Lifeboat Foundation

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 cavity, 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 optical cavity, changes the properties of the system. “We created a system with memory by placing a drop of olive oil 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.”

I think Wolfram has found the right path forward.

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

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

Contributing Correspondent

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.

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.

(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.

The laws of physics imply that the passage of time is an illusion. To avoid this conclusion, we might have to rethink the reality of infinitely precise numbers.

Astronomers have detected two stellar corpses whirling around each other, and they might be producing gravitational waves.

White dwarf stars are what become of stars like our sun after they run out of fuel and turn into leftover hot cores. For many years, researchers have predicted that there should be binary, or two-object, systems made up of white dwarf stars. According to general relativity, two such masses orbiting each other should emit energy in the form of gravitational waves, which are ripples or disturbances in the fabric of spacetime.