Scientists are creating a map of the mysterious galactic clouds where stars are born.

"One of the largest unresolved mysteries in galactic astronomy is how these giant, diffuse clouds form in the interstellar medium. This process plays a key role in the cosmic cycle of birth and death of stars," team leader Professor Michael Burton, of the University of New South Wales School of Physics, said, a UNSW press release reported.

The gas-cloud wombs can be up to 100 light-years long.  Researchers were able to identify the galactic clouds of molecular gas through the carbon monoxide they inherently contain.

The clouds could form when an "ensemble" of small clouds conjoins into one large entity. They are fed by dying stars, and about one star per year is born in their midst in the Milky Way.

"On Earth, carbon monoxide is poisonous - a silent killer. But in space, it is the second most abundant molecule and the easiest to see," Burton said.

The research team examined the galactic clouds with the Mopra millimetre wave telescope that was almost destroyed in a recent brush fire.

The team is also on the hunt for "dark" galactic gas clouds, which are harder to see because they do not contain revealing carbon monoxide. The clouds are believed to be made up of molecular hydrogen, which is so cold it makes detection almost impossible.

Telescopes in Chile and Antarctica are being used to search for evidence of the clouds' carbon atoms, instead of their carbon molecules.

Researchers will use the surveys to "map out" the distribution and movement of these evasive gas clouds.

There is a chance these "dark" clouds could be the source of unexplained gamma rays, "which are produced when high-energy cosmic rays interact with the nuclei of gas atoms or molecules they encounter when travelling through space," the press release reported.

"The source of more than 30 percent of gamma rays remains unidentified - another big mystery our research could throw light on," Burton said.