The Milky Way Galaxy’s Dust Bunnies Are Now Mapped in 3-D
published during a waning crescent moon.


From the stardust of our bodies to the intergalactic dust of our Milky Way galaxy, the universe is a very dusty place. While all this cosmic dust can make for the kind of colorfully magical pics worthy of gracing a Lisa Frank Trapper-keeper, its ethereal soft blur effect wreaks havoc for astronomers trying to get a clear picture of space. To accurately gauge how much these cosmic filters distort their views, scientists strive to create better maps of the distribution, amount, composition, and size of dust particles throughout the universe. And what’s better than a 2-D map of all this dust? Why, a 3-D one, of course!

Edward F. Schlafly, a Hubble Fellow in the Physics Division at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and his team did just that. Their detailed 3-D map of cosmic dust reaches thousands of light-years in our Milky Way galaxy. The study was published today in The Astrophysical Journal.

The 3-D map will serve as a guide for the Dark Energy Spectroscopic Instrument, a Berkeley Lab-led project, that aims to map more than 30 million distant galaxies. Scientists will use the dust map as a guide to correct for dust’s color-distorting qualities which make distant galaxies appear farther or closer than they actually are.

“The light from those distant galaxies travels for billions of years before we see it,” according to Schlafly in a press release, “but in the last thousand years of its journey toward us a few percent of that light is absorbed and scattered by dust in our own galaxy. We need to correct for that.”

Dust Bunnies

A compressed view of the entire sky visible from Hawaii by the Pan-STARRS1 Observatory. The disk of the Milky Way looks like a yellow arc, and the dust lanes show up as reddish-brown filaments. The background is made up of billions of faint stars and galaxies. Credit: D. Farrow/Pan-STARRS1 Science Consortium, and Max Planck Institute for Extraterrestrial Physics.

Schlafly’s research team used data from two sky surveys conducted with telescopes on Maui and in New Mexico to make maps comparing dust located within one kiloparsec, or 3,262 light-years, in the outer Milky Way with dust located farther away in the galaxy. The two impressive surveys were: Pan-STARRS, a multiyear survey of three-fourths of the visible sky and powered by a 1.4-gigapixel digital camera, and APOGEE, a survey that used infrared spectroscopy to see the light from about 100,000 red giant stars across the Milky Way.

Though scientists have successfully found a good deal of this cosmic dust, there’s still a lot more out there to find. “There is about one-third of the galaxy that’s missing,” Schlafly said, “and we’re working right now on imaging this ‘missing third’ of the galaxy.” Some of this missing data will come from a survey of the southern galactic plane scheduled to complete in May, and also from APOGEE-2, a follow-up survey to APOGEE.

And if all else fails, perhaps astronomers would consider developing a Roomba for space?