A clock near a black hole will tick very slowly compared to one on Earth. One year near a black hole could mean 80 years on Earth.
Category: cosmology – Page 188
The new image reveals thin tendrils and clumpy clouds associated with hydrogen gas filling the space between the stars. We can see sites where new stars are forming, as well as supernova remnants.
In just this small patch, only about 1 percent of the whole Milky Way, we have discovered more than 20 new possible supernova remnants where only 7 were previously known.
These discoveries were led by PhD student Brianna Ball from Canada’s University of Alberta, working with her supervisor, Roland Kothes of the National Research Council of Canada, who prepared the image. These new discoveries suggest we are close to accounting for the missing remnants.
Reports that the James Webb Space Telescope killed the reigning cosmological model turn out to have been exaggerated. But astronomers still have much to learn from distant galaxies glimpsed by Webb.
Papers:
Black Hole Energy.
Penrose process for a charged black hole in a uniform.
magnetic field https://arxiv.org/pdf/2106.15010.pdf.
Amplification of waves from a rotating body.
https://arxiv.org/abs/2005.
Hawking-Radiation Recoil of Microscopic Black Holes.
https://arxiv.org/abs/2102.
Polarized light from black hole can be a symbol of Cherenkov radiation generated by Faster Than Light movement under gravity.
https://arxiv.org/abs/2102.
Interactions with cosmic rays could make low-mass dark matter particles detectable by neutrino observatories. But an analysis of two decades’ worth of data shows no signs of the particles.
One question for Paul Sutter, author of “The Remarkable Emptiness of Existence,” an article in Nautilus this month. Sutter is a theoretical cosmologist at the Institute for Advanced Computational Science at Stony Brook University, where he studies cosmic voids, maps the leftover light from the big bang, and develops new techniques for finding the first stars to appear in the cosmos.
What is our universe expanding into?
That’s a great question. The answer, though, is that it’s not a great question. It’s a little tricky, so let me walk you through it. Yes, our universe is expanding. Our universe has no center and no edge. The Big Bang didn’t happen in one location in space. The Big Bang happened everywhere in the cosmos simultaneously. The Big Bang was not a point in space. It was a point in time. It exists in all of our paths.
New Hubble Space Telescope readings show the last moments of a star before it’s devoured by a black hole.
Astronomers used NASA’s iconic Hubble Space Telescope to record detailed observations of a star’s final moments before it was torn apart by a black hole.
As per a NASA blog post, the astronomers used Hubble to focus on the immense gravitational impact on the dying star.
NASA, ESA, Leah Hustak (STScI)
The violent encounter, also known as a “tidal disruption event,” both pulls in material from the star and also shoots radiation out into the cosmos. In the process, a massive donut-shaped gas cloud is formed.
There are few more beautiful sights than the orangey-red disk of our star, the Sun, sinking into the ocean. At sunset it seems a far cry from powerful, hot star we feel at midday and can’t even look at safely. If we were only able to view the Sun at sunset what would we think of it? It would be fair to conclude that it was far weaker than it actually is.
It could be a similar case for astronomers’ observations of the centers of galaxies, suggests a new study.
A new study indicates that scientists have substantially underestimated the energy output of supermassive black hole-powered active galactic nuclei.
The black hole wrapped the layers of the shredded star around itself to form the perfect doughnut of doom.
Powered by supermassive black holes swallowing matter in the centers of galaxies, active galactic nuclei are the most powerful compact steady sources of energy in the universe. The brightest active galactic nuclei have long been known to far outshine the combined light of the billions of stars in their host galaxies.
A new study indicates that scientists have substantially underestimated the energy output of these objects by not recognizing the extent to which their light is dimmed by dust.
“When there are intervening small particles along our line of sight, this makes things behind them look dimmer. We see this at sunset on any clear day when the sun looks fainter,” said Martin Gaskell, a research associate in astronomy and astrophysics at UC Santa Cruz.