Friday , September 25 2020

Look at the evolution of the galaxy, from the big bang to the present


To find out how galaxies change over time, scientists created the most complex simulation of a galaxy ever, called TNG50. The data from this simulation was used to create the video above, which shows the evolution of the massive galaxy from near the beginning of the Big Bang universe to the present day.

In the main panel of the video, thicker gas is presented in lighter colors and thinner gas in darker colors, while bottom inserts show dark matter in the lower left, and star and gas distributions in the lower right.

The full simulation is a "universe in a box", according to the Royal Astronomical Society, combining the volume of cosmological simulations with the level of detail typically only seen in studies of individual galaxies.

tng50 galaxy feyon 1
Image of the optical light emitted by the spiral galaxy stars from the TNG50 simulation. D. Nelson (MPA) and the IllustrisTNG team

The total simulated space is more than 230 million light-years across, though it may show phenomena as much as a million times smaller. With this simulation, astronomers can look back at the earliest formation of galaxies and see how they have changed throughout the history of the 13.8 billion-year universe.

To collect the huge amount of data needed for this project, the researchers could not use any old computer – they need a supercomputer Fazel Chen located in Stuttgart, Germany and they used over 16,000 cores working 24/7 more than a year. to build a simulation.

A key part of simulating galaxy movements is modeling dark matter, which we know must exist, but we never directly observed it. The particles that represent dark matter are included in the simulation, as well as star representations, cosmic gas, magnetic fields and supermassive black holes. In total, there are more than 20 billion particles in the simulation.

"Numerous experiments of this kind are especially successful when you get more than you put in," said Dr. Dylan Nelson of the Max Planck Institute for Astrophysics. "In our simulation, we see phenomena that were not explicitly programmed in the simulation code. These phenomena occur naturally from the complex mixing of the basic physical constituents of our model universe. "

A particular finding applies to disk galaxies like our Milky Way. Watching the simulation, the scientists could see how neat galaxies appeared from the young universe, which was chaotic and disorganized. As the universe got older, gas settled in it and new stars were born in increasingly circular orbits.

"In practice, the TNG50 shows that our own Milky Way galaxy with a thin disk is at the height of galactic fashion: Over the past 10 billion years, at least those galaxies that are still forming new stars have become more and more disk-like, and their chaotic internal movements have been significantly reduced, "lead author Dr Analisa Pilpich explained in the same statement. "The universe was much more orderly when it was only a few billion years old!"

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