Try Opera browser FOR FREE here https://opr.as/04-Opera-browser-sabinehossenfelderDark Energy is the name that astrophysicists have given to what ever acceler…
Category: cosmology – Page 56
One of the main scientific objectives of next-generation observatories (like the James Webb Space Telescope) has been to observe the first galaxies in the Universe – those that existed at Cosmic Dawn. This period is when the first stars, galaxies, and black holes in our Universe formed, roughly 50 million to 1 billion years after the Big Bang. By examining how these galaxies formed and evolved during the earliest cosmological periods, astronomers will have a complete picture of how the Universe has changed with time.
As addressed in previous articles, the results of Webb’s most distant observations have turned up a few surprises. In addition to revealing that galaxies formed rapidly in the early Universe, astronomers also noticed these galaxies had particularly massive supermassive black holes (SMBH) at their centers. This was particularly confounding since, according to conventional models, these galaxies and black holes didn’t have enough time to form. In a recent study, a team led by Penn State astronomers has developed a model that could explain how SMBHs grew so quickly in the early Universe.
The research team was led by W. Niel Brandt, the Eberly Family Chair Professor of Astronomy and Astrophysics at Penn State’s Eberly College of Science. Their research is described in two papers presented at the 244th meeting of the American Astronomical Society (AAS224), which took place from June 9th to June 13th in Madison, Wisconsin. Their first paper, “Mapping the Growth of Supermassive Black Holes as a Function of Galaxy Stellar Mass and Redshift,” appeared on March 29th in The Astrophysical Journal, while the second is pending publication. Fan Zou, an Eberly College graduate student, was the lead author of both papers.
The vast expanse of the night sky, a canvas dotted with countless stars, is about to unveil a rare and spectacular phenomenon. Brace yourself for a stellar light show as T Coronae Borealis, a seemingly unremarkable star nestled within the constellation Corona Borealis, is on the brink of a dramatic nova explosion.
T Coronae Borealis, affectionately known as T CrB, is no ordinary star. It’s a binary system, a celestial pattern of two stars locked in a gravitational embrace.
At the heart of this cosmic process lies a white dwarf, the incredibly dense remnant of a once-mighty star. Its partner, a bloated red giant, is in the twilight years of its existence, slowly shedding its outer layers under the relentless pull of the white dwarf’s gravity.
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Is Dark Energy Decaying?
Posted in cosmology
Brian Greene and Michael Levi discuss revolutionary observations that may upend our cosmological understanding.
This program is part of the Big Ideas series, supported by the John Templeton Foundation.
Participants:
Micheal Levi.
Moderator:
Astronomers at MIT, NASA, and elsewhere have a new way to measure how fast a black hole spins, by using the wobbly aftermath from its stellar feasting.
The method takes advantage of a black hole tidal disruption event—a blazingly bright moment when a black hole exerts tides on a passing star and rips it to shreds. As the star is disrupted by the black hole’s immense tidal forces, half of the star is blown away, while the other half is flung around the black hole, generating an intensely hot accretion disk of rotating stellar material.
The MIT-led team has shown that the wobble of the newly created accretion disk is key to working out the central black hole’s inherent spin.
Related: If the Big Bang created miniature black holes, where are they?
The research team thinks that super-color-charged black holes may have impacted the balance of fusing nuclei in the infant universe. Though the exotic objects ceased to exist in the first moments of the cosmos, future astronomers could potentially still detect this influence.
“Even though these short-lived, exotic creatures are not around today, they could have affected cosmic history in ways that could show up in subtle signals today,” study co-author David Kaiser, a professor of physics at the Massachusetts Institute of Technology (MIT), said in a statement.
Now, however, astronomers Fan Zou and W. Niel Brandt, both of Penn State University, have led a team that connected the two mechanisms of black-hole growth from observations and simulations. The results may provide some answers at last.
Related: NASA telescope spots ‘cosmic fireworks’ and faint echos from the Milky Way’s supermassive black hole
“A very big question is how do these supermassive black holes grow so massive?” said Zou while presenting their work at the 244th meeting of the American Astronomical Society in Wisconsin… “To address that, we need to track the overall growth history of these supermassive black holes.”
The Universe’s history, from cosmic inflation to the Big Bang to the present, is known. But whether it’s infinite or not is still a mystery.
Observational astronomy shows that newly discovered young stellar objects (YSOs) in the immediate vicinity of the supermassive black hole Sagittarius A located in the center of our galaxy behave differently than expected. They describe similar orbits to already known young evolved stars and are arranged in a particular pattern around the supermassive black hole.