Simeon Bird

Scientists Explored Hydrogen Forests—and May Have Uncovered Hidden Dark Matter

tomwt — Mon, 05 Aug 2024 18:28:49 +0000

Scientists Explored Hydrogen Forests—and May Have Uncovered Hidden Dark Matter tomwt Mon, 08/05/2024 - 11:28 More CNAS in the Media Caroline Delbert | Popular Mechanics August 05, 2024

POPULAR MECHANICS - Scientists have combined a powerful simulator with data about the universe to explain a large discrepancy in our understanding. The simulation suite, called PRIYA, debuted last year and is helping scientists study a special phenomenon of hydrogen atoms in deep outer space. Now, in a new study, PRIYA has enabled scientists from the University of California Riverside to map likely locations of dark matter based on the light signature of hydrogen “forests” that form around sources of gravity. Their research appears now in the Journal of Cosmology and Astroparticle Physics.

High-tech simulation software has helped astrophysicists and astronomers take a closer look at far-away phenomena, and allowed us to confirm or fine-tune our theories about the universe. A simulation like this is essentially a gigantic, interactive graph of individual particles and the forces that are acting on them. Processing so much data requires a supercomputer that can crunch away for long periods of time. Using a supercomputer shortens that time down from years or even decades on less powerful computers.

In a UC-Riverside statement, senior author Simeon Bird described the effects seen in this study as “shadow puppetry, where we guess the character placed between the light and the screen based on its silhouette.” Often, scientists eliminate the shadows we do understand in order to theorize that something we can’t yet observe, like dark matter, is filling the rest.

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New Map Of "Hydrogen Forest" Supports The Existence Of Dark Matter

tomwt — Wed, 31 Jul 2024 21:49:36 +0000

New Map Of "Hydrogen Forest" Supports The Existence Of Dark Matter tomwt Wed, 07/31/2024 - 14:49 More CNAS in the Media James Felton | IFLScience July 31, 2024

IFLSCIENCE - A team of astrophysicists have mapped the “Lyman-Alpha Forest", and provided further supporting evidence that galaxy and galaxy cluster formations are better explained by dark matter than alternative theories.

While observing the universe, astronomers found that galaxies and galaxy clusters don't behave in the way we would expect. In short, stars at the edge of galaxies move so fast (in most, but not all galaxies) that they should be yeeted off into intergalactic space given the amount of visible mass we can see in those galaxies.

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In the new study, astrophysicists from the University of California, Riverside, used the “Lyman-Alpha Forest" to attempt to indirectly map dark matter. Essentially, they looked at light from distant sources and mapped drops in light along the hydrogen wavelength. These drops in light correspond to matter the light has encountered along the way.

“It’s somewhat like shadow puppetry, where we guess the character placed between the light and the screen based on its silhouette,” Simeon Bird, associate professor of physics and astronomy and lead author of the study, said in a statement.

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Scientists Analyzing Deep Space "Forest" to Map Dark Matter

tomwt — Wed, 31 Jul 2024 15:50:38 +0000

Scientists Analyzing Deep Space "Forest" to Map Dark Matter tomwt Wed, 07/31/2024 - 08:50 More CNAS in the Media Frank Landymore | Yahoo UK July 30, 2024

YAHOO UK - Dark matter, the invisible substance believed to account for over 80 percent of the universe's mass, is not an easy thing to detect. We can see its gravitational pull on visible matter, however — which makes hydrogen, as the most common element out there, a prime candidate to watch for those interactions.

Taking advantage of this, a team of researchers have analyzed how hydrogen absorbs the light from distant sources like galaxies in an effect known as the "Lyman-Alpha Forest," and have applied this in a series of simulations to map the distribution of dark matter throughout the cosmos.

Their resulting study, published in the Journal of Cosmology and Astrophysics, confirms that there's a discrepancy between our observations of the universe and our predictions about its structures — and possibly points to the existence of a never-before-seen type of particle.

The universe is filled with hydrogen atoms, often in clouds of neutral hydrogen which make up most of the interstellar medium. In a spectrum of distant light sources like galaxies and quasars — whose structures are thought to be governed by dark matter's gravity — the areas where hydrogen absorbs the light along its journey to Earth show up as a staggered series of spiked lines that look like a forest.

"These are the atoms and molecules that the light has encountered along the way," said study coauthor Simon Bird, an associate professor of physics and astronomy at the University of California, Riverside, in a statement about the work. "Since each type of atom has a specific way of absorbing light, leaving a sort of signature in the spectrogram, it is possible to trace their presence, especially that of hydrogen, the most abundant element in the universe."

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Physicists Think Dark Matter May Be Responsible for ‘Hydrogen Forest’

tomwt — Tue, 30 Jul 2024 15:13:51 +0000

Physicists Think Dark Matter May Be Responsible for ‘Hydrogen Forest’ tomwt Tue, 07/30/2024 - 08:13 More CNAS in the Media Isaac Schultz | Gizmodo July 29, 2024

GIZMODO - Using a supercomputer, a team of physicists has confirmed a discrepancy between observations of the universe and theoretical predictions about its structure.

The team used PRIYA, a suite of simulations that takes optical light data from two surveys to refine cosmological parameters, to determine constraints on measurements of the universe and its evolution. The team’s research was published earlier this month in the Journal of Cosmology and Astroparticle Physics.

Using PRIYA, the team studied spectrograms, which are images of hydrogen emission lines in the universe. The spectrograms captured the Lyman-Alpha forest, a dense crowd of absorption lines in spectra from quasars, extremely bright light sources in the universe.

In the team’s spectrograms, spikes of missing frequencies indicated the “atoms and molecules that the light has encountered along the way,” said Simeon Bird, a physicist at UC Riverside and co-author of the research, in a university release. “Since each type of atom has a specific way of absorbing light, leaving a sort of signature in the spectrogram, it is possible to trace their presence, especially that of hydrogen, the most abundant element in the universe,” he added.

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