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Category: cosmology – Page 50

Hubble Unveils the Supernova That Illuminated a Galaxy

This week’s featured image from the Hubble Space Telescope showcases the spiral galaxy NGC 337, located approximately 60 million light-years away in the constellation Cetus, also known as The Whale.

The stunning image merges observations captured in two different wavelengths, revealing the galaxy’s striking features. Its golden-hued center glows with the light of older stars, while its vibrant blue edges shimmer with the energy of young, newly formed stars. Had Hubble captured NGC 337 about a decade ago, it would have witnessed an extraordinary sight among the galaxy’s hot blue stars — a dazzling supernova illuminating its outskirts.

Named SN 2014cx, the supernova is remarkable for having been discovered nearly simultaneously in two vastly different ways: by a prolific supernova hunter, Koichi Itagaki, and by the All Sky Automated Survey for SuperNovae (ASAS-SN). ASAS-SN is a worldwide network of robotic telescopes that scans the sky for sudden events like supernovae.

Astronomers have measured a black hole spinning at half the speed of light

Astronomers have discovered a new way to study black holes, the mysterious cosmic entities that destroy anything in their path. By observing X-ray bursts from a star being torn apart by a black hole, researchers calculated the black hole’s spin rate for the first time using X-rays. The black hole was found spinning at nearly 50 percent of the speed of light. This research, published in Science, opens new possibilities for understanding black holes’ behavior and evolution.

The discovery dates back to November 2014, when astronomers observed a supermassive black hole in a galaxy 300 million light years away. This black hole ripped apart a star that had ventured too close, an event known as a tidal disruption flare. The flare generated intense bursts of X-rays that were visible from Earth. Since black holes themselves don’t produce many X-rays, researchers saw an opportunity to study this flare closely.

Black holes may not exist as we know them, but fuzzballs might

String theory proposes that all particles and forces are made of tiny, vibrating strings, which form the fundamental building blocks of the universe. This framework offers a potential solution to the long-standing paradoxes surrounding black holes, such as their singularities—infinitely tiny points where the laws of physics break down—and the Hawking radiation paradox, which questions the fate of information falling into black holes.

Fuzzballs replace the singularity with an ultra-compressed sphere of strings, likened to a neutron star’s structure but composed of subatomic strings instead of particles. While the theory remains incomplete, its implications are significant, offering an alternative explanation for phenomena previously attributed to black holes.

To differentiate between black holes and fuzzballs, researchers are turning to gravitational waves—ripples in spacetime caused by cosmic collisions. When black holes merge, they emit specific gravitational wave signatures that have so far aligned perfectly with Einstein’s general relativity. However, fuzzballs might produce subtle deviations from these patterns, providing a way to confirm their existence.

What Is The Ultimate Cosmic Limit?

Go to https://ground.news/HOTU to stay fully informed on what’s happening in and out of our solar system. Subscribe through my link to get 50% off unlimited access.
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Written by ‪@PaulMSutter‬
Check out his fantastic YouTube channel and podcast for more:
/ paulmsutter.
https://www.pmsutter.com/shows/askasp…
And his books which inspired this video: https://www.pmsutter.com/books.

A huge thanks to our Ho’oleilana Patreon supporters — James Keller and Unpunnyfuns.

Edited by Manuel Rubio ‪@ArtandContext‬
Narrated by David Kelly.
Thumbnail art by Ettore Mazza: https://www.instagram.com/ettore.mazz…
Big Bang Animations by Jero Squartini https://www.fiverr.com/share/0v7Kjv using Manim — MIT License, © 2020–2023 3Blue1Brown LLC
Other animations by Siji Sheehan.
Sound Editing by Craig Stevenson.

Galaxies, space videos from NASA, ESO, and ESA
Music from Epidemic Sound, Artlist, Silver Maple and Yehezkel Raz.
Stock footage from Videoblocks, Artgrid and Shutterstock.

00:00 Introduction.
05:07 How Much Could We Ever Know?
21:33 How Big Could We Ever Build?
34:12 How Far Could We Ever Go?
47:25 The Cosmic Limit.
1:09:06 The Limits of Infinity.

Ask Ethan: Do gravitons need to exist?

Which brings us to the big question: what about gravity?

This is something where we can’t be certain, as gravitation remains the only known force for which we don’t have a full quantum description. Instead, we have Einstein’s general relativity as our theory of gravity, which relies on a purely classical (i.e., non-quantum) formalism for describing it. According to Einstein, spacetime behaves as a four-dimensional fabric, and it’s the curvature and evolution of that fabric that determines how matter-and-energy move through it. Similarly it’s the presence and distribution of matter-and-energy that determine the curvature and evolution of spacetime itself: the two notions are linked together in an inextricable way.

Now, over on the quantum side, our other fundamental forces and interactions have both a quantum description for particles and a quantum description for the fields themselves. All calculations performed within all quantum field theories are calculated within spacetime, and while most of the calculations we perform are undertaken with the assumption that the underlying background of spacetime is flat and uncurved, we can also insert more complex spacetime backgrounds where necessary. It was such a calculation, for example, that led Stephen Hawking to predict the emission of the radiation that bears his name from black holes: Hawking radiation. Combining quantum field theory (in that case, for electromagnetism) with the background of curved spacetime inevitably leads to such a prediction.

Mindscape 240 | Andrew Pontzen on Simulations and the Universe

Patreon: https://www.patreon.com/seanmcarroll.
Blog post with audio player, show notes, and transcript: https://www.preposterousuniverse.com/podcast/2023/06/19/240-…-universe/

It’s somewhat amazing that cosmology, the study of the universe as a whole, can make any progress at all. But it has, especially so in recent decades. Partly that’s because nature has been kind to us in some ways: the universe is quite a simple place on large scales and at early times. Another reason is a leap forward in the data we have collected, and in the growing use of a powerful tool: computer simulations. I talk with cosmologist Andrew Pontzen on what we know about the universe, and how simulations have helped us figure it out. We also touch on hot topics in cosmology (early galaxies discovered by JWST) as well as philosophical issues (are simulations data or theory?).

Andrew Pontzen received his Ph.D. in astronomy from the University of Cambridge. He is currently Professor of Cosmology at University College London. In addition to his research in cosmology, he frequently writes popular articles and appears in science documentaries. His new book is The Universe in a Box: Simulations and the Quest to Code the Cosmos.

Mindscape Podcast playlist: https://www.youtube.com/playlist?list=PLrxfgDEc2NxY_fRExpDXr87tzRbPCaA5x.
Sean Carroll channel: https://www.youtube.com/c/seancarroll.

#podcast #ideas #science #philosophy #culture

Latest gravitational wave observations conflict with expectations from stellar models

Almost 300 binary mergers have been detected so far, indicated by their passing gravitational waves. These measurements from the world’s gravitational wave observatories put constraints on the masses and spins of the merging objects such as black holes and neutron stars, and in turn this information is being used to better understand the evolution of massive stars.

Thus far, these models predict a paucity of black hole binary pairs where each black hole has around 10 to 15 times the mass of the sun. This “dip or mass gap” in the mass range where seldom form depends on assumptions made in the models; in particular, the ratio of the two masses in the binary.

Now a new study of the distribution of the masses of existing black holes in binaries finds no evidence for such a dip as gleaned from the that have been detected to date. The work is published in The Astrophysical Journal.