How much matter is there in our universe? This simple question hides a difficult mystery that keeps cosmologists up at night. To get closer to the solution, scientists created the largest and most realistic computer simulation of the evolution of the universe, tracking not only dark matter, but also ordinary matter (such as planets, stars and galaxies).
The simulation shows how galaxies and galaxy clusters form over time, creating what’s called a space grid. It is the largest structure in the universe, and it consists of filaments consisting of ordinary matter, or baryonic matter, and dark matter.
Flamingo mimics the universe
Shortly after the Big Bang, the universe was filled with a nearly homogeneous soup of atoms (mainly hydrogen and helium), dark matter particles, and nearly massless neutrinos. Although the average density of matter decreased over time, dark matter began to clump together under its own gravity. Atoms followed suit, eventually leading to what we see today: a “cosmic web” of galactic clusters and superclusters, each containing billions of nebulae, stars and planets.
Since the 1980s, astronomers have tried to recreate this process in computer simulations. Thanks to the rapid development of computer technology, these simulations are becoming more detailed, both in scale (the amount of space simulated) and resolution (the number of particles or “elements” tracked). FLAMINGO (complex short for simulation of large-scale structures with full hydropower with all-sky mapping to interpret next-generation observations) is the largest and most complex project to date.
You can read more about dark matter on the spider’s web:
The supercomputer has done something amazing
Led by Job Schaie (Leiden Observatory, Netherlands), the international Flamingo team simulated evolution in growing space—a cube with sides 10 billion light-years long. In this region, they tracked the gravitational “cluster” of 300 billion particles, each weighing about 130 million solar masses, the equivalent of an average dwarf galaxy.
The Flamingo Project provides cosmological simulations, including the behavior of baryons, using the hydrodynamic approach. To accurately model phenomena such as galactic winds, the team calibrated their calculations with existing observations using machine learning. Moreover, Flamingo also takes into account the behavior of cosmic neutrinos – elementary particles with a very small but non-zero mass.
– Explanation of scholars.
New Universe simulations are the latest and greatest in every way. The simulations required over 50 million hours. Computer work for all 30,000 processors that make up the DiRAC-COSMA8 supercomputer at Durham University in the UK. The results were published today in three papers in the Monthly Notices of the Royal Astronomical Society.
Two problems for scientists
One reason astronomers are eager to learn more about cosmic evolution is that cosmology suffers from two puzzling problems. First, the current expansion rate of the universe (the Hubble constant) is higher than what would be expected from observations of the cosmic microwave background (the “afterglow” of the Big Bang). This mismatch is sometimes called Hubble tension.
Second, the matter in the universe appears to be slightly less concentrated than the standard cosmological model predicts. This is a problem known as voltage S8. This is what the scientists involved in the Flamingo Project are doing. New simulations may indicate that something is wrong with our standard cosmological model.
So far, the Flamingo team has run 28 slightly different simulations. By comparing the results with actual observations, astronomers hope to deduce the true values of these parameters and properties.
The secret of the decomposition of matter
When studying the universe, astronomers sometimes use the parameter S8. This parameter describes how “clumped” all matter in our universe is, i.e. strongly concentrated. It can be measured precisely using gravitational lensing observations.
The value of S8 can also be predicted using the Standard Model of cosmology; Scientists can adjust the model to the known properties of the cosmic microwave background (CMB), the radiation left over from the Big Bang, and calculate the mass of the resulting matter. Here comes the problem. CMB experiments found a higher S8 value than gravitational lensing studies. Cosmologists don’t know why; they call this discrepancy the S8 tension. The flamingo simulation may help explain why S8 is so tense because it takes into account both dark and regular matter, which influences the formation of structures in the universe.
The flamingo simulation is not only an impressive technical achievement, but also a beautiful representation of our universe. You can admire how galaxies and their clusters form over time, creating unusual patterns and shapes. The simulation also shows how the cosmic web connects these structures into a huge network of threads. Thus this simulation is not only an important tool for exploring the secrets of the universe, but also a source of joy and inspiration for anyone interested in space.
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