Scientists have peered at the shapes of galaxies billions of light years away, but they still don't know exactly what our own galaxy — the Milky Way — looks like. That's because it's impossible to get a wide view of the galaxy from our vantage point within it. It's like trying to draw the blueprint of a building solely from the inside of one of its rooms.
But state-of-the-art analysis by Ye Xu and colleagues from the Purple Mountain Observatory in Nanjing, China, using a star-measuring trigonometry trick called parallax, has revealed some surprising new details about our home galaxy, details that could render all previous artists' impressions of the Milky Way obsolete, reports New Scientist.
Astronomers have long believed that the Milky Way is a spiral galaxy — and the Chinese team's findings do nothing to dispute that — but the numbers, lengths and densities of the galaxy's arms have been hotly debated. One nugget of conventional thinking, however, suggests that the arm that contains our solar system, known as the Local Arm, is a bit, well... puny. It's supposedly much smaller than some of the other arms.
But the new findings offer a major boost to our region's collective self-esteem. Apparently, the Local Arm might turn out to be just as grand as the others.
Perhaps even more surprising, however, is the fact that the new measurements show how the Milky Way is not actually a grand design spiral with well-defined arms at all. Rather, it's a spiral with many branches and subtle spurs. In other words, the look of our galaxy is more haphazard and less symmetrical than many more idealistic renderings might suggest.
Another interesting find was the discovery of a spur that connects our Local Arm with the Sagittarius Arm — a highway of sorts, with stellar street lamps to light the way, that links the arms together in an unexpected fashion.
“This lane has received little attention in the past because it does not correspond with any of the major spiral arm features of the inner galaxy,” wrote the study's authors.
The Chinese team's findings could soon be corroborated by the European Space Agency’s Gaia spacecraft, which is in the midst of a mission to make its own independent three-dimensional map of the galaxy.
Slowly but surely we're forming a more accurate glimpse of our galactic home. The more detailed the map of the Milky Way gets, the better we can understand how our solar system sits in the context of the cosmos that surround it.