What were the structure and dynamics of the first materials in the universe?

Scientists who wish to study the beginning of the universe, the processes by which the first materials were created and developed, immediately after the "Big Bang", cannot (unfortunately) use time machines to transport them to the appropriate areas in space and time. Because of this, they try to recreate in different ways the conditions that prevailed in the early, young universe. This is exactly what Prof. Daniel Zeifman of the Department of Particle Physics and Astrophysics at the Weizmann Institute is doing.

Scientists who wish to study the beginning of the universe, the processes by which the first materials were created and developed, immediately after the big bang, cannot (unfortunately) use time machines to transport them to the appropriate regions in space and time. Because of this, they try to recreate in different ways the conditions that prevailed in the early, young universe. This is exactly what Prof. Daniel Zeifman of the Department of Particle Physics and Astrophysics at the Weizmann Institute of Science and former president of the institute is doing.

About 15 years ago, Prof. Zeifman, at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, planned a unique and ambitious research facility, which was nicknamed the "cryogenic storage ring", or "the ring" for short. It is an annular facility that is about 35 meters long, and nearly ten million dollars were allocated for its construction. In this ring, the scientists intended to capture - using electric fields only - molecular ions of the types that were created and existed in the young universe (these are, in fact, the first molecules created in the universe after the Big Bang). The plan was that after capturing these ions, they would cool down to their fundamental internal temperature (energy): the lowest energy at which the molecule can exist, and at which it has almost stopped oscillating. When the molecular ions are subjected to such a "frozen" state, it is easier to study their properties, such as their structure and dynamics. In this way, one can learn, among other things, about the processes of the formation of stars and identify the materials that make them up.

One of the particularly impressive features of the large cryogenic ring is its ability to isolate a single molecule, track it 'personally' - and examine exactly how it is formed and decomposed"

Shortly after the start of construction of the cryogenic ring, Prof. Zeifman was elected to serve as president of the Weizmann Institute of Science. Even before that, together with Dr. Oded Haber and other members of his research group at the institute, he decided to build his own "pigeon ring" here, in his laboratory on the institute's campus. He didn't have millions of dollars, so he settled for a few tens of thousands of dollars. He also didn't have space for a huge ring that was 35 meters long - so he built a facility that was only 50 centimeters long. This device consists of two mirrors that "give" each other the molecular ions. This is how molecular ions can be stored and cooled, although, of course, the possibilities of the "small trap" were less than those of the large cryogenic ring that was being built in Heidelberg.

But over the years it became clear that the construction of the great cryogenic ring requires overcoming a long series of technological and scientific challenges that sometimes seemed insurmountable. However, the scientists and engineers of the Max Planck Institute did not give up, and in the years when Prof. Zeifman served as president of the institute, they faced the challenges and solved the difficulties one by one. Prof. Zeifman, of course, continued to be interested in their work, followed it and participated in consultations regarding solving problems and difficulties that arose along the way.

Recently, there was a cry of "Eureka" from Heidelberg when, against all expectations, the engineers managed to overcome the technological challenges, and the large ring began to operate, with everything cooled to a temperature of about 4 degrees above absolute zero, which led to some surprising research findings. In the way of nature, the first molecules that are examined in such systems are molecular ions of hydrogen and helium (these are the first two elements created in the young universe, and various combinations of them are the first molecules in the universe). The fascinating process that the scientists focused on was the one in which a molecular ion of helium and hydrogen "sucks" (or "attracts") and attaches to itself a single electron from the plasma around it. The "joined" electron neutralizes the molecular ion and breaks it up. That is, it is a destructive factor that interferes and delays the building process of the building blocks of molecular matter.

One of the particularly impressive features of the large cryogenic ring is its ability to isolate a single molecule, and follow it "personally" (that is, not in the statistics of what happens in a large or small group of molecules), and examine exactly how it is formed and decomposed. One by one, slowly.

Thus, for example, the amount of molecular ions of the helium-hydrogen type (HeH+) that exist in the universe, reflects the quantitative relationship between the formation processes of the molecule and its disintegration processes. A small amount of this molecule reflects a situation where the decomposition is greater and faster than the process of its formation. Scientists have assumed for years a certain relationship between these two processes, but the controlled and precise experiments in the Great Cryogenic Ring have shown the creation of a large amount of this molecular ion, and a slow disintegration process beyond belief. This surprising result has significance regarding the environment that existed in the young universe, where the first galaxies and stars were formed. In other words, these findings will require a re-examination of the models regarding the formation processes of the first galaxies and stars in the universe.

In the Great Cryogenic Ring, the scientists investigate how the behavior of simple molecular systems, at a temperature of 2 degrees Kelvin, affects the formation of stars with a temperature of 1 million degrees Kelvin.
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