Scientists may be one step closer to solving a cosmic puzzle that's had astronomers scratching their heads for nearly a century.
It all started in 1922, when American astronomer Mary Lea Heger noticed that certain wavelengths were consistently absent in the light emitted by binary star systems in the constellations Orion and Scorpius. Since then, other scientists have identified many more of these "diffuse interstellar bands."
Subsequent research showed that something in interstellar space was absorbing the missing wavelengths before they reached Earth. Evidence pointed to various complex molecules scattered across the Milky Way, though astronomers have been unable to determine exactly what they are.
Now, two teams of scientists from Johns Hopkins University in Baltimore have created a map that shows where in our galaxy the mysterious molecules are located.
The researchers hope this map--created with the help of new data-processing techniques--will finally make it possible to analyze the composition and properties of the molecules.
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"For the first time, we can see how these mysterious molecules are moving around the galaxy," Dr. Gail Zasowski, a post-doctoral researcher at the university and one of the astronomers behind the new research, said in a written statement. "This is extremely useful and brings in new connections between these molecules and the dynamics of the Milky Way."
For the research, a team led by Zasowki analyzed infrared data from more than 60,000 stars in the densest parts of our galaxy. Another team, led by graduate student Ting-Wen Lan, looked at visible light from more than half a million stars, galaxies, and quasars.
If that sounds like a lot of data to pore over, it is.
“The era of Big Data in astronomy allows us to look at the universe in new ways," Dr. Brice Ménard, a professor of physics and astronomy at the university and a member of both teams, said in the statement. "There is so much to explore with these large datasets. This is just the beginning.”
The map was unveiled in Seattle last week at the 225th meeting of the American Astronomical Society.