Scientists Use 196 Lasers To Recreate the Conditions Inside Gigantic Galaxy Clusters – “One of the Most Awe-Inspiring Things in the Universe”

National Ignition Facility Technician

A technician works at the National Ignition Facility. Scientists used the array of 196 lasers to create conditions similar to the hot gas inside gigantic galaxy clusters.

Experiments point the way to solving mystery that keeps clusters hot.

Galaxies rarely live alone. Instead, dozens to thousands are drawn together by gravity, forming vast clusters that are the largest objects in the universe.

“Galaxy clusters are one of the most awe-inspiring things in the universe,” said Prof. Emeritus Don Lamb, a University of Chicago astrophysicist and co-author on a new paper published in the journal Science March 9, 2022—one that may point the way towards solving a decades-long mystery.

Scientists have long known that the hydrogen gas in galaxy clusters is searingly hot—about 10 million degrees Kelvin, or roughly the same temperature as the center of the sun—which is so hot that hydrogen atoms cannot exist. Instead the gas is a plasma consisting of protons and electrons.

Laser Experiment Target

The experiment focused the lasers onto a target the size of a dime. Credit: Photo courtesy of National Ignition Facility Operations team

But a puzzle persists: There is no straightforward explanation for why or how the gas stays so hot. According to the normal rules of physics, it should have cooled within the age of the universe. But it hasn’t.

The challenge for anyone trying to solve this puzzle is that you can’t exactly create these kinds of powerfully hot and magnetic conditions in your backyard.

However, there is now one place on Earth where you can: the most energetic laser facility in the world. The National Ignition Facility at Lawrence Livermore National Laboratory is able to create such extreme conditions—though only for a tiny fraction of a second in a volume the size of a dime.

Scientists from UChicago, the University of Oxford, and the University of Rochester worked together to use the National Ignition Facility—located in Livermore, California—to create conditions similar to the hot gas in gigantic galaxy clusters. “The experiments conducted at the NIF are literally out of this world,” said Jena Meinecke, who was the first author on the paper.

The scientists focused 196 lasers onto a single tiny target, creating a white-hot plasma with intense magnetic fields that exists for a few billionths of a second.

This was long enough for them to determine that instead of a uniform temperature, there were hot and cold spots in the plasma.

This dovetails with one of the theories that has been proposed for how heat is trapped inside galaxy clusters. Normally, heat would be easily distributed as electrons collide with each other. But the tangled magnetic fields inside the plasma can affect these electrons, causing them to spiral along the direction of magnetic fields—which can prevent them from evenly distributing and dispersing their energy.

In fact, in the experiment they saw that the conduction of energy was suppressed by more than a factor of 100.

Abell 1689 Galaxy Cluster

A Hubble Space Telescope image of a massive cluster of galaxies known as Abell 1689. Scientists do not fully understand how the gas inside such clusters stays 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 incredibly exciting result because we’ve been able to show that what astrophysicists have proposed is on the right track,” said Lamb, the Robert A. Millikan Distinguished Service Professor Emeritus in Astronomy and Astrophysics.

“This is indeed an astonishing result,” added study co-author University of Rochester Prof. Petros Tzeferacos, who oversaw computer simulations of the complicated experiment. “The simulations were key to untangling the physics at play in the turbulent, magnetized plasma, but the level of thermal transport suppression was beyond what we expected.”

The simulations were done with a computer code called the FLASH code, which was developed at the University of Chicago and is now hosted at the University of Rochester’s Flash Center for Computational Science, which is led by Tzeferacos. The code allows scientists to simulate their laser experiments in exquisite detail before they do them, so that they can achieve the results they seek.

196 Lasers Experiment Computer Simulation

Computer simulations of the experiment showed hot and cold spots (indicated by color) forming around the target. Credit: Image courtesy of Yingchao Lu, University of Rochester

This is critical because the scientists only get a precious few shots at the facility—if something goes wrong, there’s no redo. And because the experiment conditions only last nanoseconds, the scientists have to make sure they make the measurements they need at exactly the right time. This means everything has to be precisely plotted out far ahead of time.

“It’s a challenge when you’re at the very extremes of what can be done, but that’s where the frontier is,” said Lamb.

More questions remain about the physics of galaxy clusters, however. Though the hot and cold spots are solid evidence for the impact of magnetic fields on the cooling of the hot gas in galaxy clusters, further experiments are needed to understand exactly what is happening. The group is planning its next round of experiments at NIF later this year.

For the moment, though, they’re happy to have shed light on why the gas in galaxy clusters is still hot even after billions of years.

“It’s a reminder that the universe is full of amazing things,” said Lamb.

Reference: “Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent 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 investigator on the experiment was Prof. Gianluca Gregori of Oxford University. Team members also included Oxford’s Prof. Alexander Schekochihin, Princeton’s Archie Bott, and Lawrence Livermore National Laboratory’s James Steven Ross.

Funding: 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.

6 Comments on "Scientists Use 196 Lasers To Recreate the Conditions Inside Gigantic Galaxy Clusters – “One of the Most Awe-Inspiring Things in the Universe”"

  1. Very Interesting.
    Some Initial Thoughts
    1.First Thought was 196 lasers are insuffoicient. Needs to be 100 times that.
    2. Reasons are as follows:
    a. Mass of electron vis-a-vis charge of electron
    b. Mass of proton vis-a-vis charge of proton.
    c. Mass of Neutron
    d. Various Sub-Atomic Particles, their Charge and Mass.
    e. 2(a) to 2(d) = Plasma
    3.Entropy and Laws of Thermodynamics at the Gross Level vis-a-vis Entropy and Laws of Thermodynamics at the Quantum Level.
    4. Gravity in the Gross real World vis–vis Quantum Gravity
    5. Measurement of time in billionths of a second to a range of time for the plasma world where temperature becomes irrelevant in the Temperaature- Pressure- Time connumdrum for nucler reactions.
    6. Important first step in the road to Cold Fusion, in my personal opinion.
    7. Reinforced by Experimental results.

    Views expressed are personal and not binding on anyone.

  2. There is only one energy that makes the timeline of our universe so incredibly slow and it uses the strong force between quarks to exist. The catalyst for this energy is simply the pressure of the dark matter of space itself. Once atoms are broken down into quarks with a sufficient enough reaction, it is the extreme pressure of the dark matter of space that causes gravity that keeps the quarks apart indefinitely. Dark matter is made of extremely pressurized electron neutrinos. As they come into the reaction to separate the quarks, they are consequently thrown back out of the reaction as the most powerful radiation in our universe which are gamma rays. This is what black holes are made of and is also the source of all the gamma rays that flow throughout our universe that scientists do not understand where they originate from.
    Science currently thinks that fusion is the ultimate energy source but, after many decades of creating it, is never able to extract more energy out of the reaction than is put into it.
    The massive amounts of energy emanating from all galaxies that we see is due to a quark plasma core. All this energy came from a collision 13.8 billion years ago when our universe turned itself into a gargantuan particle collider no different than the ones here on Earth. The particle colliders create quark plasma shrapnel and our universe created quark plasma shrapnel. The only difference was the size of the objects involved. Fusion is created as a black hole slowly creates normal matter on its surface as it turns into potential energy. Fusion is nothing but a part of the conservation of mass and energy. First, the black hole creates neutrons on the surface with the quarks and the electron neutrinos of space. The neutrons then naturally break down to the first hydrogen atoms. Then, the constantly forming neutrons fuse with the hydrogen to form the first helium using the beta minus decay reaction. This process continues creating heavier elements making the star darker until the light goes out and a crust forms.
    That is why it is quark plasma, not fusion, that drives the energy of our universe.

  3. It’s 192 Lasers, not 196… even Wikipedia has that right-
    How do I know? I worked there, and I know

  4. Frosted Flake | March 15, 2022 at 2:44 pm | Reply

    Sounds a lot like a mediun against which a magnetic space drive might gain traction.

    Yeah. REALLY hot. How much effect is that going to have on, oh, say, the starship Enterprising? Or, for that matter, Red Dwarf?

  5. Vernon Brechin | March 15, 2022 at 6:00 pm | Reply

    Note that in the article it stated that “scientists only get a precious few shots at the facility.” That is because the NIF has always been primarily funded for simulating the compressions that take place in the U.S. thermonuclear weapons arsenal. To learn more about the promises and disappointments of NIF refer to the Wikipedia article on it.

  6. BibhutibhusanPatel | March 16, 2022 at 7:09 am | Reply

    This is the Gravitational field of super massive black hole at the center of galaxy which traps plasma with all heat enegy associated.So,magnetic field of plasma is oriented by gravity in the galaxy clusters.

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