By Chethana Janith, Jadetimes News
A next gen simulation has possibly revealed the unseen elements of our universe.
A next generation simulation may help scientists solve an astrophysics problem.
We can use energy thrown by hydrogen atoms anywhere in the universe to map matter.
Supercomputers crunched billions of values to study ultraviolet Lyman-alpha energy signatures.
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.
In the search for dark matter, hydrogen is special because it’s very plentiful, the lightest element, and as old as the universe itself—a product of the Big Bang. When the single electron in a hydrogen atom moves from one energy level to another, meaning it’s excited and then grounded, it releases a tiny energy signature in the form of photons.
The universe is filled with the plentiful photons of hydrogen atoms, and these can be detected by our increasingly sophisticated instruments. It’s the same spectroscopy that chemists use to analyze samples for purity or components. Scientists in the late 1800s discovered they could see these hydrogen signatures by studying the patterns of lines produced in a spectroscope. Five men identified five types: Balmer, Lyman, Pfund, Brackett, and Paschen.
All but Lyman are in the infrared range of light, while Lyman is in the ultraviolet. For the Lyman series, the spectral lines are named according to how much energy is being released to create them. The shortest distance between energy levels, from the second level back to the first, is called Lyman-alpha. In far outer space, this signature can cluster in shapes called “forests” by researchers. It’s this series highlighted in UC-Riverside’s new PRIYA simulation, which builds on a previous simulation named ASTRID by the same researcher, Simeon Bird.
The Lyman-alpha forests are believed to show us where dark matter is more concentrated, because the hydrogen is drawn into these shapes by the gravity emitted by dark matter. While dark matter has not yet been observed or detected directly, scientists can continue to develop their hypotheses using simulations like PRIYA.
In this paper, Bird and his colleagues-M.A. Fernandez and Ming-Feng Ho-have sharpened the resolution on a specific problem facing theoretical astrophysics. They want to help explain a gap between what models have predicted our universe should look like and the real thing. Something has thwarted the growth of certain galaxies, and it could be supermassive black holes, or it could be a whole new particle we haven’t yet observed.
“It’s not completely convincing yet, but if this holds up in later data sets, then it is much more likely to be a new particle or some new type of physics, rather than the black holes messing up our calculations,” Bird concluded in the statement.
