(ORDO NEWS) — Galaxies do not exist in a vacuum. Perhaps they do exist (mostly, since even interstellar space contains some matter). But galaxies are usually not single objects. Several galaxies interacting gravitationally can form clusters.
These clusters can interact with each other, forming superclusters. Our galaxy is part of a group of galaxies called the Local Group. This Local Group is part of the Virgo Supercluster, which in turn is part of a group of superclusters called the Laniakea Supercluster.
All of these galaxies have a lot of heat, with extremely high temperatures comparable to the core temperature of our Sun, around 10 million Kelvin.
This temperature is so high that hydrogen atoms cannot exist, and instead of gas, a plasma of protons and electrons is formed. However, this is a problem for physicists, who argue that the plasma should not be so hot.
As Gianluca Gregory, professor of physics at the University of Oxford and one of the authors of the new paper, which details an experiment to recreate the conditions inside a cluster of galaxies, said: a long time (a time comparable to the age of the universe).
So, assuming that heat conduction works in the usual way, we would expect that the original hot core had already dissipated its heat. But observations show that this is not the case.”
The problem with trying to create an experiment to help scientists understand what’s going on is that the temperatures are so high that it’s nearly impossible to do so.
Unless you have 192 lasers working at the same time. You can find it at the National Laser Facility located at Lawrence Livermore National Laboratory in Livermore, California.
The NIF is large enough to fit three football fields. Using a series of amplifiers and other equipment, a beam is generated that provides more than 2 million joules of ultraviolet energy and up to 500 trillion watts of power. It is directed at a target the size of a pencil eraser and lasts only a few billionths of a second.
This short period of time was enough for scientists to make the necessary measurements. They found that there are hot and cold spots in the created plasma.
As the theory suggests and this experiment confirms, there are entangled magnetic fields within the plasma that do not allow electrons to scatter uniformly, thereby preventing heat from being dissipated by ordinary heat conduction.
With the National Ignition Center’s laser, scientists only have a few tries to get it right. And since the experimental conditions last only a few billionths of a second, scientists must ensure that everything is set up and working correctly, including taking measurements.
To do this, University of Rochester professor Petros Tseferakos, who heads the Flash Center for Computational Science at the University of Rochester, used a computer code called FLASH (multiphysics multiscale simulation public domain code) to pre-simulate the experiment so that when it comes time to run the experiments, everything goes right.
This experiment shows how difficult it is to test some scientific theories. But it is these theories that need to be tested if we are to better understand the universe and how it works.
For some of us, knowledge alone is reason enough to continue doing science. However, sometimes in the process we get something that we can use for ourselves here on Earth, or in space when we become a space race.
Later this year, the team will conduct new experiments to find out exactly what happens to the gas inside galaxy clusters. Who knows where this information will lead us? But 192 powerful lasers creating conditions inside the core of a star… to say the least, it’s just great.
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