Archive for the ‘physics’ category: Page 123

Apr 23, 2020

Cosmic beasts collision sings a loud gravitational wave hum

Posted by in categories: cosmology, physics

The collision of two black holes produced a gravitational wave signal unlike any other heard before.

Apr 19, 2020

Gravitational waves reveal unprecedented collision of heavy and light black holes

Posted by in categories: cosmology, physics

Researchers with the world’s gravitational wave detectors said today they had picked up vibrations from a cosmic collision that harmonized with the opening notes of an Elvis Presley hit. The source was the most exotic merger of two black holes detected yet—a pair in which one weighed more than three times as much as the other. Because of the stark mass imbalance, the collision generated gravitational waves at multiple frequencies, in a harmony Elvis fans would recognize. The chord also confirms a prediction of Einstein’s theory of gravity, or general relativity.

Such mismatched mass events could help theorists figure out how pairs of black holes form in the first place. “Anything that seems to be at the edge of our predictions is most interesting,” says Chris Belczynski, a gravitational theorist at the Polish Academy of Sciences in Warsaw, who was not involved in the observation. But the one event is “not quite in the regime where you can tell the different formation [routes] apart.”

Physicists first detected gravitational waves in 2015, when the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of detectors in Washington and Louisiana, spotted two black holes spiraling into each other, generating infinitesimal ripples in spacetime. Two years later, the Virgo detector near Pisa, Italy, joined the hunt, and by August 2017, the detectors had bagged a total of 10 black hole mergers.

Apr 18, 2020

Achieving the Impossible: Physicists Create a Fluid with NEGATIVE MASS

Posted by in category: physics

In an act that defies physics as we know, Washington State University physicists have just created a fluid with negative mass. Apply pressure to the liquid and instead of accelerating in the direction it was pushed (like every other physical object in the world), it accelerates backward. Michael Forbes, a WSU assistant professor of physics and astronomy, believes the phenomenon can be used to explore some of the more challenging concepts of the cosmos.

“Hypothetically, matter can have negative mass in the same sense that an electric charge can be either negative or positive,” the University’s website notes. “People rarely think in these terms, and our everyday world sees only the positive aspects of Isaac Newton’s Second Law of Motion, in which the force is equal to the mass of an object times its acceleration, or F=ma.”

This explains why mass will typically accelerate in the direction of the force that is pushing it.

Apr 17, 2020

Olive oil leads to discovery of new universal law of phase transitions

Posted by in category: physics

A simple drop of olive oil in a system of photons bouncing between two mirrors has revealed universal aspects of phase transitions in physics. Researchers at AMOLF used an oil-filled optical cavity in which light undergoes phase transitions similar to those in boiling water. The system they studied has memory because the oil causes photons to interact with themselves. By varying the distance between the two mirrors and measuring the transmission of light through the cavity, they discovered a universal law describing phase transitions in systems with memory. These results are published on April 15th in Physical Review Letters.

The Interacting Photons research group at AMOLF studies nonlinearity and noise in photonic systems. One of such systems is a , formed by two mirrors facing each other at a close distance. Within the cavity, light bounces back and forth as it is reflected by the mirrors. Putting something inside such an , changes the properties of the system. “We created a system with by placing a drop of inside the cavity,” says group leader Said Rodriguez. “The oil mediates effective photon-photon interactions, which we can see by measuring the transmission of laser light through this cavity.”

Apr 14, 2020

Finally We May Have a Path to the Fundamental Theory of Physics… and It’s Beautiful—Stephen Wolfram Writings

Posted by in category: physics

I think Wolfram has found the right path forward.

Apr 14, 2020

Stephen Wolfram Invites You to Solve Physics

Posted by in category: physics

The Wolfram Physics Project intends to crowdsource the pursuit of the discipline’s holy grail: A fundamental theory of everything.

Apr 14, 2020

Stephen Wolfram’s proposal aims for a fundamental theory of physics

Posted by in categories: physics, space

Simple rules generating complicated networks may be how to build the universe.

Contributing Correspondent

Apr 14, 2020

‘Nuclear Pasta’ Inside Neutron Stars Is Strongest Material in Universe

Posted by in categories: cosmology, physics

A neutron star is the dead husk of a star more massive than the sun, but not large enough to become a black hole upon its demise. These stars are between 10 and 29 solar masses during their active lifetime. When they exhaust their nuclear fuel and go supernova, all that’s left is the ultra-dense collapsed core. We call that a neutron star.

The wild physics inside a neutron star are down to the incredible mass packed into such a small space. A neutron star might have twice the mass of our sun packed into an object just a few miles across. The crush of gravity contorts and squeezes neutrons into unusual configurations, based on the models developed by scientists studying neutron stars.

Scientists currently believe that neutron stars have layers characterized by different configurations of distorted neutron matter. For whatever reason, researchers have decided to name the various structures after pasta. Near the surface there’s gnocchi, which are round bubble-like neutrons. Go a bit deeper, and the pressure forces neutrons into long tubes called spaghetti. Go further down, and you have sheets of neutrons called lasagna. That’s just the start of the Italian-inspired interior of neutron stars.

Apr 8, 2020

A Mathematician Has Proposed a Way to Create And Manipulate Gravity

Posted by in categories: physics, space

Yesterday, the physics community got hyped-up over rumours that scientists might have finally detected gravitational waves — ripples in the curvature of spacetime predicted by Einstein 100 years ago — and that their observations could be coming to a peer-reviewed journal near you soon.

So far, our understanding of how gravity affects the Universe has been limited to observations of natural gravitational fields created by distant stars and planets. In fact, gravity is the last of the four fundamental forces that humans haven’t figured out how to produce and control. But now André Füzfa, a mathematician at the University of Namur in Belgium, has published a paper proposing a device that could do just that — albeit in tiny doses. And it wouldn’t require any new technology.

Let’s be clear, we’re talking about incredibly small gravitational fields here, not the type of ‘artificial gravity’ that’s used throughout science fiction to keep characters on shows like Star Trek and Battlestar Galactica walking, not floating, around spacecraft. As yet, that technology isn’t possible.

Apr 8, 2020

Universe expansion may not be uniform

Posted by in categories: cosmology, physics

(8 April 2020 — ESA) Astronomers have assumed for decades that the Universe is expanding at the same rate in all directions. A new study based on data from ESA’s XMM-Newton, NASA’s Chandra and the German-led ROSAT X-ray observatories suggests this key premise of cosmology might be wrong.

Konstantinos Migkas, a PhD researcher in astronomy and astrophysics at the University of Bonn, Germany, and his supervisor Thomas Reiprich originally set out to verify a new method that would enable astronomers to test the so-called isotropy hypothesis. According to this assumption, the Universe has, despite some local differences, the same properties in each direction on the large scale.

Widely accepted as a consequence of well-established fundamental physics, the hypothesis has been supported by observations of the cosmic microwave background (CMB). A direct remnant of the Big Bang, the CMB reflects the state of the Universe as it was in its infancy, at only 380 000 years of age. The CMB’s uniform distribution in the sky suggests that in those early days the Universe must have been expanding rapidly and at the same rate in all directions.