Lifeboat Foundation

Dark energy is believed to have a negative impact on big structures, limiting the formation of such particles.

Contrary to earlier understandings based on Einstein’s theory of general relativity, research from the University of Michigan has now found that the pace of growth of these substantial structures is slower than expected.

Large cosmic structures are predicted to expand at a certain rate as the universe expands, with galaxy clusters and other dense areas expanding faster than empty space.

Continue reading “Universe slows cosmic growth defying the theory of relativity” »

One of the most interesting and important questions in cosmology is, “How much matter exists in the universe?” An international team, including scientists at Chiba University, has now succeeded in measuring the total amount of matter for the second time. Reporting in The Astrophysical Journal, the team determined that matter makes up 31% of the total amount of matter and energy in the universe, with the remainder consisting of dark energy.

“Cosmologists believe that only about 20% of the total matter is made of regular or ‘baryonic’ matter, which includes stars, galaxies, atoms, and life,” explains first author Dr. Mohamed Abdullah, a researcher at the National Research Institute of Astronomy and Geophysics-Egypt, Chiba University, Japan. “About 80% is made of dark matter, whose mysterious nature is not yet known but may consist of some as-yet-undiscovered subatomic particles.”

“The team used a well-proven technique to determine the total amount of matter in the universe, which is to compare the observed number and mass of galaxy clusters per unit volume with predictions from numerical simulations,” says co-author Gillian Wilson, Abdullah’s former graduate advisor and Professor of Physics and Vice Chancellor for research, innovation, and economic development at UC Merced.

After years of dedicated research and over 5 million supercomputer computing hours, a team has created the world’s first high-resolution 3D radiation hydrodynamics simulations for exotic supernovae. This work is reported in The Astrophysical Journal.

Ke-Jung Chen at Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in Taiwan, led an international team and used the powerful supercomputers from the Lawrence Berkeley National Laboratory and the National Astronomical Observatory of Japan to make the breakthrough.

Supernova explosions are the most spectacular endings for massive stars, as they conclude their life cycles in a self-destructive manner, instantaneously releasing brightness equivalent to billions of suns, illuminating the entire universe.

A wild, compelling idea without a direct, practical test, the Multiverse is highly controversial. But its supporting pillars sure are stable.

Some of the world’s leading physicists believe they have found startling new evidence showing the existence of universes other than our own. See more in Season 3, Episode 2, “Parallel Universes.”

#TheUniverse.

Continue reading “The Universe: New Evidence of Parallel Worlds (S3, E2) | Full Episode” »

The “no-hair theorem” of black holes, which greatly simplifies the way we model them, may not be true if an alternative theory of gravity known as the teleparallel formulation is correct, an unpublished paper argues. This could make the study of black holes considerably more complicated, but it would also allow physicists to understand them in ways many have feared they never will.

According to the “no-hair theorem”, a black hole’s mass, electric charge, and spin can tell us everything there is to know about that hole. Anything else we might measure, such as its magnetic moment, can be derived from these three measures.

Crucially, that means that when matter is swallowed by a black hole’s event horizon, all the information contained within it is lost, once the black hole has emitted any gravitational waves or light associated with its meal. It doesn’t matter what elements went into forming a black hole’s predecessor star, or even if it was made of antimatter rather than matter – under the no-hair theorem, it would appear identical to anyone outside its event horizon. The term “hair” is a metaphor for information streaming out of a black hole beyond the point of no return for incoming objects.

A cosmologist explains the mind-bending hypothesis that our universe could have branched off from a black hole singularity in another universe.

The orbits of 27 stars orbiting closely around the black hole at the center of our Milky Way are so chaotic that researchers cannot predict with confidence where they will be in about 462 years. This finding emerges from simulations by three astronomers based in the Netherlands and the United Kingdom. The researchers have published their findings in two papers in the International Journal of Modern Physics D and in the Monthly Notices of the Royal Astronomical Society.

Simulating 27 stars and their interactions with each other and with the black hole is easier said than done. For centuries, for example, it was impossible to predict the motions of more than two interacting stars, planets, rocks, or other objects. It was only in 2018 that Leiden researchers developed a computer program in which rounding errors no longer play a role in the calculations. With this, they were able to calculate the motions of three imaginary stars. Now the researchers have expanded their program to deal with 27 stars that, by astronomical standards, move close to the black hole at the center of the Milky Way.

The simulations of the 27 massive stars and the black hole resulted in a surprise. Although the stars remain in their orbits around the black hole, the interactions between the stars show that the orbits are chaotic. This means that small perturbations caused by the underlying interactions change the orbits of the stars. These changes grow exponentially and, in the long run, make the star orbits unpredictable.

Jayanne English (U. Manitoba), Nathan Deg (Queen’s University) & WALLABY Survey, CSIRO/ASKAP, NAOJ/Subaru Telescope.

Polar ring galaxies are an intriguing class with a distinct and perplexing structure. These galaxies are distinguished by a ring of stars, gas, and dust significantly tilted to the galaxy’s main disk.