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Mar 17, 2024

New Insights on How Galaxies are Formed

Posted by in categories: cosmology, education, space travel, supercomputing

Astronomers can use supercomputers to simulate the formation of galaxies from the Big Bang 13.8 billion years ago to the present day. But there are a number of sources of error. An international research team, led by researchers in Lund, has spent a hundred million computer hours over eight years trying to correct these.

The last decade has seen major advances in computer simulations that can realistically calculate how galaxies form. These cosmological simulations are crucial to our understanding of where galaxies, stars and planets come from. However, the predictions from such models are affected by limitations in the resolution of the simulations, as well as assumptions about a number of factors, such as how stars live and die and the evolution of the interstellar medium.

To minimise the sources of error and produce more accurate simulations, 160 researchers from 60 higher education institutions – led by Santi Roca-Fàbrega at Lund University, Ji-hoon Kim at Seoul National University and Joel R. Primack at the University of California – have collaborated and now present the results of the largest comparison of simulations done ever.

Mar 17, 2024

Black Hole Portraits Will Become More Frequent

Posted by in category: cosmology

This year marks the fifth anniversary of the release of the first-ever image of a black hole, which revealed the glowing doughnut of the supermassive black hole called M87*. The research team that produced the image—the Event Horizon Telescope (EHT) Collaboration—recently released a second image of that same black hole, which lies 55 million light years from Earth [1]. This image comes from an updated version of the EHT and confirms key features of the black hole while also revealing changes over time in the pattern of light emanating from the disk surrounding the object. Starting with this release, the collaboration expects to issue increasingly frequent updates in support of the newly developing field of black hole imaging.

“Producing the first image of M87* was a herculean effort and involved creating, testing, and verifying many different schemes and approaches to analyzing and interpreting the data,” says Princeton University astrophysicist Andrew Chael, a member of the EHT Collaboration. “Now we are beginning to transition to a point where we understand our instrument and our analysis frameworks really well, so I think we are going to be releasing results a lot more quickly.”

Supermassive black holes are extremely distant and compact objects, two properties that make them extraordinarily difficult to image. For example, M87* appears to us as no bigger than an orange on the Moon as viewed from Earth. The 2019 image of M87* was pieced together using data collected in April 2017 from eight radio telescopes spread across the globe. All the telescopes in that array collected data simultaneously, allowing scientists to treat them as one giant radio-wave detector. The bigger a radio telescope, the smaller the objects it can image, and an Earth-sized detector opened the possibility of observing sources as small as supermassive black holes. So far, the EHT has imaged M87* and Sagittarius A*, the black hole at the center of the Milky Way (see Research News: First Image of the Milky Way’s Black Hole).

Mar 17, 2024

A Supernova Remnant Shaped by Vortices

Posted by in category: cosmology

The clumpy structure of a ring of gas ejected by the progenitor star of the supernova 1987A could have formed when vortices in the gas interacted.

Mar 17, 2024

Unlocking the Quasar Code: Revolutionary Insights From 3C 273

Posted by in categories: cosmology, physics

Researchers analyzed emission data from quasar 3C 273 using two theoretical models, revealing complexities in understanding quasar behavior and the mechanics of supermassive black holes.

In a new paper in The Astrophysical Journal, JILA Fellow Jason Dexter, graduate student Kirk Long, and other collaborators compared two main theoretical models for emission data for a specific quasar, 3C 273. Using these theoretical models, astrophysicists like Dexter can better understand how these quasars form and change over time.

Quasars, or active galactic nuclei (AGN), are believed to be powered by supermassive black holes at their centers. Among the brightest objects in the universe, quasars emit a brilliant array of light across the electromagnetic spectrum. This emission carries vital information about the nature of the black hole and surrounding regions, providing clues that astrophysicists can exploit to better understand the black hole’s dynamics.

Mar 16, 2024

GALILEO: Scientists propose a new method to search for light dark matter

Posted by in category: cosmology

New research in Physical Review Letters (PRL) has proposed a novel method to detect light dark matter candidates using laser interferometry to measure the oscillatory electric fields generated by these candidates.

Mar 16, 2024

800-mile neutrino beam probes Earth in DUNE experiment

Posted by in categories: cosmology, particle physics

Scientists are eager to tackle perplexing questions using DUNE, such as the mystery of why the universe is made of matter and how black holes arise from exploding stars.

Moreover, they want to understand the potential connections between neutrinos, dark matter, and other yet-to-be-discovered particles.

These caverns will soon be home to four large neutrino detectors, each the size of a seven-story building.

Mar 16, 2024

Dark matter doesn’t exist and the universe is 27 billion years old • Earth

Posted by in category: cosmology

The fabric of the cosmos, as we currently understand it, comprises three primary components: ‘normal matter,’ ‘dark energy,’ and ‘dark matter.’ However, new research is turning this established model on its head.

A recent study conducted by the University of Ottawa presents compelling evidence that challenges the traditional model of the universe, suggesting that there may not be a place for dark matter within it.

Dark matter, a term used in cosmology, refers to the elusive substance that does not interact with light or electromagnetic fields and is only identifiable through its gravitational effects.

Mar 16, 2024

“This Universe Existed before The Big Bang” ft. Roger Penrose

Posted by in category: cosmology

Let’s unravel the mysteries surrounding (our) Big Bang. Was it truly the beginning of everything? ♾️🔍

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Mar 15, 2024

New research suggests that our universe has no dark matter

Posted by in category: cosmology

The current theoretical model for the composition of the universe is that it’s made of normal matter, dark energy and dark matter. A new University of Ottawa study challenges this.

Mar 15, 2024

Do black holes explode? The 50-year-old puzzle that challenges quantum physics

Posted by in categories: cosmology, particle physics, quantum physics

In hindsight, it seems prophetic that the title of a Nature paper published on 1 March 1974 ended with a question mark: “Black hole explosions?” Stephen Hawking’s landmark idea about what is now known as Hawking radiation1 has just turned 50. The more physicists have tried to test his theory over the past half-century, the more questions have been raised — with profound consequences for how we view the workings of reality.

In essence, what Hawking, who died six years ago today, found is that black holes should not be truly black, because they constantly radiate a tiny amount of heat. That conclusion came from basic principles of quantum physics, which imply that even empty space is a far-from-uneventful place. Instead, space is filled with roiling quantum fields in which pairs of ‘virtual’ particles incessantly pop out of nowhere and, under normal conditions, annihilate each other almost instantaneously.

However, at an event horizon, the spherical surface that defines the boundary of a black hole, something different happens. An event horizon represents a gravitational point of no return that can be crossed only inward, and Hawking realized that there two virtual particles can become separated. One of them falls into the black hole, while the other radiates away, carrying some of the energy with it. As a result, the black hole loses a tiny bit of mass and shrinks — and shines.

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