The more we look throughout the Universe, the more we convince ourselves about how much matter it has. Furthermore, each of us is living proof that the Universe contains matter – some more than others. As scientists had been making tremendous progress in the latest years when it comes to understanding what matter is and how it works, it was urgent to know just how much it is in the Universe.
First of all, we must take into account that the Universe can be thousands or even millions of times bigger than what astronomers had been able to measure with the most powerful scientific tools they had. With the light itself being limited in speed, it requires a lot of time to arrive to us from the most distant regions of the Cosmos. The 13.8 billion years since the Big Bang will not be enough if the Universe is much larger than what whey’re able to see (aka the Observable Universe).
1,800 galaxy clusters analyzed
Astronomers from the University of California took measurements for the luminous matter and the dark matter from 1,800 galaxy clusters. Thus, they believe to have the best model of the balance between all energy and matter in the Universe. An article from The Astrophysical Journal describes the study: https://iopscience.iop.org/article/10.3847/1538-4357/aba619
The scientists discovered that the Universe is 31.5 percent made of matter and that the rest of it is made up of the dark energy that accelerates its expansion. Coauthor of the study and an astronomer at New Mexico State University, Mr. Anatoly Klypin, declared:
“A huge advantage of using our [measurement] technique was that our team was able to determine a mass for each cluster individually rather than rely on more indirect, statistical methods,”
In fact, there’s not so much matter in the Universe as we might believe. The scientists believe that if every existing atom was equally separated from one another, there would only be six atoms found within each cubic meter of volume.
“However, since we know 80 [percent] of matter is actually dark matter,” says the study coauthor and physicist at University of California, Mr. Mohamed Abdullah. He added:
“in reality, most of this matter consists not of hydrogen atoms but rather of a type of matter which cosmologists don’t yet understand.”
The scientists are obviously referring to the dark matter, the mysterious structure that is supposed to bind stars and galaxies.
What is dark energy
Dark energy represents another mysterious chapter in science. Astrophysicists don’t know what it is, but they know it’s there due to the effects it has for the whole fabric of spacetime. Dark energy is responsible for the permanent expansion of the Universe, and we would certainly like to know why it exists in the first place, meaning what or who put it there. Without this structure, the Universe would have been on its way to collapse into its own gravity. But dark energy makes it expand, and not in an ordinary way. This mysterious form of energy expands the Cosmos at an even accelerated rate, and the discovery baffled the scientists.
Dark energy was discovered in 1998 by two international teams that included the American astronomers Adam Riess and Saul Perlmutter, as well as the Australian astronomer Brian Schmidt.
Finding out what dark matter is and how it works is currently one of the biggest challenges in today’s science. There’s no clue if dark matter is even made of any kind of atoms’ counterfeits. Luckily or not for us, the Universe means a lot more than the regular matter made of atoms that we’re interacting with every day.