Strange Molecules' Map in Our Galaxy Sheds New Light on a Century-Old Riddle
According to a recent study at Johns Hopkins University whose results were published earlier on in January 2015, astronomers have come up with a unique map of mysterious molecules in our galaxy that are suspected to be responsible for some really puzzling characteristics in the light our planet receives from stars.
The astronomers participating in this research, all from Johns Hopkins’ Sloan Digital Sky Survey (SDSS), achieved this by doing an analysis of the light that is emitted by hundreds of thousands of different celestial bodies. They unveiled the map at the 225th American Astronomical Society conference held in Seattle on January 8th.
Brice Menard, a professor in the Department of Physics and Astronomy at Johns Hopkins, termed the sighting of where the enigmatic molecules are situated as fascinating, with another astronomer who played a major role in the research project, Gail Zasowski, adding that creating the new map necessitated using the power of statistical analyses to analyze massive amounts of data.
Astronomers call the intriguing features identified in the light Diffuse Interstellar Bands, or DIBs. They have baffled scientists ever since Lick Observatory’s Mary Lea-Heger discovered them in 1922. As she examined the light from the stars then, she uncovered some unusual lines created by an unknown thing present in the interstellar space between Earth and the stars.
More research then revealed that the mystical lines were a result of various molecules, but nobody could decipher their identity from the thousands present. The new map, created from SDSS data compiled from two parallel studies almost a century later, has revealed their location.
Zasowski, who is a post-doctoral fellow, was in charge of one team that concentrated on the densest sections of the galaxy and used infrared observations that are capable of cutting through the dust clouds and reaching stars that were previously concealed.
Ting-Wen Lan, a graduate student at Johns Hopkins, was in charge of researchers in another survey, which utilized visible light to unearth the puzzling molecules positioned above the plane of our galaxy, where their signals were very faint and more difficult to measure.
Menard, who performed different tasks in the two research teams, also explained that they do not yet have a full map but interesting patterns can already be seen.
Lan's group did an analysis of light rays emanating from more than 500,000 stars, galaxies and quasars and was able to identify the molecules in areas well beyond and above the disk forming the galaxy. Additionally, the group succeeded in seeing the kinds of environments where they were more likely to be located. Some molecules prefer dense spots where gas and dust are found while others like lonelier areas farther away from the stars.
According to Lan, the outcome of the study will be a guide to researchers as they work towards the best laboratory experiments and observations so that the nature of these molecules is fully understood.
Zasowski's group used SDSS data from the APOGEE survey to view the galactic plane concealed behind heavy clouds of cosmic dust. Using infrared light, APOGEE observations enable scientists to view through interstellar dust quite easily and measure the characteristics of stars all over the galaxy.
The researchers were able to detect some of the mysterious properties in front of approximately 60,000 stars situated in an extensive range of environments, and even succeeded in measuring the motion of the molecules, shedding more light on the correlation between them and other dynamics of the galaxy.
Menard says that scientists are getting closer to full understanding of the molecules, adding that the Big Data era in astronomy enables the universe to be viewed in whole new ways. With these massive datasets, and so much to explore, Menard believes that this is just the start of so much to come.
Image credit: T.W. Lan, G. Zasowski, B. Meacutenard, SDSS and 2MASS/UMass/IPAC-Caltech/NASA/NSF