Dig into the deepest mysteries of the universe

An international group of researchers has published the most detailed large-field map ever made on the three-dimensional distribution of matter in the universe. The study suggests that the clumping of matter in the universe occurred more slowly than was suggested in previous estimates.

From Earth to superclusters of galaxies, the distribution of matter is not uniform, but it is enlarged by a vast void. The study revealed for the first time a much more accurate picture of the distribution of matter and vacuum.

"If the universe had too much mysterious dark matter or too little enigmatic dark energy, it would be more muddy than today. Conversely, if dark energy is more important and dark matter is less, we would not have the lumpy structures we see today, "says Aniket Sule, chair of the Education and Outreach Committee. the Indian astronomical society.

Dark matter interacts gravitationally with ordinary lumping matter such as stars, galaxies and superclusters, while dark energy explains the observed accelerated expansion of the universe. There is no direct way to detect or study dark matter and dark energy except by examining the footprint that they leave in the large-scale structure. during the evolution of the Universe.

At the moment of the Big Bang, 13.8 billion years ago, all the matter and energy of the universe was concentrated in one point. Once the universe began to expand, the distribution of mass and energy should have been uniform, with the exception of the minimal effect of gravity and quantum fluctuations. Thus, at a given time and place, the distribution of matter and energy will exhibit extremely low infra-microscopic volatility, which will then become the "seed" of the lumps. The incessant attraction of gravity then takes over, and even a small snowball of mass fluctuation into an agglomeration of matter.

About 400,000 years after the Big Bang, just in the blink of an eye in the cosmic scale, a colossal flash has occurred throughout the universe, whose relic is still visible as cosmic background radiation or CMB. The primordial clusters of matter and energy present in the newborn universe left an imprint in the CMB. The very high-precision images obtained by the Planck mission of the European Space Agency have revealed the structure of primordial clusters of the universe of the baby.

What's new today? The earth is a piece of matter surrounded by empty spaces. With 99% of the mass of the solar system concentrated in the sun, it is an example of local irregularity. Even on a larger scale, galaxies and dark matter are not evenly distributed in the universe. Under the effect of gravity and dark matter, they are concentrated in a structure in clusters and filaments in the form of canvas, with enormous gaps between the two. "Just as we expect the anatomical features of the face found in baby photographs to match those of the adult, we can expect that the size in the baby's universe (printed in the CMB) obtained by the Planck mission corresponds to the one we see today, "Sule said.

"The fluctuations measured by Planck are like an accurate spire of the primitive universe, and we measured where the arrow landed with the Subaru telescope's Hyper Suprime-Cam instrument," says Surhud More.

"From the CMB on primordial clusters, we can calculate what should be the size today. Surprisingly, the size is below expectations. This implies that the universe is accelerating a little less than supposed, implying that the amount of dark energy in the universe is a little less than theorized, "said Aniket Sule. If confirmed by other studies, this can have huge implications for new physics, which goes beyond the standard model.

Astronomers estimate that dark matter and dark energy together account for 95% of our universe. Yet we know very little about it. Like a distant galaxy or astronomical object, dark matter can not be seen directly. We can only deduce its presence from the gravitational effect it has on the tissue of space-time. According to Albert Einstein's general theory of relativity, mass, including dark matter, deforms space. As the light travels from distant galaxies to the earth, if it encounters dark matter in its path, then the light bends in the veiled space. As a result, images of galaxies captured by telescopes are slightly distorted; a phenomenon called low gravitational lens.

By analyzing the tiny distortions caused by gravitational lenses, researchers have reconstructed an extremely accurate 3D distribution of dark matter in the universe. The data collected in this study showed how dark matter fluctuations in the sky have changed over the billions of years and how dark energy has influenced this growth of the structure.

HSC is an 820-megapixel camera attached to the 8.2-meter Subaru telescope atop Maunakea, Hawaii. Since 2014, researchers from Japan, Taiwan and the United States led by the Kavli Institute for Physics and Mathematics of the Universe Project (Kavli IPMU). Assistant professor Chiaki Hikage and a collaborative group co-chaired by Surhud More participated in the survey.

"This is only a first step, and the full HSC survey data promises to advance our understanding of dark matter and dark energy," said the researcher. Kavli IPMU chief, Masahiro Takada. HSC continues to take images and the current results are based on only 11% of the complete survey that is expected to be completed by 2020.

IUCAA also participates in the large Synoptic Survey telescope that will explore about 100 times more areas over the next decade with about 100 times more galaxies to map the invisible dark matter and dark energy properties. It is expected that all these will further illuminate dark matter and black energy.

This article was originally published on India Science Wire