The lost chunk of what makes up the universe we know has been located
Half of the universe which is not dark matter or energy is, in fact, a mixture of gases that may be responsible for connecting the galaxies somehow in a kind of loose cosmic web, according to the latest research, discovering vast areas previously was unknown to us.
Until now, this sizable portion of the baryonic matter, which makes up to 5% of the universe, could not be found. Researchers from Spain and Argonne National Laboratory proposed their research published in Monthly Notices of the Royal Astronomical Society.
The remaining portion that covers 95% of the universe is made up of dark matter and energy. Stars, planets, galaxies, and everything they contain is called ‘baryonic matter. Astronomers from the beginning knew it was there but were not sure if it was more stars, planets or energy.
“You just presuppose that this was known and say, I can see this, it’s not dark matter or dark energy, well we know that, said lead author Jonas Chaves-Montero, who has done most of this research at the Argonne National Laboratory. But you wonder and find that 50% of this matter is missing, and we didn’t know where it was, and then we understand that the things one take for granted are sometimes not well-understood.”
To find out the true content of baryonic matter, Chaves-Montero and his colleagues formulated a new method of analyzing the cosmological microwave history of the universe, that is the energy released at the time of the Big Bang about 14 billion years ago, and the energy is still on move and releasing even today. As this energy moves through matter, it distorts.
“By detecting those distortions, we were able to conclude the amount of matter that was causing them”, said Chaves-Montero. “We successfully detected the matter, not a certain distant matter, but all the matter that was intercepting and causing this distortion across the universe,” he added.
This technique requires different maps of photons from the beginning of the universe and the maps of galaxy redshifts (shifts in the wavelength of radiation released by celestial bodies). Chaves-Montero and his colleagues created the photon maps using the radio observation from the European Space Agency and studied the galaxy redshifts by analyzing hundreds of thousands of galaxies observed by telescopes in Australia and the United States.
Combining the studies of these maps, researchers were able to detect the distortion signals of the matter that were interacting with the energy waves. And it turned out to be primordial gas, containing 25% helium and 75% hydrogen.
These gases float so far outside the galaxies that even the gravitational pull on them is null, according to the cosmological simulations. Chaves-Montero theorized that they could be forming galaxy filaments (large structures that connect galaxies like nodes on a 3-dimensional spider web).
The theory remains unproven and Chaves-Montero acknowledges that, because he and his team couldn’t measure the exact location of the gas at this time. Still, with these assumptions, he is positive that the map of the universe has become a little clearer.
“Now that we know this, we can use these detections to set some new equations in cosmology,” said Chaves. “Using this information, we can know more about the matter content of the universe, how it evolves, how it expands, and how it develops changes with respect to time. We can set constraints on that.”
Chaves-Montero is hopeful to continue this work and keep on improving the techniques his team has developed. These developments can assist in studying not only the baryonic matter but gravity as well. The team is focused on researching and finding more hidden truths of the universe and its history, and they plan to keep using this new data from cosmological surveys becoming available in the near future.