The spiral galaxy we live in, known as the Milky Way, is a massive place. From outer arm to outer arm, it's a whopping 100,000 light-years across. But using a variety of astronomical instruments, scientists have now confirmed there's a spiral galaxy more than five times bigger than the one we live in, and now we can see what it looks like.
The above image is a composite of spiral galaxy NGC 6872, put together using visible light images from the European Southern Observatory's Very Large Telescope, far ultraviolet light data from NASA's Galaxy Evolution Explorer (GALEX) and infrared light data from NASA's Spitzer Space Telescope. It's a gorgeous image, and all that data combined has confirmed for astronomers what they've long suspected: NGC 6872 is the biggest spiral out there.
The galaxy has been listed among the biggest in the universe for decades, but scientists couldn't definitively call it the largest spiral galaxy because they couldn't see all of it. Now, thanks to GALEX, they can.
"Without GALEX's ability to detect the ultraviolet light of the youngest, hottest stars, we would never have recognized the full extent of this intriguing system," lead scientist Rafael Eufrasio, of NASA's Goddard Space Flight Center in Greenbelt, Md., and the Catholic University of America, said.
From arm to arm, NGC 6872 measures a whopping 522,000 light-years across. How'd it get so big? Eufrasio and his fellow researchers believe it has to do with gravitational interaction with a much smaller nearby galaxy, IC 4970.
"The northeastern arm of NGC 6872 is the most disturbed and is rippling with star formation, but at its far end, visible only in the ultraviolet, is an object that appears to be a tidal dwarf galaxy similar to those seen in other interacting systems," Duilia de Mello, a professor of astronomy at Catholic University, said.
So, after years of speculation, astronomers have crowned the king of the spiral galaxies. Will something else dethrone it? We'll keep watching the skies.
(Via Huffington Post)