Johns Hopkins Astronomer Helps Solve Stardust Mystery

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Images of the Milky Way show lots of stars, of course–but they also reveal lots of other stuff, including mysterious dark bands emanating from starlight. These are called diffuse interstellar bands (DIBs), and they’ve baffled astronomers since they were first discovered in 1922 by Mary Lea Hager, a graduate student at the time.

Astronomers study objects in space by looking at the light they emit. DIBs are interruptions in the light spectrum–which indicates that something between Earth and the star had absorbed that light. But what, and how? The going theory is that unusually large, complex molecules are the culprits, but there’s been no way for astronomers to prove that one way or another.

Until now, that is. Johns Hopkins astronomer Rosemary Wyse is playing a prominent role in the study of DIBs by helping create pseudo-3D maps of the Milky Way. “To figure out what something is, you first have to figure out where it is,” Wyse explains. The maps, which rely on 10 years of data drawing from the UK Schmidt Telescope in Australia, include information about half a million stars.

“The resulting maps showed the intriguing result that the complex molecules thought to be responsible for the DIBs are distributed differently than another known component of the interstellar medium—the solid particles known as dust,” the Hopkins Hub notes.

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