Post by Andrei Tchentchik on Jun 24, 2019 15:40:54 GMT 2
(.#213).- How our galaxy was born after the Big Bang.
How our galaxy was born after the Big Bang.
VIDEO - For the first time, a team has managed to model the life of a spiral galaxy, similar to our Milky Way, from birth to today.
How are the galaxies born, these majestic formations in which billions of stars are formed? This apparently banal question had until now been left unanswered. The overall scenario has been taking shape for several years, but all attempts to numerically model the valuable accumulated knowledge had failed. A team of Swiss researchers from the Institute of Theoretical Physics and the Zurich Institute of Astronomy, as well as astrophysicists from the University of California, has just completed this feat for the first time.
Below, the formation of a spiral galaxy seen from above and in profile, since after the Big Bang (about 100 million years after the original explosion), until today, 13 billion and a half years later.
Video YouTube : Modeling the formation of a spiral galaxy.
Duration: 2m40s.
Vidéo YouTube : Modeling the formation of our spiral galaxy '' The Milky Way ''.
Durée : 1m46s.
The initial parameters used for this modeling come from the observation. The echo of the Big Bang can indeed be detected in the sky by specialists. It gives vital information (density, temperature, composition, etc.) on the gas cloud that followed the gigantic explosion. The researchers then choose a small square of sky and enter the corresponding values of the echo in their equations. The area potentially contains billions of galaxies. "To avoid too long calculations, the team quickly zoomed in on one of the clumps of material in which galaxies can form," explains figaro.fr Romain Teyssier, professor at the University of Zurich and researcher at the Center of atomic and alternative energy studies (CEA) specialized in numerical modeling of galaxies.
Thousands of hours of calculation
Within this halo of dark matter - a compound that is sensitive only to the forces of gravity - the classical material, gas (in greenish gray in the video), continues to compress and curl up forming arm around the galactic core (probably a black hole). "This is the first time a team has managed to recreate, from the primitive cloud, a realistic galaxy. Its behavior and appearance are strangely reminiscent of our Milky Way, "enthuses Romain Teyssier. "The physics equations have not changed. The key has been to recreate the starting conditions more precisely in order to better take into account the heterogeneities of the original environment. "
It will then be necessary to multiply the hours of calculations to allow the ERIS modeling to reach its result. For example, a simple current laptop would have taken 171 years to achieve this result. Using Swiss and American supercomputers, it took "only" nine months to repeat the same end-to-end calculation several times.
Remain one or two problems to correct. "The assumptions made for this simulation are not fine enough to allow stars to form between the material arms of a spiral galaxy. But in reality, this case exists even though it may be common ", notes Romain Teyssier. Another limitation is that the formation halo is much smaller in modeling than some theorists predicted. This may also mean that the modeling is still too coarse or that the theorists' forecasts are wrong.
F I N .
How our galaxy was born after the Big Bang.
VIDEO - For the first time, a team has managed to model the life of a spiral galaxy, similar to our Milky Way, from birth to today.
How are the galaxies born, these majestic formations in which billions of stars are formed? This apparently banal question had until now been left unanswered. The overall scenario has been taking shape for several years, but all attempts to numerically model the valuable accumulated knowledge had failed. A team of Swiss researchers from the Institute of Theoretical Physics and the Zurich Institute of Astronomy, as well as astrophysicists from the University of California, has just completed this feat for the first time.
Below, the formation of a spiral galaxy seen from above and in profile, since after the Big Bang (about 100 million years after the original explosion), until today, 13 billion and a half years later.
Video YouTube : Modeling the formation of a spiral galaxy.
Duration: 2m40s.
Vidéo YouTube : Modeling the formation of our spiral galaxy '' The Milky Way ''.
Durée : 1m46s.
The initial parameters used for this modeling come from the observation. The echo of the Big Bang can indeed be detected in the sky by specialists. It gives vital information (density, temperature, composition, etc.) on the gas cloud that followed the gigantic explosion. The researchers then choose a small square of sky and enter the corresponding values of the echo in their equations. The area potentially contains billions of galaxies. "To avoid too long calculations, the team quickly zoomed in on one of the clumps of material in which galaxies can form," explains figaro.fr Romain Teyssier, professor at the University of Zurich and researcher at the Center of atomic and alternative energy studies (CEA) specialized in numerical modeling of galaxies.
Thousands of hours of calculation
Within this halo of dark matter - a compound that is sensitive only to the forces of gravity - the classical material, gas (in greenish gray in the video), continues to compress and curl up forming arm around the galactic core (probably a black hole). "This is the first time a team has managed to recreate, from the primitive cloud, a realistic galaxy. Its behavior and appearance are strangely reminiscent of our Milky Way, "enthuses Romain Teyssier. "The physics equations have not changed. The key has been to recreate the starting conditions more precisely in order to better take into account the heterogeneities of the original environment. "
It will then be necessary to multiply the hours of calculations to allow the ERIS modeling to reach its result. For example, a simple current laptop would have taken 171 years to achieve this result. Using Swiss and American supercomputers, it took "only" nine months to repeat the same end-to-end calculation several times.
Remain one or two problems to correct. "The assumptions made for this simulation are not fine enough to allow stars to form between the material arms of a spiral galaxy. But in reality, this case exists even though it may be common ", notes Romain Teyssier. Another limitation is that the formation halo is much smaller in modeling than some theorists predicted. This may also mean that the modeling is still too coarse or that the theorists' forecasts are wrong.
F I N .
