrops to make fake trains look like they were in motion. Now there’s CGI. Or they might speed the film up to make a real train look faster than it really is. So here’s a question for you: Is it possible to run on a train roof and leap from one car to the next? Or will the train zoom ahead of you while you’re in the air, so that you land behind where you took off? Or worse, would you end up falling between the cars because the gap is moving forward, lengthening the distance you have to traverse? This, my friend, is why stunt actors study physics. Framing the Action What is physics anyway? Basically it’s a set of models of the real world, which we can use to calculate …

Peter Higgs was one of the greats of particle physics. He transformed what we know about the building blocks of the universe

Peter Higgs was one of the greats of particle physics. He transformed what we know about the building blocks of the universe

Published by skeptic

Peter Higgs, who gave his name to the subatomic particle known as the Higgs boson, has died aged 94. He was always a modest man, especially when considering that he was one of the greats of particle physics – the area of science concerned with the building blocks of matter. In 1964, a few years after arriving from London to take up a position at the University of Edinburgh, Higgs read a paper by the American theoretical physicist Philip Anderson. At the time, physicists did not have a theory for how subatomic particles got their mass. (Mass can be described as the total amount of matter in an object, while weight is the force of gravity acting on an object.) Anderson’s paper showed that particles can have mass. When a system in physics – such as two different subatomic particles – becomes changed, physicists sometimes describe it as having “broken symmetry”. This can lead to the emergence of new properties. During a walk in the Scottish Highlands, Higgs had the idea of a lifetime. He …

Physicists created an imaginary magnetic field in real life

Physicists created an imaginary magnetic field in real life

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Physicists have used light to make the imaginary measurable Borkin Vadim/Shutterstock It should be impossible to measure an imaginary number in the lab, but a group of researchers have found a way to do so. They produced the equivalent of a magnetic field of imaginary strength, meaning the imaginary quantities in their experiment were measurable. Imaginary numbers are defined as the square root of a negative number, which is a value that shouldn’t be able to show up on the dials of a measuring instrument. This may make imaginary numbers seem like… Source link

19th-century physics seemed complete. Kelvin thought otherwise

19th-century physics seemed complete. Kelvin thought otherwise

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Key Takeaways In the late 19th century, physicists came to grips with electricity and magnetism. Further discoveries surrounding the atom led some to believe they were close to understanding the “grand underlying principles” of physics in their entirety. However, Lord Kelvin and others perceived two “clouds” looming over the horizon of physics. This has been adapted from QUANTA and FIELDS: The Biggest Ideas in the Universe by Sean Carroll with permission of Dutton, an imprint of Penguin Publishing Group, a division of Penguin Random House LLC. © 2024 by Sean Carroll As the nineteenth century drew to a close, you would have forgiven physicists for hoping that they were on track to understand everything. The universe, according to this tentative picture, was made of particles that were pushed around by fields. The idea of fields filling space had taken off throughout the 1800s. Earlier, Isaac Newton had presented a beautiful and compelling theory of motion and gravity, and Pierre-Simon Laplace had shown how we could reformulate that theory in terms of a gravitational field stretching …

Physicists have worked out how to melt any material

Physicists have worked out how to melt any material

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Predicting when solids will melt is more difficult than you might think r.classen/Shutterstock Physicists may finally have an answer for a seemingly simple question that has remained unanswered for about a century: when does a substance melt? Kostya Trachenko at Queen Mary University of London found it mysterious that “in this age of scientific and technological development”, physicists do not always know how to predict at what temperature and pressure a material will melt. He has now derived an equation that can be used to make such predictions for a vast… Source link

Particle physics finally charts a healthy path forward

Particle physics finally charts a healthy path forward

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Just a decade ago, the field of particle physics looked to be in a state of chaos. The Large Hadron Collider had recently turned on, and although they found the Higgs boson — the final undiscovered particle predicted by the Standard Model — it failed to turn up any evidence for any of the other leading theories that would take us beyond the Standard Model. Fermilab, the prior leader in the energy frontier, shut down its main accelerator permanently, and puzzles such as: the origin of neutrino mass, the nature of dark matter, and the origin of the matter-antimatter asymmetry, seemed to be stagnating, with little progress to show on either the experimental or theoretical fronts. Moreover, particle physicists themselves seemed to be bickering and in disarray as to what they should do next. Would there be enough value to justify a new, more powerful accelerator than the Large Hadron Collider? How should we be probing the behavior of neutrinos in order to understand neutrino mass? Are we taking sufficient advantage of the connection between …