Lifeboat Foundation

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.

Continue reading “Epic Expansion: The Case for Inflationary Cosmology” »

Berkeley researchers have developed an ultra-precise instrument that captures atoms in free fall to search for dark energy, the force accelerating the universe’s expansion.

Experiment captures atoms in free fall to look for gravitational anomalies caused by universe’s missing energy

By Robert Sanders

Continue reading “With a new, incredibly precise instrument, Berkeley researchers narrow search for dark energy” »

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 dark matter, and have even been suggested as the power source of hypothetical spaceship engines in the far future.

However, new theoretical physics 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 light,” 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.

Continue reading “Black Holes and Dark Revelations: Gravitational Waves Provide New Clues to the Composition of Dark Matter” »

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.

Dark energy—a mysterious force pushing the universe apart at an ever-increasing rate—was discovered 26 years ago, and 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. The results are published in the June 11, 2024, issue of Nature Physics.

The experiment, which combines an atom interferometer for precise gravity measurements with an optical lattice to hold the atoms in place, allowed the researchers to immobilize free-falling atoms for seconds instead of milliseconds to look for gravitational effects, besting the current most precise measurement by a factor of five.

New studies suggest the Nancy Grace Roman Space Telescope could detect primordial black holes from the early universe, potentially confirming their role in cosmic inflation and as components of dark matter.

When astrophysicists observe the cosmos, they see different types of black holes. They range from gargantuan supermassive black holes with billions of solar masses to difficult-to-find intermediate-mass black holes (IMBHs) all the way down to smaller stellar-mass black holes.

Continue reading “From the Dawn of Time: Hunting for Primordial Black Holes With NASA’s Roman Space Telescope” »

The study suggests these primordial black holes could have absorbed free quarks and gluons, making them different from typical black holes formed by collapsing stars. They would be incredibly small, yet could account for much of the universe’s dark matter.

For decades, scientists have struggled to explain the lack of visible matter in the universe.