Articles tagged with General Relativity
Sir Roger Penrose's 1965 theorem associates black holes with trapped surfaces that shrink over time. The theory also predicts the existence of singularities in extreme conditions, highlighting the limitations of Einstein's General Theory of Relativity.
Researchers at UC Berkeley conducted an experiment to detect dark energy particles called 'chameleons,' which were proposed as a possible explanation for the mysterious energy. The results narrowed the search by a thousand times compared to previous tests, ruling out certain energies and eliminating a large range of possible particles.
Theoretical physicists explore effects of breaking Lorentz invariance in ultraviolet region to create renormalizable theories. A holographic superconductor can still be realized in this new gravity without LI.
Researchers have discovered that time dilation caused by gravity can explain the suppression of quantum behavior in larger objects, such as molecules and dust particles. This effect destroys quantum superposition and forces these objects to behave classically.
A team from Imperial College London and University of Barcelona used astronomical surveys to measure the baryon acoustic oscillation scale, a standard distance central to the universe's expansion. The study suggests current methods for measuring distance are more complicated than needed, offering a data-driven approach to cosmology.
Researchers from Spain and India found that pulsars with black holes are ideal for testing general relativity, but two cases reduce their value. The 'holy grail' pair is a normal black hole, which has yet to be discovered.
Researchers found weak gravitational lensing in CMB polarization data, allowing detailed maps of the universe and constraining neutrino mass estimates. The discovery provides a firm test for general relativity on cosmological scales.
A 1931 paper by Albert Einstein featuring a dynamic model of the universe has been re-examined, highlighting numerical errors and questionable calculations. The model, which includes a contraction phase, contrasts with the widely known expanding Einstein-de Sitter model.
In 1917 Einstein applied general relativity to a static universe, introducing the cosmological constant to address gravitational collapse. He resisted expanding universe views despite contemporary suggestions from astrophysicists Alexander Friedman and Georges Lemaître.
Astronomers have discovered a 3-star system that challenges the strong equivalence principle in Albert Einstein's theory of General Relativity. The system, consisting of two white dwarf stars and a superdense pulsar, allows for precise timing observations to test the theory's validity.
Astrophysicists used supercomputer simulations and traditional calculations to demonstrate that gas spiraling toward a black hole inevitably results in X-ray emissions. The study reveals high-energy light emission is not only possible but also an inevitable outcome of gas being drawn into a black hole.
Researchers developed large ring laser gyroscopes six orders of magnitude more sensitive than commercial instruments. These devices can measure the Earth's rotation rate with unprecedented accuracy, capturing momentum exchange between atmosphere, hydrosphere, and lithosphere.
Astronomers have measured the spin rate of a supermassive black hole, providing insights into the galaxy's evolution. The black hole's spin is linked to its accretion disk and can offer clues about the galaxy's past.
Astronomers report the discovery of S0-102, a star with an extremely short orbit near the supermassive black hole at the Milky Way's galactic center. The study aims to test Einstein's theory of general relativity and reveal the fabric of space and time around a black hole.
Researchers have discovered a star orbiting the Milky Way's monster black hole in just 11.5 years, offering a new test of Einstein's general theory of relativity. TMT will enable breakthroughs on astrometric precision and potentially find even more tightly bound stars, allowing for tests of gravity's warping of space-time.
Astronomers have measured the closest distance that matter can approach a black hole without being pulled in. The findings suggest that the accretion disk is spinning in the same direction as the black hole, providing new insights into gravity and space.
The South Pole Telescope's data analysis provides strong support for the cosmological constant as the source of dark energy, accelerating the universe's expansion. The results also place tight limits on neutrino masses, shedding light on these mysterious particles' properties.
Researchers at the University of Vienna aim to measure general relativistic time on a quantum scale by exploiting quantum interference and complementarity. They consider a single clock in a superposition of two locations, one closer and one further away from Earth, where gravity's effects are different.
Researchers at UCSB successfully reproduced the Josephson junction using Einstein's general theory of relativity, a breakthrough that sheds new light on non-gravitational physics. The discovery has significant implications for understanding superconductivity and the development of room-temperature superconductors.
Physicist Adilson E. Motter and colleague Katrin Gelfert show that chaos is absolute in the universe's early expansion, disagreeing with previous studies' relative views. The study implies that the early universe experienced erratic changes between red- and blue-shift directions, confirming chaotic behavior.
Astronomers have discovered a quasar that acts as a gravitational lens, allowing them to weigh and measure a distant galaxy containing a black hole. This groundbreaking observation was made possible by the Sloan Digital Sky Survey database and will provide new insights into the distribution of matter in the universe.
A team of Princeton University scientists tested Albert Einstein's theory of general relativity at cosmic scales, concluding it works as well in vast distances as in local regions. They analyzed over 70,000 galaxies and demonstrated that the universe follows Einstein's rules up to 3.5 billion light years from Earth.
A team of researchers has analyzed over 70,000 galaxies to test two modified gravity theories that aim to explain dark matter's effects on the universe. The study found that one theory, TeVeS, can be excluded due to large uncertainty in measurements, while another theory, f(R), still allows for exclusion of dark energy with current data.
Researchers used VLBA system to measure bending of starlight by gravity, achieving precision of one part in 30,000. The accurate measurement brings scientists closer to uniting General Relativity and quantum theory.
Researchers propose new way to detect anomalies in fundamental physics principle, potentially revealing space-time variations and relativity violations. This discovery could have significant implications for understanding gravity and particle behavior.
The new field of transformation optics harnesses nanotechnology and metamaterials to manipulate and control light at all scales. Researchers envision applications such as electromagnetic cloaks, ultra-powerful microscopes, and faster computers that use light instead of electronic signals.
Researchers at Penn State have discovered a mechanism that allows information to be recovered from black holes, contrary to Stephen Hawking's previous assertion. By expanding space-time beyond its assumed size, the team finds room for information to reappear in the distant future.
Researchers using Loop Quantum Gravity theory find a contracting universe before the Big Bounce, with space-time geometry similar to today's. A new mathematical model allows for precise analytical solutions and reveals a 'cosmic forgetfulness' due to extreme quantum forces during the Big Bounce.
Researchers predict that braneworld black holes, created in the early universe, have survived and can be detected by observing gamma-ray bursts passing near them. The signature of these black holes could provide evidence for a fourth dimension of space.
A team of researchers at Penn State has discovered a mathematical description of a contracting universe that existed before the Big Bang, with space-time geometry and gravity exhibiting unique properties. The findings rely on loop quantum gravity theory, which proposes a discrete 'atomic' structure to space-time.
Researchers have successfully tested Einstein's relativity theory using ultra-thin Graphene, a material created by extracting graphite via pencil-tracing. This breakthrough enables direct experiments to test relativistic ideas, potentially leading to groundbreaking discoveries.
Cosmologists propose that the universe's acceleration can be explained by inflationary theory, which generates cosmic ripples that drive expansion. This solution relies on Einstein's General Relativity and doesn't require new ingredients like dark energy.
Fotini Markopoulo Kalamara presents a fresh approach to researching theoretical possibilities for looking inside black holes and at particles of space/time. She proposes that an 'inside' quantum theory of gravity should be the collection of all partial observations of the inside observers.
A team of scientists led by Indiana University's Alan Kostelecky aims to determine if Albert Einstein's theory of relativity holds true. By comparing extremely precise clocks in zero gravity, they may find changes that contradict the theory, revolutionizing our understanding of space and time.
University of Washington cosmologist Craig Hogan believes new experiments could shed light on subatomic particles called gravitons, potentially uniting quantum mechanics and relativity. These advancements might also provide clues to the holographic principle, which suggests everything in 3D can be specified by information in 2D.
John Moffat, a University of Toronto professor, proposes that the speed of light was not always constant but rather increased over time. This theory could help explain recent discoveries about the accelerating expansion of the universe and provide an answer to some cosmology problems.
Physicists Daniel Kabat and Gilad Lifschytz propose tachyons as the solution to explain how black holes absorb particles without violating M-theory. Tachyons, with imaginary mass, could provide a mechanism for energy absorption, making it possible for black holes to devour matter.
Astronomers believe the Universe has expanded since the big bang about 15 billion years ago, but a new theory proposes that it may have rotated like a merry-go-round for an indefinitely long period. If true, this rotation could have suddenly changed into expansion thanks to a 'vacuum phase transition.'
String theory proposes that elementary particles are vibrating strings in 10 dimensions, requiring a reconciliation of quantum mechanics and general relativity. Mathematicians have found Calabi-Yau manifolds that describe simple equations, which resemble special black holes in our four-dimensional world.
A study published in Science has re-examined the priority and plagiarism surrounding Einstein's General Relativity theory. The researchers argue that David Hilbert, not Einstein, was the first to submit the correct field equations of General Relativity, clearing Einstein of any wrongdoing.
Researchers calculate neutron star's mass by measuring X-ray pulses from innermost orbit, revealing a massive star about twice the sun's mass. The findings provide new insights into the birth and evolution of neutron stars.