The Milky Way galaxy has been mapped like never before, and this new study may help solve a mystery about stardust that has puzzled astronomers for nearly a century.
The interstellar medium - the material drifting between the stars - largely remains a mystery to astronomers. This new research could help answer questions concerning the composition and structure of the mixture.
Gas and dust in the interstellar medium are provided from material cast off during the deaths of stars. This same combination of particles also provides much of the material needed to form the next generation of stellar furnaces, as well as the worlds that orbit them.
"There's an old saying that 'We are all stardust,' since all chemical elements heavier than helium are produced in stars. But we still don't know why stars form where they do. This study is giving us new clues about the interstellar medium out of which the stars form," Rosemary Wyse, professor of physics and astronomy at Johns Hopkins University, said.
Diffuse interstellar bands (DIB's) were first discovered in 1922. Some frequencies, or colors, of light from distant bodies are absorbed by the material in the interstellar medium. Different elements and molecules absorb specific wavelengths of light. By studying these absorption lines, astronomers are usually able to determine the chemical makeup of an intervening gas.
However, the lines seen in light passing through the interstellar medium do not conform to any known element or molecule known or theorized. This mystery of these 400 lines in the spectrum of light passing through the material has boggled boffins since for nearly 100 years.
One possible explanation for the mysterious absorption lines would be the presence of large, complex molecules, although their existence has not yet been proven. If a material with these properties could be shown to exist, the knowledge could rewrite the laws of stellar and galactic formation and development.
The Radial Velocity Experiment (RAVE) examined data over a decade, using the UK Schmidt Telescope in Australia, capable of observing as many as 150 stars at once. Information in 500,000 stars was then used to create pseudo-3D maps, expressing the movement of stars through the galaxy.
The vast amount of data allowed astronomers to map the distribution of interstellar medium floating between the stars. Analysis revealed that the proposed large molecules creating the DIB's are distributed differently than other ingredients in the mixture.
"To figure out what something is, you first have to figure out where it is, and that's what this paper does. Larger surveys will provide more details in the future. This paper has demonstrated how to do that," Wyse told the press.
Investigation of the interstellar medium was detailed in the journal Science.