Recently identified by astronomers, this newly discovered molecular cloud is one of the largest structures in the sky and is among the closest to the Sun and Earth ever detected.
The EOS Cloud is situated at the boundary of your local bubble—a region populated by large gases within the solar system. Image credits: Thomas Müller, HDA & MPIA/Thavisha Dharmawardena, NYU.
Molecular clouds consist of gas and dust, primarily composed of hydrogen, the most prevalent molecule in the universe and essential for the formation of all known stars and planets.
Additionally, these structures harbor other molecules, including carbon monoxide.
Traditional detection methods for molecular clouds often involve wireless and infrared observations, which readily capture the chemical signatures of carbon monoxide.
However, Blakely Burkhart, an astrophysicist from Rutgers University in New Brunswick, and his team took a different approach.
“This is the first molecular cloud discovered by directly seeking out the distant ultraviolet radiation of molecular hydrogen,” Dr. Burkhart stated.
“Our data revealed glowing hydrogen molecules detected through fluorescence in distant ultraviolet light. This cloud truly shines in the dark.”
The new molecular cloud, named EOS, was located approximately 300 light-years from Earth and can be viewed here.
It resides at the periphery of a local bubble, a region filled with gases surrounding the solar system.
Astronomers estimate that these crescent clouds are immense, spanning about 40 months across the sky and having a mass approximately 3,400 times that of the Sun.
They are projected to dissipate within 6 million years.
According to the research team, the EOS cloud poses no threat to Earth or the solar system.
Its proximity offers a unique opportunity to explore the properties of structures within the interstellar medium.
The interstellar medium, composed of gas and dust, fills the space between stars in the galaxy and is a key source for new star formation.
“When you look through a telescope, you observe the solar system in its formative phase, but the exact process remains unclear,” Dr. Burkhart explained.
“The discovery of EOS is thrilling because it allows us to directly measure how molecular clouds form and dissolve, as well as how galaxies transform interstellar gas and dust into stars and planets.”
The EOS Cloud was identified using data from the FIMS-Spear Far-ultraviolet spectrograph aboard the Korean satellite STSAT-1.
“Utilizing distant UV fluorescence technology could redefine our understanding of the interstellar medium, uncover hidden clouds across the galaxy, and even push our exploration further back to the very edge of the universe’s inception.”
The findings are reported in a study published today in the journal Nature Astronomy.
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B. Burke Hart et al. Dark molecular clouds near local bubbles revealed via H2 fluorescence. Nature Astronomy. Published online on April 28, 2025. doi:10.1038/s41550-025-02541-7
Source: www.sci.news
