Keyword: gravity
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More than any other equation in physics, E = mc² is recognizable and profound. But what do we actually learn about reality from it? ===================================================================== This 1934 photograph shows Einstein in front of a blackboard, deriving special relativity for a group of students and onlookers. Although special relativity is now taken for granted, it was revolutionary when Einstein first put it forth, and doesn't even describe his most famous equation, which is E = mc². - Public Domain ====================================================================== Key Takeaways: * First introduced way back in 1905, Einstein’s most famous equation, E = mc², put forth the mathematical formula...
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A recent study that presents new challenges to the existence of dark matter suggests gravity may be able to exist even in the absence of mass. Although all life on Earth experiences its effects daily, gravity remains one of the great mysteries of modern physics. Now, a new study published by Dr. Richard Lieu with The University of Alabama in Huntsville (UAH) proposes that the gravitational effects observed in galaxies and clusters may be the result of what he likens to topological defects in the universe, a theory that does not require the inclusion of dark matter to explain phenomena...
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Discovering a machine that could somehow produce thrust without releasing propellant would be a game-changer for human space travel. There’s just one problem—such a device would defy the laws of physics.
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Opinion The scientific community celebrated April 14 as World Quantum Day to raise awareness of quantum science’s impact across diverse fields The world of science is on the cusp of a transformative era driven by the burgeoning field of quantum technology. Quantum science is founded on several key principles that underpin the behaviour of particles and systems at the quantum scale. The term “quantum scale” refers to the realm of physics that deals with phenomena occurring at very small scales, typically at the level of atoms, subatomic particles and fundamental particles. It encompasses the principles of quantum mechanics, which govern...
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An artist's impression of the experiment. (University of Southampton) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Acting on a tiny particle levitating in a magnetic trap, physicists have just measured the smallest gravitational pull ever recorded. The particle weighed just 0.43 grams. And the strength of the gravitational force at play was on the scale of attonewtons (10-18 newtons). That's small enough to be right on the verge of the quantum realm, teasing the possibility of finally figuring out how classical physics and quantum mechanics interact. "For a century, scientists have tried and failed to understand how gravity and quantum mechanics work together," says physicist Tim...
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President Biden, yet again, has tripped twice while boarding Air Force One — despite using a shorter, less challenging staircase. The 81-year-old commander-in-chief managed to narrowly avoid a complete double tumble as he prepared to set off for Los Angeles on Tuesday. Footage of the near-miss showed Biden saluting US military personnel at the bottom of the staircase before starting his climb at Andrews Air Force Base, Md. About halfway up, the president could be seen tripping slightly on a step. Biden quickly gripped the railing to steady himself but immediately tripped on the following step, too. Social media were...
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The Orion: A molecular cloud shows cosmic filamentary structures where stars are being born. Image: ESA / Herschel / Ph. André, D Polychroni, A. Roy, V Könyves, N Schneider for the Gould Belt survey Key Program ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In the first part of this series, we saw that electromagnetic processes in plasmas – electrically conducting gases – could, over trillions of years, produce the giant filaments that we see today as the largest structures in the universe. This happened without a Big Bang, without dark energy or dark matter, based on processes that we observe here on Earth in the laboratory...
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The Laser Interferometer Gravitational-Wave Observatory (LIGO) has improved its detection of cosmic events by overcoming quantum noise through advanced “squeezing” technology. This breakthrough will increase its detection rate by 60 percent and pave the way for advancements in quantum technology and physics. Researchers using LIGO achieved a landmark in quantum squeezing. In 2015, the Laser Interferometer Gravitational-Wave Observatory, or LIGO, made history when it made the first direct detection of gravitational waves, or ripples in space and time, produced by a pair of colliding black holes. Since then, the U.S. National Science Foundation (NSF)-funded LIGO and its sister detector in...
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A very brief video because I want to tell you about this story I learned from William Jason Morgan's obituary. It's a lovely story about how the process of scientific discovery sometimes takes unexpected turns.He looked for gravitational waves, but discovered something entirely different | 3:39Sabine Hossenfelder | 1.03M subscribers | 232,486 views | October 19, 2023her YouTube channel
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An international team of astrophysicists has made a puzzling discovery while analyzing certain star clusters. The finding challenges Newton's laws of gravity, the researchers write in their publication. Instead, the observations are consistent with the predictions of an alternative theory of gravity. However, this is controversial among experts. The results have now been published in the Monthly Notices of the Royal Astronomical Society. In their work, the researchers investigated open star clusters. These are formed when thousands of stars are born within a short time in a huge gas cloud. As they "ignite," the galactic newcomers blow away the remnants...
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Jordan Hatmaker was skydiving in November when the worst thing that could happen happened: Her parachute didn’t open. The plane was more than 13,000 feet above the ground when she jumped, and she hit the ground at about 80 miles per hour. Hatmaker’s reserve parachute did actually deploy, but it made her main parachute pop out at the same time. “They pulled away from each other in the air and then dragged me down in kind of a spiral motion,” she explained. Once she realized she was going down, Hatmaker had one minute before she hit the ground. Hatmaker believes...
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Microlensing strikes again. Astronomers have been using the technique to detect everything from rogue planets to the most distant star ever seen. Now, astronomers have officially found another elusive object that has long been theorized, and that Universe Today first reported on back in 2009 but has never directly detected – a rogue black hole. That detection comes at the end of a 6-year observational campaign, with dozens of authors collaborating on a paper recently published in arXiv (meaning it has not yet been peer-reviewed). Those six years of painstakingly gathered data all started back in 2011, when a star...
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In a quest to map out a quantum theory of gravity, researchers have used logical rules to calculate how much Einstein’s theory must change. The result matches string theory perfectly. 4 ========================================================================== Quantum gravity researchers use α to denote the size of the biggest quantum correction to Einstein’s general relativity. Recently, three physicists calculated a number pertaining to the quantum nature of gravity. When they saw the value, “we couldn’t believe it,” said Pedro Vieira, one of the three. Gravity’s quantum-scale details are not something physicists usually know how to quantify, but the trio attacked the problem using an approach...
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Gravity-based energy storage technology company Energy Vault has formed a strategic partnership with non-ferrous metals smelting and refinery company Korea Zinc, including a US$50 million investment commitment. The announcement, made yesterday, comes as Swiss-American company Energy Vault targets a business combination with special purpose acquisition company (SPAC) Novus Capital Corporation II. The transaction is expected to close during this quarter and the combined company, to be named Energy Vault Holdings, will list on the New York Stock Exchange (NYSE) as a result. Energy Vault said in October as it announced the intended merger that it has private investment in public...
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A physics problem that has plagued science since the days of Isaac Newton is closer to being solved, say a pair of Israeli researchers. The duo used "the drunkard's walk" to calculate the outcome of a cosmic dance between three massive objects, or the so-called three-body problem. For physicists, predicting the motion of two massive objects, like a pair of stars, is a piece of cake. But when a third object enters the picture, the problem becomes unsolvable. That's because when two massive objects get close to each other, their gravitational attraction influences the paths they take in a way...
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Gravitational waves—ripples in the fabric of Einstein's spacetime—that cross the universe at the speed of light have all sorts of wavelengths, or frequencies. Scientists have not yet managed to detect gravitational waves at extremely low 'nanohertz' frequencies, but new approaches currently being explored are expected to confirm the first low frequency signals quite soon. The main method uses radio telescopes to detect gravitational waves using pulsars—exotic, dead stars, that send out pulses of radio waves with extraordinary regularity. Researchers at the NANOGrav collaboration, for example, use pulsars to time to exquisite precision the rotation periods of a network, or array,...
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The five-decade-old paradox — long thought key to linking quantum theory with Einstein’s theory of gravity — is falling to a new generation of thinkers. Netta Engelhardt is leading the way. =============================================================================== In 1974, Stephen Hawking calculated that black holes’ secrets die with them. Random quantum jitter on the spherical outer boundary, or “event horizon,” of a black hole will cause the hole to radiate particles and slowly shrink to nothing. Any record of the star whose violent contraction formed the black hole — and whatever else got swallowed up after — then seemed to be permanently lost. Hawking’s calculation...
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Summertime means it’s time to play ball! But what would it be like to play ball on various locations across our Solar System? Planetary scientist Dr. James O’Donoghue has put together a fun animation of how quickly an object falls on to the surfaces of places like the Sun, Earth, Ceres, Jupiter, the Moon, and Pluto. The animation shows a ball dropping from 1 kilometer to the surface of each object, assuming no air resistance. You can compare, for example, that it takes 2.7 seconds for a ball to drop that distance on the Sun, while it takes 14.3 seconds...
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https://www.youtube.com/watch?v=9aVrly1bSq0
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Polarized view of the black hole in M87. The lines mark the orientation of polarization, which is related to the magnetic field around the shadow of the black hole. Credit: EHT Collaboration ===================================================================== Wits University astrophysicists are the only two scientists on African continent that contributed to the study. The Event Horizon Telescope (EHT) collaboration, a multinational team of over 300 scientists including two astrophysicists from the University of the Witwatersrand (Wits University), has revealed a new view of the massive object at the center of the M87 galaxy: how it looks in polarized light. This is the first time...
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