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Physicists have proposed a new theory: in the first quintillionth of a second, the universe may have sprouted microscopic black holes with enormous amounts of nuclear charge.

For every kilogram of matter that we can see — from the computer on your desk to distant stars and galaxies — there are 5kgs of invisible matter that suffuse our surroundings. This “dark matter” is a mysterious entity that evades all forms of direct observation yet makes its presence felt through its invisible pull on visible objects.

Fifty years ago, physicist Stephen Hawking offered one idea for what dark matter might be: a population of black holes, which might have formed very soon after the Big Bang. Such “primordial” black holes would not have been the goliaths that we detect today, but rather microscopic regions of ultradense matter that would have formed in the first quintillionth of a second following the Big Bang and then collapsed and scattered across the cosmos, tugging on surrounding space-time in ways that could explain the dark matter that we know today.

A research team led by Academician Du Jiangfeng and Professor Rong Xing from the University of Science and Technology of China (USTC), part of the Chinese Academy of Sciences (CAS), in collaboration with Professor Jiao Man from Zhejiang University, has used solid-state spin quantum sensors to examine exotic spin-spin-velocity-dependent interactions (SSIVDs) at short force ranges. Their study reports new experimental findings concerning interactions between electron spins and has been published in Physical Review Letters.

The Standard Model is a very successful theoretical framework in particle physics, describing fundamental particles and four basic interactions. However, the Standard Model still cannot explain some important observational facts in current cosmology, such as dark matter and dark energy.

Some theories suggest that new particles can act as propagators, transmitting new interactions between Standard Model particles. At present, there is a lack of experimental research on new interactions related to velocity between spins, especially in the relatively small range of force distance, where experimental verification is almost non-existent.

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Researchers at UC Berkeley have enhanced the precision of gravity experiments using an atom interferometer combined with an optical lattice, significantly extending the time atoms can be held in free fall. Despite not yet finding deviations from Newton’s gravity, these advancements could potentially reveal new quantum aspects of gravity and test theories about exotic particles like chameleons or symmetrons.

Twenty-six years ago physicists discovered dark energy — a mysterious force pushing the universe apart at an ever-increasing rate. Ever since, scientists have been searching for a new and exotic particle causing the expansion.

Pushing the boundaries of this search, University of California, Berkeley physicists have now built the most precise experiment yet to look for minor deviations from the accepted theory of gravity that could be evidence for such a particle, which theorists have dubbed a chameleon or symmetron.

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What would Brian Greene do if he could travel through time, and which future technology is he most excited about?

After our full interview, I had the privilege to sit down with Brian and ask him a few more questions. Enjoy this exclusive Q\&A with one of the most renowned physicists of our time!

And if you haven’t already, check out our full interview: • Brian Greene: The Truth About String…

For decades, inflation has been the dominant cosmological scenario, but recently the theory has been subject to competition and critique. Two renowned pioneers of inflation — Alan Guth and Andrei Linde — join Brian Greene to make their strongest case for the inflationary theory.

This program is part of the Big Ideas series, supported by the John Templeton Foundation.

Participants:
Alan Guth.
Andrei Linde.

Moderator:

For the last seven decades, astrophysicists have theorized the existence of “kugelblitze,” black holes caused by extremely high concentrations of light.

These special black holes, they speculated, might be linked to astronomical phenomena such as , and have even been suggested as the power source of hypothetical spaceship engines in the far future.

However, new research by a team of researchers at the University of Waterloo and Universidad Complutense de Madrid demonstrates that kugelblitze are impossible in our current universe. Their research, titled “No black holes from ,” is published on the arXiv preprint server and is forthcoming in Physical Review Letters.

The universe is a massive place, with galaxies well beyond our own. However, some also hypothesize that there may be more than one universe. The multiverse theory essentially suggests that our universe is just one of many branching and infinite universes. These universes are believed to have appeared just after the Big Bang, and now, scientists may be closer than ever to proving this theory is correct.

The idea of a multiverse existing has gained a lot of following over the past several years—not only in entertainment avenues like the Marvel Cinematic Universe but also in the scientific community, especially since the 1980s when inflation—a period when the universe suddenly expanded—was invented. Inflation is the main explanation for why the universe is so smooth and flat. It also predicts the existence of several independent universes beyond our own.

But inflation isn’t the only route that scientists have looked at to prove the multiverse theory. Others have looked at alternatives called cyclic universes, which basically say the universe is on an unending cycle of ballooning and then compressing. It still focuses on that multiple universe prospect—though it focuses on them appearing at different times.

Note that this does not involve Planck mass fermionic black holes!


A population of massive black holes whose origin is one of the biggest mysteries in modern astronomy has been detected by the LIGO and Virgo gravitational wave detectors.

According to one hypothesis, these objects may have formed in the very early Universe and may compose dark matter, a mysterious substance filling the Universe. A team of scientists has announced the results of nearly 20-year-long observations indicating that such massive black holes may comprise at most a few percent of dark matter. Therefore, another explanation is needed for gravitational wave sources.

The results of the study were published in two articles, in Nature and the Astrophysical Journal Supplement Series. The research was conducted by scientists from the OGLE (Optical Gravitational Lensing Experiment) survey from the Astronomical Observatory of the University of Warsaw.

A physicist investigating black holes has found that, in an expanding universe, Einstein’s equations require that the rate of the universe’s expansion at the event horizon of every black hole must be a constant, the same for all black holes. In turn this means that the only energy at the event horizon is dark energy, the so-called cosmological constant. The study is published on the arXiv preprint server.

“Otherwise,” said Nikodem Popławski, a Distinguished Lecturer at the University of New Haven, “the pressure of matter and curvature of spacetime would have to be infinite at a horizon, but that is unphysical.”

Black holes are a fascinating topic because they are about the simplest things in the universe: their only properties are mass, electric charge and angular momentum (spin). Yet their simplicity gives rise to a fantastical property—they have an event horizon at a critical distance from the black hole, a nonphysical surface around it, spherical in the simplest cases. Anything closer to the black hole, that is, inside the event horizon, can never escape the black hole.