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...

Sperm Breaks Law of Motion

The laws of physics have been broken (or appear to have been broken) by all manner of things, from balancing rocks to Seinfeld’s apartment, and now, by human sperm. The latest law-breakers defy Newton's third law of motion, distorting their bodies as they swim in a way that elicits no response from their surroundings.

Newton's third law states that when one object exerts a force on a second object, the second object exerts an equal and opposite force back. In other words, “for every action, there is an equal and opposite reaction”. However, for biological swimmers such as sperm, this may not be the case.  READ MORE...

Physics Mystery Solved

Technion researchers have found an effective solution to the famous age-old, three-body problem in physics.

The three-body problem is one of the oldest problems in physics: it concerns the motions of systems of three bodies – like the Sun, Earth, and the Moon – and how their orbits change and evolve due to their mutual gravity. The three-body problem has been a focus of scientific inquiry ever since Newton.

When one massive object comes close to another, their relative motion follows a trajectory dictated by their mutual gravitational attraction, but as they move along, and change their positions along their trajectories, the forces between them, which depend on their mutual positions, also change, which, in turn, affects their trajectory et cetera. For two bodies (e.g. like Earth moving around the Sun without the influence of other bodies), the orbit of the Earth would continue to follow a very specific curve, which can be accurately described mathematically (an ellipse).

However, once one adds another object, the complex interactions lead to the three-body problem, namely, the system becomes chaotic and unpredictable, and one cannot simply specify the system evolution over long time-scales. Indeed, while this phenomenon has been known for over 400 years, ever since Newton and Kepler, a neat mathematical description for the three-body problem is still lacking.

Star orbits in a three-body system. Credit: Technion

In the past, physicists – including Newton himself – have tried to solve this so-called three-body problem; in 1889, King Oscar II of Sweden even offered a prize, in commemoration of his 60th birthday, to anybody who could provide a general solution. In the end, it was the French mathematician Henri Poincaré who won the competition. He ruined any hope for a full solution by proving that such interactions are chaotic, in the sense that the final outcome is essentially random; in fact, his finding opened a new scientific field of research, termed chaos theory.  READ MORE...

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...

Swirlons

Meet the swirlon, a new kind of matter that bends the laws of physics
By Stephanie Pappas - Live Science Contributor 5 days ago

Researchers discover a...

Physical laws such as Newton's second law of motion — which states that as a force applied to an object increases, its acceleration increases, and that as the object's mass increases, its acceleration decreases — apply to passive, nonliving matter, ranging from atoms to planets. But much of the matter in the world is active matter and moves under its own, self-directed, force, said Nikolai Brilliantov, a mathematician at Skolkovo Institute of Science and Technology in Russia and the University of Leicester in England. Living things as diverse as bacteria, birds and humans can interact with the forces upon them. There are examples of non-living active matter, too. Nanoparticles known as "Janus particles," are made up of two sides with different chemical properties. The interactions between the two sides create self-propelled movement.

To explore active matter, Brilliantov and his colleagues used a computer to simulate particles that could self-propel. These particles weren't consciously interacting with the environment, Brilliantov told Live Science. Rather, they were more akin to simple bacteria or nanoparticles with internal sources of energy, but without information-processing abilities.  TO READ ENTIRE ARTICLE, Click Here...