March 21, 2014
Scientists Create The First 360-Degree Virtual Map Of The Milky Way
[ Watch the Video: 360-Degree View of the Milky Way ]
Lawrence LeBlond for redOrbit.com - Your Universe OnlineNASA’s Spitzer Space Telescope has been busy studying stars, asteroids, galaxies and other outer space objects over the past 10 years and a University of Wisconsin team of scientists has now used more than two million images produced by Spitzer to create a virtual 360-degree mosaic of our Milky Way.
The team presented the new interactive map Thursday at the TEDActive 2014 Conference in Vancouver, Canada.
The map is derived from the Galactic Legacy Mid-Plane Survey Extraordinaire (GLIMPSE360) project and is viewable online at www.spitzer.caltech.edu/glimpse360
The 20-gigapixel mosaic is so massive that if were to be printed out, “we’d need a billboard as big as the Rose Bowl Stadium to display it," said Robert Hurt, an imaging specialist at NASA's Spitzer Science Center in Pasadena, Calif. "Instead we’ve created a digital viewer that anyone, even astronomers, can use."
The mosaic uses Microsoft’s WorldWide Telescope visualization platform and despite only capturing about three percent of the night sky, it focuses on a band around the Earth where the plane of the Milky Way lies. It is this band that contains more than half of all the galaxy’s stars that are visible in the night sky.
Spitzer, which was launched in 2003, has spent more than a decade observing the universe, of which 172 days (4,142 hours) has been spent taking images of the disk, or plane, of our Milky Way in infrared light. The new project is the first time that these images have been stitched together into a single expansive view.
Earth and its solar system sits in the outer one-third of the Milky Way on one of its spiral arms. When we look toward the center of the galaxy, we see a crowded, dusty region packed with stars. Visible-light telescopes cannot look very far into this region due to the amount of dust that blocks visible starlight as we peer farther into the cosmos. Infrared light, however, is able to travel through this dust and can give spectacular views of the galaxy’s central region.
"Spitzer is helping us determine where the edge of the galaxy lies," said Ed Churchwell, co-leader of the GLIMPSE team at the University of Wisconsin-Madison. "We are mapping the placement of the spiral arms and tracing the shape of the galaxy."
"For the first time, we can actually measure the large-scale structure of the galaxy using stars rather than gas," added Churchwell. "We've established beyond the shadow of a doubt that our galaxy has a large bar structure that extends halfway out to the sun's orbit. We know more about where the Milky Way's spiral arms are."
Using the GLIMPSE data, astronomers have created the most accurate map of our Milky Way to date, revealing that the central bar of stars within the center of our galaxy is slightly larger than thought. “GLIMPSE images have also shown a galaxy riddled with bubbles. These bubble structures are cavities around massive stars, which blast wind and radiation into their surroundings,” wrote the team.
All this data will allow scientists to build a more global model of stars and star formation within the galaxy. Spitzer is able to look farther into the dark outer reaches of our galaxy, the “backcountry” if you will, and can find faint stars that have previously gone undetected or unexplored.
"There are a whole lot more lower-mass stars seen now with Spitzer on a large scale, allowing for a grand study," said Barbara Whitney of the University of Wisconsin, Madison, co-leader of the GLIMPSE team. "Spitzer is sensitive enough to pick these up and light up the entire 'countryside' with star formation."
The new 360-degree map will not only help scientists, but will guide NASA’s upcoming James Webb Space Telescope to the most interesting sites in the Milky Way where star formation takes place. The JWST is expected to make even more detailed infrared observations of the Milky Way and its inhabitants.
Furthermore, the interactive map is also adding new cosmological puzzles for scientists to ponder, explained Churchwell. He noted that the GLIMPSE team’s data has revealed that interstellar space is filled with “diffuse polycyclic aromatic hydrocarbon gas.”
"These are hydrocarbons — very complicated, very heavy molecules with fifty or more carbon atoms," Churchwell said. "They are brightest around regions of star formation but detectable throughout the disk of the Milky Way. They're floating out in the middle of interstellar space where they have no business being. It raises the question of how they were formed. It also tells us carbon may be more abundant than we thought."
The GLIMPSE data will not only aid astronomers, but is being made available to citizen scientists under the Milky Way Project, where users can help catalog bubbles and other anomalies in the Milky Way.
Churchwell concluded that the data from the survey will keep astronomers busy for years. "It's still up there. It's still taking data. It's done what we wanted it to do, which is to provide a legacy of data for the astronomical community."