Supercomputer turns back cosmic clock

Date:

Share post:

Astronomers have tested a method for reconstructing the state of the early Universe by applying it to 4000 simulated universes using the ATERUI II supercomputer at the National Astronomical Observatory of Japan (NAOJ). They found that together with new observations the method can set better constraints on inflation, one of the most enigmatic events in the history of the Universe. The method can shorten the observation time required to distinguish between various inflation theories.

Supercomputer turns back cosmic clock
Schematic diagram of the evolution of the universe from the inflation (left) to the present (right).
The reconstruction method winds back the evolution from right to left on this illustration
to reproduce the primordial density fluctuations from the current galaxy distribution
[Credit: The Institute of Statistical Mathematics]

Just after the Universe came into existence 13.8 billion years ago, it suddenly increased more than a trillion, trillion times in size, in less than a trillionth of a trillionth of a microsecond; but no one knows how or why. This sudden “inflation,” is one of the most important mysteries in modern astronomy. Inflation should have created primordial density fluctuations which would have affected the distribution of where galaxies developed. Thus, mapping the distribution of galaxies can rule out models for inflation which don’t match the observed data.




However, processes other than inflation also impact galaxy distribution, making it difficult to derive information about inflation directly from observations of the large-scale structure of the Universe, the cosmic web comprised of countless galaxies. In particular, the gravitationally driven growth of groups of galaxies can obscure the primordial density fluctuations.

Supercomputer turns back cosmic clock
(1) The simulations start from a galaxy distribution based on primordial density fluctuations and
(2) performs gravitational many-body calculations to evolve to the current galaxy distribution.
(3) Then the reconstruction method is used to work backwards to the earlier galaxy distribution.
 (4) Finally, the reconstructed galaxy distributions and initial conditions are compared.
This research found that the statistical properties of the reconstructions are very
similar to the initial conditions [Credit: Masato Shirasaki, NAOJ]

A research team led by Masato Shirasaki, an assistant professor at NAOJ and the Institute of Statistical Mathematics, thought to apply a “reconstruction method” to turn back the clock and remove the gravitational effects from the large-scale structure. 




They used ATERUI II, the world’s fastest supercomputer dedicated to astronomy simulations, to create 4000 simulated universes and evolve them through gravitationally driven growth. They then applied this method to see how well it reconstructed the starting state of the simulations. The team found that their method can correct for the gravitational effects and improve the constraints on primordial density fluctuations.

“We found that this method is very effective,” says Shirasaki. “Using this method, we can verify of the inflation theories with roughly one tenth the amount of data. This method can shorten the required observing time in upcoming galaxy survey missions such as SuMIRe by NAOJ’s Subaru Telescope.”

The study was published in Physical Review D.

Source: Center for Computational Astrophysics [February 16, 2021]

Support The Archaeology News Network with a small donation!





ADVERTISEMENT

spot_img

Related articles

Black hole research could aid understanding of how small galaxies evolve

Scientists have solved a cosmic mystery by finding evidence that supermassive black holes prevent stars forming in some...

Scientists have found out why photons flying from other galaxies do not reach the Earth

An international group of scientists, including Andrey Savelyev, associate professor of the Institute of Physical and Mathematical Sciences...

More evidence of water on Mars

River deposits exist across the surface of Mars and record a surface environment from over 3.5 billion years...

First-ever model simulation of the structuring of the observable universe

A team of researchers from the Laboratoire Univers et Theorie (France) coordinated by Jean-Michel Alimi has performed the...

The lonely giant: Milky Way-sized galaxy lacking galactic neighbours

Long ago in a galaxy far, far away, fewer galaxies were born than expected -- and that could...

Astronomers discover new class of cosmic explosions

Astronomers have found two objects that, added to a strange object discovered in 2018, constitute a new class...

NASA completes MESSENGER Mission with expected impact on Mercury’s surface

A NASA planetary exploration mission came to a planned, but nonetheless dramatic, end Thursday when it slammed into...

Hydrogen halo lifts the veil of our galactic home

Sometimes it takes a lot of trees to see the forest. In the case of the latest discovery...