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Category: Physics

Genes harness physics to help grow living things

Genes harness physics to help grow living things

Anna Demming writes: Sip a glass of wine, and you will notice liquid continuously weeping down the wetted side of the glass. In 1855, James Thomson, brother of Lord Kelvin, explained in the Philosophical Magazine that these wine “tears” or “legs” result from the difference in surface tension between alcohol and water. “This fact affords an explanation of several very curious motions,” Thomson wrote. Little did he realize that the same effect, later named the Marangoni effect, might also shape…

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The universe began with the Big Bang and is predicted to end with a Big Crunch

The universe began with the Big Bang and is predicted to end with a Big Crunch

Science Alert reports: If recent discoveries that dark energy is evolving hold any water, our Universe will collapse under its own gravity on a finite timeline, new calculations suggest. Based on several recent dark energy results, a new model finds that the Universe has a lifespan of just 33.3 billion years. Since we are now 13.8 billion years after the Big Bang, this suggests that we have a smidge less than 20 billion years left. For another 11 billion years,…

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Reality isn’t made up of objects

Reality isn’t made up of objects

Dennis Dieks writes: The world we perceive every day is full of things, objects, which we can distinguish from one another, follow in time, and often grasp and manipulate. This experiential fact so imposes itself on us that it is hard to imagine a world without objects. How could we reach out and make contact with the external world if there were no things to touch and see? It is no wonder, then, that from the very beginning of natural…

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Nearly half of the universe’s ordinary matter was uncharted, until now

Nearly half of the universe’s ordinary matter was uncharted, until now

Science News reports: Nearly half of the universe’s ordinary matter has been hiding — until now. Bursts of radio waves have illuminated the whereabouts of all ordinary matter, revealing its distribution between, around and within galaxies, researchers report June 16 in Nature Astronomy. And X-rays have uncovered details about a once hidden string of gas linking four galaxy clusters, another team reports in the June Astronomy and Astrophysics. “The two papers are very complementary,” says astrophysicist Jason Hessels of McGill…

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Why the empty-atom picture misunderstands quantum theory

Why the empty-atom picture misunderstands quantum theory

Mario Barbatti writes: The camera zooms in on the person’s arm to reveal the cells, then a cell nucleus. A DNA strand grows on the screen. The camera focuses on a single atom within the strand, dives into a frenetic cloud of rocketing particles, crosses it, and leaves us in oppressive darkness. An initially imperceptible tiny dot grows smoothly, revealing the atomic nucleus. The narrator lectures that the nucleus of an atom is tens of thousands of times smaller than…

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How the universe differs from its mirror image

How the universe differs from its mirror image

Zack Savitsky writes: After her adventures in Wonderland, the fictional Alice stepped through the mirror above her fireplace in Lewis Carroll’s 1871 novel Through the Looking-Glass to discover how the reflected realm differed from her own. She found that the books were all written in reverse, and the people were “living backwards,” navigating a world where effects preceded their causes. When objects appear different in the mirror, scientists call them chiral. Hands, for instance, are chiral. Imagine Alice trying to…

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How migrating birds use quantum mechanics to navigate

How migrating birds use quantum mechanics to navigate

The Observer reports: To the seasoned ear, the trilling of chiffchaffs and wheatears is as sure a sign of spring as the first defiant crocuses. By March, these birds have started to return from their winter breaks, navigating their way home to breeding grounds thousands of kilometres away – some species returning to home territory with centimetre precision. Although the idea of migration often conjures up striking visions of vast flocks of geese and murmurations of starlings, “the majority,” says…

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Quantum physicists find evidence of ‘negative time’

Quantum physicists find evidence of ‘negative time’

AFP reports: Scientists have long known that light can sometimes appear to exit a material before entering it – an effect dismissed as an illusion caused by how waves are distorted by matter. Now, researchers at the University of Toronto, through innovative quantum experiments, say they have demonstrated that “negative time” isn’t just a theoretical idea – it exists in a tangible, physical sense, deserving closer scrutiny. The findings, yet to be published in a peer-reviewed journal, have attracted both…

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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…

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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…

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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…

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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…

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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…

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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…

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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…

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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:…

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