Showing posts with label General Relativity. Show all posts
Showing posts with label General Relativity. Show all posts
Thursday, December 5
A Quirk in SPACE-TIME
Gravitational lensing of galaxy cluster Abell 2390. (ESA/Euclid/Euclid Consortium/NASA, image processing by J.-C. Cuillandre (CEA Paris-Saclay), G. Anselmi)
The fabric of space and time is not exempt from the effects of gravity. Plop in a mass and space-time curves around it, not dissimilar to what happens when you put a bowling ball on a trampoline.
This dimple in space-time is the result of what we call a gravity well, and it was first described over 100 years ago by Albert Einstein's field equations in his theory of general relativity. To this day, those equations have held up. We'd love to know what Einstein was putting in his soup. Whatever it was, general relativity has remained pretty solid.
One of the ways we know this is because when light travels along that curved space-time, it curves along with it. This results in light that reaches us all warped and stretched and replicated and magnified, a phenomenon known as gravitational lensing. This quirk of space-time is not only observable and measurable, it's an excellent tool for understanding the Universe. READ MORE...
Monday, August 5
Quantum Mechanics United with General Relativity
Scientists have revealed a radical theory that seeks to reconcile two pillars of modern physics – quantum mechanics and Einstein’s theory of general relativity. (CREDIT: Isaac Young)
In a cutting-edge development that has sent shockwaves through the scientific community, researchers at University College London (UCL) have unveiled a radical theory that seeks to reconcile two pillars of modern physics – quantum mechanics and Einstein's general theory of relativity.
These two theories, which have been the foundation of physics for over a century, have long been at odds with each other, and their unification has remained an elusive quest.
Today, we dive into the world of quantum gravity, a field of study that aims to bridge the gap between the quantum realm, which governs the behavior of particles at the smallest scales, and the macroscopic world, where gravity shapes the very fabric of spacetime.
While the prevailing consensus has been that Einstein's theory of gravity must be modified to fit within the framework of quantum theory, a new theory, coined as a "postquantum theory of classical gravity," challenges this assumption in a thought-provoking way. READ MORE...
These two theories, which have been the foundation of physics for over a century, have long been at odds with each other, and their unification has remained an elusive quest.
Today, we dive into the world of quantum gravity, a field of study that aims to bridge the gap between the quantum realm, which governs the behavior of particles at the smallest scales, and the macroscopic world, where gravity shapes the very fabric of spacetime.
While the prevailing consensus has been that Einstein's theory of gravity must be modified to fit within the framework of quantum theory, a new theory, coined as a "postquantum theory of classical gravity," challenges this assumption in a thought-provoking way. READ MORE...
Saturday, May 11
A Glitch in Einstein's Theory
This James Webb Space Telescope deep-field image shows some of the earliest and most distant galaxies ever seen. (Image credit: NASA, ESA, CSA and STScI)
There is no denying the awesome predictive power of Albert Einstein's 1915 theory of gravity, general relativity — yet, the theory still has inconsistencies when it comes to calculating its effect on vast distances. And new research suggests these inconsistencies could be the result of a "cosmic glitch" in gravity itself.
In the 109 years since it was first formulated, general relativity has remained our finest description of gravity on a galactic scale; time and again, experiments have confirmed its accuracy. This theory has also been used to predict aspects of the universe that would later be observationally confirmed. This includes the Big Bang, the existence of black holes, the gravitational lensing of light and tiny ripples in spacetime called gravitational waves.
Yet, like the Newtonian theory of gravity that it surpassed, general relativity may not offer us the full picture of this enigmatic force. READ MORE...
Sunday, October 1
Einstein Was Wrong About Gravity
Einstein's theory of gravity—general relativity—has been very successful for more than a century. However, it has theoretical shortcomings. This is not surprising: the theory predicts its own failure at spacetime singularities inside black holes—and the Big Bang itself.
Unlike physical theories describing the other three fundamental forces in physics—the electromagnetic and the strong and weak nuclear interactions—the general theory of relativity has only been tested in weak gravity.
Deviations of gravity from general relativity are by no means excluded nor tested everywhere in the universe. And, according to theoretical physicists, deviation must happen.
Deviations and quantum mechanics
According to a theory initially proposed by Georges Lemaître and widely accepted by the astronomical community, our universe originated in a Big Bang.
Other singularities hide inside black holes: Space and time cease to have meaning there, while quantities such as energy density and pressure become infinite. These signal that Einstein's theory is failing there and must be replaced with a more fundamental one.
Naively, spacetime singularities should be resolved by quantum mechanics, which apply at very small scales.
Quantum physics relies on two simple ideas: point particles make no sense; and the Heisenberg uncertainty principle, which states that one can never know the value of certain pairs of quantities with absolute precision—for example, the position and velocity of a particle.
Naively, spacetime singularities should be resolved by quantum mechanics, which apply at very small scales.
Quantum physics relies on two simple ideas: point particles make no sense; and the Heisenberg uncertainty principle, which states that one can never know the value of certain pairs of quantities with absolute precision—for example, the position and velocity of a particle.
This is because particles should not be thought of as points but as waves; at small scales they behave as waves of matter. READ MORE...
Friday, July 7
Space-Time Distortions
Observing time distortions could show whether Einstein's theory of general relativity accounts for the mysteries of dark matter and dark energy.
Scientists could soon test Einstein's theory of general relativity by measuring the distortion of time.
According to new research published June 22 in the journal Nature Astronomy, the newly proposed method turns the edge of space and time into a vast cosmic lab to investigate if general relativity can account for dark matter - a mysterious, invisible form of matter that can only be inferred by its gravitational influence on the universe's visible matter and energy - as well as the accelerating expansion of the universe due to dark energy. The method is ready to be tested on future surveys of the deep universe, according to the study authors.
General relativity states that gravity is the result of mass warping the fabric of space and time, which Einstein lumped into a four-dimensional entity called space-time. According to relativity, time passes more slowly close to a massive object than it does in a mass-less vacuum. This change in the passing of time is called time distortion.
Since its introduction in 1915, general relativity has been tested extensively and has become our best description of gravity on tremendous scales. But scientists aren't yet sure if it can explain invisible dark matter and dark energy, which together account for around 95% of the energy and matter in the universe. READ MORE...
Tuesday, May 3
Time Does Not Exist (?)
Does time exist? The answer to this question may seem obvious: Of course it does! Just look at a calendar or a clock.
But developments in physics suggest the non-existence of time is an open possibility, and one that we should take seriously.
How can that be, and what would it mean? It'll take a little while to explain, but don't worry: Even if time doesn't exist, our lives will go on as usual.
A crisis in physics
Physics is in crisis. For the past century or so, we have explained the Universe with two wildly successful physical theories: general relativity and quantum mechanics.
Quantum mechanics describes how things work in the incredibly tiny world of particles and particle interactions. General relativity describes the big picture of gravity and how objects move.
Both theories work extremely well in their own right, but the two are thought to conflict with one another. Though the exact nature of the conflict is controversial, scientists generally agree both theories need to be replaced with a new, more general theory.
Physicists want to produce a theory of "quantum gravity" that replaces general relativity and quantum mechanics, while capturing the extraordinary success of both. Such a theory would explain how gravity's big picture works at the miniature scale of particles.
Time in quantum gravity
It turns out that producing a theory of quantum gravity is extraordinarily difficult.
One attempt to overcome the conflict between the two theories is string theory. String theory replaces particles with strings vibrating in as many as 11 dimensions. READ MORE...
It turns out that producing a theory of quantum gravity is extraordinarily difficult.
One attempt to overcome the conflict between the two theories is string theory. String theory replaces particles with strings vibrating in as many as 11 dimensions. READ MORE...
Saturday, April 30
One Way Time Travel
Have you ever made a mistake that you wish you could undo? Correcting past mistakes is one of the reasons we find the concept of time travel so fascinating. As often portrayed in science fiction, with a time machine, nothing is permanent anymore – you can always go back and change it. But is time travel really possible in our universe, or is it just science fiction?
Our modern understanding of time and causality comes from general relativity. Theoretical physicist Albert Einstein's theory combines space and time into a single entity – "spacetime" – and provides a remarkably intricate explanation of how they both work, at a level unmatched by any other established theory.
This theory has existed for more than 100 years, and has been experimentally verified to extremely high precision, so physicists are fairly certain it provides an accurate description of the causal structure of our Universe.
For decades, physicists have been trying to use general relativity to figure out if time travel is possible. It turns out that you can write down equations that describe time travel and are fully compatible and consistent with relativity. But physics is not mathematics, and equations are meaningless if they do not correspond to anything in reality. READ MORE...
Sunday, August 8
Backside of Black Hole
Scientists have finally seen the backside of a black hole and in doing so, they've proved that a 1915 theory posited by Albert Einstein was correct.
Einstein's 1915 Theory of General Relativity predicted that the gravitational pull of black holes is so large that black holes warp the fabric of space, according to The Telegraph.
Einstein's 1915 Theory of General Relativity predicted that the gravitational pull of black holes is so large that black holes warp the fabric of space, according to The Telegraph.
His theory posited that this extremely massive gravitational pull was so massive that it twists magnetic fields and bends lightwaves near black holes.
As reported by The Telegraph, a new Nature report proves Einstein's theory correct.
"Fifty years ago, when astrophysicists started speculating about how the magnetic field might behave close to a black hole, they had no idea that one day we might have the techniques to observe this directly and see Einstein's general theory of relativity in action," Standford University professor and research report co-author, Roger Blandford, said.
Einstein's theory stated that because of how black holes warp the space fabric around them, it should be possible to see light waves ejected out of a black hole's backside as the twisted magnetic fields act as a mirror for the black hole.
As reported by The Telegraph, a new Nature report proves Einstein's theory correct.
"Fifty years ago, when astrophysicists started speculating about how the magnetic field might behave close to a black hole, they had no idea that one day we might have the techniques to observe this directly and see Einstein's general theory of relativity in action," Standford University professor and research report co-author, Roger Blandford, said.
Einstein's theory stated that because of how black holes warp the space fabric around them, it should be possible to see light waves ejected out of a black hole's backside as the twisted magnetic fields act as a mirror for the black hole.
This theory was accepted by experts, according to The Telegraph, but it was never technically proven as it was always deemed an unobservable phenomenon. READ MORE
Monday, June 28
Einstein is Wrong...
General relativity is wrong. GR is not based on nature’s foundation of Euclidean space and time permeated by energy carrying immutable point charges.
We can rehabilitate GR with the concept of Quantum General Relativity which has the following corrections :
- QGR is rebased into Euclidean space and time.
- QGR is based on geometrical, physically immutable, quanta of charge.
- In the context of QGR, the quantum is redefined and reframed as the electrino and positrino point charges (at -e/6 and +e/6 respectively).
- QGR deals properly with the fixed high energy limit per charge quantum and the associated density limits and electromagnetic configuration.
- QGR is enhanced with the understanding that Euclidean space is permeated by structures that have characteristics that vary with their energy, as well as the energy of local structures, tapering with distance. These physical characteristics implement Einstein’s spacetime geometry.
- QGR includes mathematical bridges between Euclidean coordinates in space and time and Riemannian coordinates in spacetime aether.
What is the mechanism?
Do their energy cores leak energy or pay a toll?
Dense standard matter such as is found in a planet or star or galaxy energizes the spacetime aether in and around them. The aether is rather passive — it is mostly doing the Einstein stretchy-curvy behaviour, so in some cases the energized aether is left behind as a wake. Astrophysicists call it dark matter. TO READ MORE, CLICK HERE...
Saturday, May 29
Gravitational Waves
As in history, revolutions are the lifeblood of science. Bubbling undercurrents of disquiet boil over until a new regime emerges to seize power. Then everyone's attention turns to toppling their new ruler. The king is dead, long live the king.
This has happened many times in the history of physics and astronomy. First, we thought Earth was at the center of the solar system — an idea that stood for over 1,000 years. Then Copernicus stuck his neck out to say that the whole system would be a lot simpler if we are just another planet orbiting the sun. Despite much initial opposition, the old geocentric picture eventually buckled under the weight of evidence from the newly invented telescope.
Then Newton came along to explain that gravity is why the planets orbit the sun. He said all objects with mass have a gravitational attraction towards each other. According to his ideas we orbit the sun because it is pulling on us, the moon orbits Earth because we are pulling on it. Newton ruled for two-and-a-half centuries before Albert Einstein turned up in 1915 to usurp him with his General Theory of Relativity. This new picture neatly explained inconsistencies in Mercury's orbit, and was famously confirmed by observations of a solar eclipse off the coast of Africa in 1919.
Instead of a pull, Einstein saw gravity as the result of curved space. He said that all objects in the universe sit in a smooth, four-dimensional fabric called space-time. Massive objects such as the sun warp the space-time around them, and so Earth's orbit is simply the result of our planet following this curvature. To us that looks like a Newtonian gravitational pull. This space-time picture has now been on the throne for over 100 years, and has so far vanquished all pretenders to its crown. The discovery of gravitational waves in 2015 was a decisive victory, but, like its predecessors, it too might be about to fall. That's because it is fundamentally incompatible with the other big beast in the physics zoo: Quantum theory.
The quantum world is notoriously weird. Single particles can be in two places at once, for example. Only by making an observation do we force it to 'choose'. Before an observation we can only assign probabilities to the likely outcomes. In the 1930s, Erwin Schrödinger devised a famous way to expose how perverse this idea is. He imagined a cat in a sealed box accompanied by a vial of poison attached to a hammer. The hammer is hooked up to a device that measures the quantum state of a particle. Whether or not the hammer smashes the vial and kills the cat hinges on that measurement, but quantum physics says that until such a measurement is made, the particle is simultaneously in both states, which means the vial is both broken and unbroken and the cat is alive and dead. TO READ MORE, CLICK HERE...
This has happened many times in the history of physics and astronomy. First, we thought Earth was at the center of the solar system — an idea that stood for over 1,000 years. Then Copernicus stuck his neck out to say that the whole system would be a lot simpler if we are just another planet orbiting the sun. Despite much initial opposition, the old geocentric picture eventually buckled under the weight of evidence from the newly invented telescope.
Then Newton came along to explain that gravity is why the planets orbit the sun. He said all objects with mass have a gravitational attraction towards each other. According to his ideas we orbit the sun because it is pulling on us, the moon orbits Earth because we are pulling on it. Newton ruled for two-and-a-half centuries before Albert Einstein turned up in 1915 to usurp him with his General Theory of Relativity. This new picture neatly explained inconsistencies in Mercury's orbit, and was famously confirmed by observations of a solar eclipse off the coast of Africa in 1919.
Instead of a pull, Einstein saw gravity as the result of curved space. He said that all objects in the universe sit in a smooth, four-dimensional fabric called space-time. Massive objects such as the sun warp the space-time around them, and so Earth's orbit is simply the result of our planet following this curvature. To us that looks like a Newtonian gravitational pull. This space-time picture has now been on the throne for over 100 years, and has so far vanquished all pretenders to its crown. The discovery of gravitational waves in 2015 was a decisive victory, but, like its predecessors, it too might be about to fall. That's because it is fundamentally incompatible with the other big beast in the physics zoo: Quantum theory.
The quantum world is notoriously weird. Single particles can be in two places at once, for example. Only by making an observation do we force it to 'choose'. Before an observation we can only assign probabilities to the likely outcomes. In the 1930s, Erwin Schrödinger devised a famous way to expose how perverse this idea is. He imagined a cat in a sealed box accompanied by a vial of poison attached to a hammer. The hammer is hooked up to a device that measures the quantum state of a particle. Whether or not the hammer smashes the vial and kills the cat hinges on that measurement, but quantum physics says that until such a measurement is made, the particle is simultaneously in both states, which means the vial is both broken and unbroken and the cat is alive and dead. TO READ MORE, CLICK HERE...
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