In a breakthrough, Israeli researchers have measured invisible particles known as cosmic rays deep in dust clouds 400 light-years from Earth.

A peer-reviewed study that detected these previously unobserved particles could help us understand how stars are born in galaxies.

“These cosmic rays are extremely important for understanding the process of new star formation,” lead researcher Professor Shmuel Bialy of the Technion-Israel Institute of Technology’s Department of Physics told The Times of Israel. “This just opens the door to a whole new field of research in modern astrophysics.”

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Biery’s international team used observations from NASA’s James Webb Space Telescope to measure infrared radiation from cosmic rays that passed through the giant nebula Barnard 68 in the distant constellation of Ophiuchus.

The study was published Wednesday in Nature Astronomy.

“No one thought we would be able to observe these cosmic rays because we had never seen them before,” Biery said. “Now we show that it is possible. We were the first to observe it, and the signal was strong and clear.”

Cosmic rays: “high-energy particles”

“We study how stars form, so it’s important for people on Earth,” said Amit Chemke, 27, a master’s student in Bialy’s group and co-author of the research paper. “Our sun formed billions of years ago, but how are other suns formed?”

Chemke told the Times of Israel that the term “cosmic rays” is “confusing” because it is not radiation and has nothing to do with light.

They were discovered and named by Victor F. Hess in 1912, and the name stuck.

“They are actually particles of matter: protons, electrons, and atomic nuclei,” Chemke says. “These high-energy particles fly around the galaxy at nearly the speed of light.”

“They are very energetic and hit dust clouds and nebulae,” he said.

Huge dust and cosmic clouds between stars

A nebula is a huge cloud that exists between stars. Galaxies are filled with these giant clouds, which contain dust and gases such as hydrogen and helium.

“The sun is a grain of salt compared to these clouds,” Beery said.

Some nebulae are created from gas and dust ejected by exploding dying stars. In other regions, new stars are beginning to emerge.

When these cosmic ray particles hit a nebula, they “can penetrate all the way through,” Kemke explained.

These particles cause hydrogen molecules within the nebula to vibrate. These vibrations emit infrared radiation, which the researchers were able to measure.

Inside the nebula, cosmic rays trigger chemical processes that include the production of new molecules such as water, ammonia, and methanol.

“Cosmic rays affect the process of star formation,” Kemke says.

“We said, let’s try it. Why not?’

People have been observing infrared light emitted by huge, hot stars for decades, Biery said. “These hot stars emit strong ultraviolet light in places like the Orion Nebula, for example.”

But the cosmic rays from the nebula are much weaker, and scientists say they are not strong enough to be observed, he said.

Biery said that during the COVID-19 pandemic, he continued to work on decades-old theories about radiation emitted by cosmic rays in nebulae.

“I enjoyed the process of working out the equations and calculating everything, so I just kept going,” he said. “I thought it would be fun even if I didn’t observe it.”

Beery said he has loved physics and astronomy since he was a child.

He grew up in Russia before his family immigrated to Israel. According to his parents, one night he spoke his first words in Russian, exclaiming, “Look, look, stars!”

While a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Bierly befriended Italian astronomer Sirio Belli, who specialized in infrared observations.

Mr Bialy revealed his calculations. “We said, ‘Let’s do it.’ Even if people say we’ll never be able to observe it, why not do it?” he said.

The two set up a telescope at an observatory in Arizona and observed the nebula with “20-hour long exposures. So what? We couldn’t see anything.”

So the two scientists decided to ask if they could conduct their research using NASA’s James Webb Space Telescope, “an instrument that is far more sensitive than any other on Earth.”

The telescope, launched in December 2021, orbits the sun about 1.5 million kilometers (930,000 miles) from Earth.

Beery said that out of every 10 proposals NASA receives for a telescope, only one is selected.

“After several trials, it was approved,” Bialy said. “We had eight hours of research time on the James Webb Space Telescope.”

The Barnard 68 Nebula is about 2 million times larger than the Sun and is cold and dense, with a temperature of about 10 to 20 Kelvin, just above absolute zero. According to predictions, it will collapse in about 200,000 years and a new star will form.

But until that happened, researchers were able to detect infrared radiation emitted by vibrating hydrogen molecules within the nebula.

David Neufeld, a professor of physics and astronomy at Johns Hopkins University who also participated in the study, said the data from NASA’s telescope “opens a whole new window into cosmic-ray astrophysics.”

The research team has now received an additional 50 hours of observational data from space for analysis.

“This allows us to effectively measure the intensity of cosmic rays in many parts of the galaxy,” Biery said. “And eventually, in the coming years, we plan to extend it even further, perhaps to dozens of surrounding nebulae, to measure the distribution of cosmic rays throughout galactic space.” P.J.C.