A vast, long, invisible molecular clouds have been discovered near our solar system

An international team of scientists led by new Brunswick astrophysicists at Rutgers University have discovered one of the largest single structures in the sky, potentially forming the sun and the closest star to Earth ever detected.

The vast ball of hydrogen, long invisible to scientists, was revealed by searching for its main component, molecular hydrogen. The discovery is marked when molecular clouds are first detected in light emitted in the region of Faltraviolet of the electromagnetic spectrum and open a way to further explore using the approach.

Scientists have named the molecular hydrogen cloud “EO” after the Greek goddess of mythology, Dawn’s personification. Their findings are reviewed in a study published in Nature Astronomy.

“This opens up new possibilities for studying the molecular universe,” said Blakely Burkhart, associate professor of physics and astronomy at Rutgers Arts and Sciences, who leads the team and author of the study. Burkhart is also a research scientist at the Center for Computational Astrophysics at the Flatiron Institute in New York.

Molecular clouds are made up of gas and dust. The most common molecule is hydrogen, a fundamental component of stars and planets, and is essential to life. It also contains other molecules such as carbon monoxide. Molecular clouds are often detected using traditional methods such as wireless and infrared observations, which are easy to pick up chemical signatures of carbon monoxide.

In this work, scientists adopted a different approach.

“This is the first molecular cloud discovered by directly searching for the distant ultraviolet emission of molecular hydrogen,” Burkhart says. “This data showed sparkling hydrogen molecules detected via fluorescence in the distance of ultraviolet light. This cloud literally shines in the dark.”

EOS poses no danger to the Earth and the solar system. According to scientists, gas clouds provide a unique opportunity to study the properties of structures within interstellar media due to their proximity.

The interstellar medium, made of gases and dust fills the interstellar space within the galaxy, serves as a source of new star formation.

“When you look at a telescope, you catch the entire solar system with the act of formation, but you don’t know how that will happen,” Burkhart said. “The discovery of EOS is exciting because we can directly measure how molecular clouds form and dissociate, and how galaxies begin to convert interstellar gases and dust into stars and planets.”

The crescent-shaped gas clouds are located approximately 300 light years from Earth. It is located at the edge of a local bubble, a cavity filled with large gases into the space that encompasses the solar system. Scientists estimate that EOS is a wide projection in the sky, measuring about 40 months across the sky, about 3,400 times more mass than the sun. The team is expected to use the model and evaporate in 6 million years.

“The use of distant UV fluorescence emission technology rewrites our understanding of interstellar media, discovers hidden clouds throughout the galaxy, and is uniform to the farthest detectable limits of the dawn of the universe.”

The EOS was revealed to the team with data collected by the File Laviolet Spectrograph, known as the FIMS-Spear (acronym for fluorescence imaging spectrograph), which operates as an instrument for the Korean satellite STSAT-1. Faltraviolet’s spectrographs decompose far-wave light emitted by the material to its component wavelengths, just like the visible light a prism creates a spectrum that scientists can analyze.

The data was only released in 2023, and was released when Burkhart met.

“It was like just waiting to be explored,” she said.

The findings underscore the importance of innovative observational techniques in promoting understanding of the universe, Burkhart said. She said that EOS is dominated by molecular hydrogen gas, but most are “co-dark.” This means that it does not contain much of the material and does not release the distinctive signatures detected by traditional approaches. It explains how EOS escaped long-standing identification, researchers said.

“The Cosmos story is a story of billions of years of atomic reorganization,” Burkhart said. “The hydrogen currently in the EOS cloud existed at the time of the Big Bang and eventually fell into the galaxy and merged near the sun. So it was a long journey of 13.6 billion years for these hydrogen atoms.”

The discovery manifested as a surprise.

“When I was in graduate school, I was told that I couldn’t observe molecular hydrogen directly easily,” says Dharmawardena of NYU. “It’s kind of wild to be able to see this cloud with data we didn’t expect to see.”

EOS is named after the proposed NASA space mission supported by Burkhart and other members of the team. The mission aims to explore the origins of stars by studying the evolution of molecular clouds and broaden the approach to detecting molecular hydrogen in larger bands of galaxies.

The team is scrutinizing data on molecular hydrogen clouds both near and far. A study published by Burkhart and others using James Webb Space Telescope (JWST) as Arxiv prelints reports that they are tentatively finding the furthest molecular gas.

“We may have used JWST to find the hydrogen molecule that is farthest from the sun,” Burkhart said. “So we found both the closest and the farthest using Faltraviolet release.”