The Eos Cloud is a dark molecular cloud of

Hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

gas located just 94

parsec The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (AU), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...

s from the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

near the edge of the

Local Bubble The Local Bubble, or Local Cavity, is a relative superbubble, cavity in the interstellar medium (ISM) of the Orion Arm in the Milky Way. It contains the List of nearest stars and brown dwarfs, nearest stars and brown dwarfs and, among others, the ...

. The cloud has a small amount of

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

contained within it. It is predicted that in 5.7 million years, the Eos cloud will photoevaporate. The cloud was discovered in 2025 by using H₂ far ultraviolet fluorescent line emission. Its close proximity (one of the closest clouds to Earth) to

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

allows for easier observation of how these

molecular cloud A molecular cloud—sometimes called a stellar nursery if star formation is occurring within—is a type of interstellar cloud of which the density and size permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen, ...

s form and dissipate. The cloud is named after

Eos In ancient Greek mythology and Ancient Greek religion, religion, Eos (; Ionic Greek, Ionic and Homeric Greek ''Ēṓs'', Attic Greek, Attic ''Héōs'', "dawn", or ; Aeolic Greek, Aeolic ''Aúōs'', Doric Greek, Doric ''Āṓs'') is the go ...

, the Greek goddess of the dawn.

References

{{2025 in space Molecular clouds Star-forming regions Local Bubble 2025 in outer space