Lifeboat Foundation

A light in the dark — If quantum computers continue to advance, and perform more calculations for less steep costs, Rinaldi and his team might be able to reveal what happens inside of black holes, beyond the event horizon — a region immediately surrounding a black hole’s singularity, within which not even light, nor perhaps time itself, can escape the immense force of gravity.

In practical terms, the event horizon prevents all conventional, light-based observations. But, and perhaps more compelling, the team hopes that further advances in this line of inquiry will do more than peek inside a black hole, and unlock what physicists have dreamed of since the days of Einstein: a unified theory of physics.

Circa 2020

It was an old idea of Stephen Hawking’s: Unseen “primordial” black holes might be the hidden dark matter. A new series of studies has shown how the theory can work.

The thing is, it could be—and a University of Michigan physicist is using quantum computing and machine learning to better understand the idea, called holographic duality.

A study by the University of Bonn: Observations fit poorly with the Standard Model of Cosmology.

The Standard Model of Cosmology describes how the universe came into being according to the view of most physicists. Researchers at the University of Bonn have now studied the evolution of galaxies within this model, finding considerable discrepancies with actual observations. The University of St. Andrews in Scotland and Charles University in the Czech Republic were also involved in the study. The results have now been published in the Astrophysical Journal.

Most galaxies visible from Earth resemble a flat disk with a thickened center. They are therefore similar to the sports equipment of a discus thrower. According to the Standard Model of Cosmology, however, such disks should form rather rarely. This is because in the model, every galaxy is surrounded by a halo of dark matter. This halo is invisible, but exerts a strong gravitational pull on nearby galaxies due to its mass. “That’s why we keep seeing galaxies merging with each other in the model universe,” explains Prof. Dr. Pavel Kroupa of the Helmholtz Institute for Radiation and Nuclear Physics at the University of Bonn.

It’s hard to spot a black hole.

There are two different approaches to such detection. In “X-ray binary stars” — in which a star and a black hole orbit a shared center while producing X-rays — a black hole’s gravitational field can pull material from its companion. The material circles the black hole, heating up by friction as it does so.

The hot material glows brightly in X-ray light, making the black hole visible, before being sucked into the black hole and disappearing. You can also detect pairs of black holes as they merge together, spiraling inwards and emitting a brief flash of gravitational waves, which are ripples in spacetime.

Continue reading “Scientists may have just found an invisible black hole — should you be worried?” »

Astronomers found that parts of the galaxy where stars are born were being protected from these powerful outflows thanks to its structure.

The nature of dark matter continues to perplex astronomers. As the search for dark matter particles continues to turn up nothing, it’s tempting to throw out the dark matter model altogether, but indirect evidence for the stuff continues to be strong. So what is it? One team has an idea, and they’ve published the results of their first search.

The conditions of dark matter mean that it can’t be regular matter. Regular matter (atoms, molecules, and the like) easily absorbs and emits light. Even if dark matter were clouds of molecules so cold they emitted almost no light, they would still be visible by the light they absorb. They would appear like dark nebula commonly seen near the galactic plane. But there aren’t nearly enough of them to account for the effects of dark matter we observe. We’ve also ruled out neutrinos. They don’t interact strongly with light, but neutrinos are a form of “hot” dark matter since neutrinos move at nearly the speed of light. We know that most dark matter must be sluggish, and therefore “cold.” So if dark matter is out there, it must be something else.

In this latest work, the authors argue that dark matter could be made of particles known as scalar bosons. All known matter can be placed in two large categories known as fermions and bosons. Which category a particle is in depends on a quantum property known as spin. Fermions such as electrons and quarks have fractional spin such as 1/2 or 3/2. Bosons such as photons have an integer spin such as 1 or 0. Any particle with a spin of 0 is a scalar boson.