A puzzle continues: There is no straightforward description for why or how the gas remains so hot. A Hubble Space Telescope image of an enormous cluster of galaxies known as Abell 1689. Scientists do not fully understand how the gas inside such clusters remains so searingly hot. More questions remain about the physics of galaxy clusters. The hot and cold areas are strong evidence for the impact of magnetic fields on the cooling of the hot gas in galaxy clusters, even more experiments are needed to comprehend exactly what is occurring.
A technician works at the National Ignition Facility. Researchers used the array of 196 lasers to create conditions similar to the hot gas inside massive galaxy clusters.
Experiments point the method to fixing secret that keeps clusters hot.
Galaxies hardly ever live alone. Rather, lots to thousands are drawn together by gravity, forming large clusters that are the biggest things in the universe.
” Galaxy clusters are among the most amazing things in deep space,” said Prof. Emeritus Don Lamb, a University of Chicago astrophysicist and co-author on a brand-new paper published in the journal Science March 9, 2022– one that might point the method towards resolving a decades-long mystery.
Researchers have actually long known that the hydrogen gas in galaxy clusters is searingly hot– about 10 million degrees Kelvin, or roughly the very same temperature level as the center of the sun– which is so hot that hydrogen atoms can not exist. Rather the gas is a plasma including electrons and protons.
The experiment focused the lasers onto a target the size of a cent. Credit: Photo courtesy of National Ignition Facility Operations group
However a puzzle continues: There is no straightforward explanation for why or how the gas stays so hot. According to the normal guidelines of physics, it should have cooled within the age of deep space. But it hasnt.
The difficulty for anybody attempting to resolve this puzzle is that you cant exactly create these type of powerfully hot and magnetic conditions in your backyard.
Nevertheless, there is now one put on Earth where you can: the most energetic laser center worldwide. The National Ignition Facility at Lawrence Livermore National Laboratory is able to produce such extreme conditions– though only for a tiny split second in a volume the size of a dime.
Scientists from UChicago, the University of Oxford, and the University of Rochester interacted to utilize the National Ignition Facility– located in Livermore, California– to develop conditions similar to the hot gas in enormous galaxy clusters. “The experiments performed at the NIF are actually out of this world,” stated Jena Meinecke, who was the very first author on the paper.
The researchers focused 196 lasers onto a single tiny target, producing a white-hot plasma with extreme electromagnetic fields that exists for a few billionths of a 2nd.
This was long enough for them to identify that rather of an uniform temperature, there were cold and hot areas in the plasma.
This dovetails with among the theories that has actually been proposed for how heat is caught inside galaxy clusters. Usually, heat would be easily distributed as electrons clash with each other. The tangled magnetic fields inside the plasma can impact these electrons, causing them to spiral along the direction of magnetic fields– which can avoid them from evenly dispersing and dispersing their energy.
In the experiment they saw that the conduction of energy was reduced by more than a factor of 100.
A Hubble Space Telescope image of a massive cluster of galaxies called Abell 1689. Researchers do not totally understand how the gas inside such clusters remains so searingly hot. Credit: Image courtesy of NASA, ESA, the Hubble Heritage Team– STScI/AURA; J. Blakeslee– NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory; and H. Ford– JHU
” This is an extremely interesting outcome because weve had the ability to reveal that what astrophysicists have proposed is on the ideal track,” said Lamb, the Robert A. Millikan Distinguished Service Professor Emeritus in Astronomy and Astrophysics.
” This is indeed an amazing outcome,” included study co-author University of Rochester Prof. Petros Tzeferacos, who oversaw computer system simulations of the complicated experiment. “The simulations were key to untangling the physics at play in the unstable, magnetized plasma, but the level of thermal transport suppression was beyond what we anticipated.”
The simulations were done with a computer code called the FLASH code, which was established at the University of Chicago and is now hosted at the University of Rochesters Flash Center for Computational Science, which is led by Tzeferacos. The code allows researchers to imitate their laser experiments in elegant detail before they do them, so that they can accomplish the results they look for.
Computer simulations of the experiment showed cold and hot areas (suggested by color) forming around the target. Credit: Image courtesy of Yingchao Lu, University of Rochester
This is important because the researchers only get a valuable couple of chance ats the facility– if something goes wrong, theres no renovate. And since the experiment conditions just last nanoseconds, the researchers need to make certain they make the measurements they need at exactly the best time. This suggests whatever needs to be specifically outlined out far ahead of time.
” Its a difficulty when youre at the very extremes of what can be done, but thats where the frontier is,” said Lamb.
More concerns stay about the physics of galaxy clusters. Though the cold and hot areas are strong evidence for the impact of electromagnetic fields on the cooling of the hot gas in galaxy clusters, further experiments are needed to comprehend exactly what is happening. The group is preparing its next round of experiments at NIF later on this year.
For the moment, though, theyre happy to have actually shed light on why the gas in galaxy clusters is still hot even after billions of years.
” Its a pointer that deep space has lots of amazing things,” said Lamb.
Reference: “Strong suppression of heat conduction in a lab reproduction of galaxy-cluster rough plasmas” by Jena Meinecke, Petros Tzeferacos, James S. Ross, Archie F. A. Bott, Scott Feister, Hye-Sook Park, Anthony R. Bell, Roger Blandford, Richard L. Berger, Robert Bingham, Alexis Casner, Laura E. Chen, John Foster, Dustin H. Froula, Clement Goyon, Daniel Kalantar, Michel Koenig, Brandon Lahmann, Chikang Li, Yingchao Lu, Charlotte A. J. Palmer, Richard D. Petrasso, Hannah Poole, Bruce Remington, Brian Reville, Adam Reyes, Alexandra Rigby, Dongsu Ryu, George Swadling, Alex Zylstra, Francesco Miniati, Subir Sarkar, Alexander A. Schekochihin, Donald Q. Lamb and Gianluca Gregori, 9 March 2022, Science.DOI: 10.1126/ sciadv.abj6799.
The principal detective on the experiment was Prof. Gianluca Gregori of Oxford University. Employee likewise consisted of Oxfords Prof. Alexander Schekochihin, Princetons Archie Bott, and Lawrence Livermore National Laboratorys James Steven Ross.
Financing: U.S. Department of Energy National Nuclear Security Administration, U.S. Department of Energy, National Science Foundation, European Research Council, Engineering and Physical Sciences Research Council.
