Cosmologists create 4,000 virtual universes to solve The Big Bang mystery

Cosmologists are pressing rewind on the first instant after the Big Bang by stimulating 4,000 versions of the universe on a massive supercomputer. 

The goal of the experiment is to paint a picture of the immediate aftermath of the Big Bang theory. According to the theory, the observable universe suddenly expanded trillions of times in size in the tiniest sliver of a microsecond. By applying this method used for the simulations to real observations of today’s universe, researchers hope to arrive at an accurate understanding of what this inflationary period looked like.

Long ago, researchers noticed that astrological bodies like galaxies, stars, and other cosmic stellar objects were getting farther from one another. This showed that our observable universe is expanding. Then scientists concluded that there must be an era when the universe was infinitely small, then it started expanding. According to some theoretical physicists, there was a universe that would have ended by a black hole era, consuming all the matter present. When there was nothing more to grasp, the singularity of the black hole started to expand at an incredible rate, termed as Big Bang.  At the early stages, our universe was so dense that it just consisted of plasma. The further expansion caused the temperature to fall and created a multitude of radiation which was traced and graphed as Cosmic MicroWave Background. 

“We are trying to do something like guessing a baby photo of our universe from the latest picture,” study leader Masato Shirasaki, a cosmologist at the National Astronomical Observatory of Japan (NAOJ), wrote in an email to Live Science. 

Having an eye on the Cosmic Microwave Background, the universe shows variations in density with some patches rich in galaxies and others are relatively barren. One hypothesis for this says the uneven distribution of visible matter is that, at the time of the Big Bang, there were already quantum fluctuations, or random, temporary changes in energy, in the tiny, primordial universe, Shirasaki said.  When the universe expanded, these fluctuations would have expanded as well, with denser points stretching into regions of greater density than their surroundings. Gravity would have interacted with these stretched-out filaments, causing galaxies to clump along with them.

Though, gravitational interactions are far more complex than expected, so trying to rewind this inflammatory period to understand how the universe would have looked before is very challenging.

For this, scientists had a new cleaner start. The researchers developed a reconstruction method to do just that. To find out if the reconstruction was accurate, though, they needed some way to test it. So they used NAOJ’s ATERUI II supercomputer to create 4,000 versions of the universe, all with slightly different initial density fluctuations. The researchers allowed these virtual universes to undergo their virtual inflations and then applied the reconstruction method to them, to see if it could get them back to their original starting points.

The reconstruction has been applied to real-world galaxy data, but the new study shows that it can work on the universe’s inflation period too. The next step, Shirasaki said, is to apply the reconstruction to real observations of the cosmic web. This can eliminate many unwanted and wrong stimulations from those 4,000s. Finally, with huge precision, they could predict our baby universe. Those real observations have already been made by a telescope in New Mexico as part of the Sloan Digital Sky Survey. The only thing left now is to verify and eliminate those resultant stimulations.





Leave a Reply