It is generally accepted that our galaxy has a diameter of nearly 100,000 light-years. However, findings of a new research, published in the Astrophysical Journal, suggest that the Milky Way may actually be 50% larger than previously thought.
The Milky Way is a spiral galaxy containing our solar system. From Earth, the Milky Way appears as a band because its disk-shaped structure is viewed from within, but if you could see it from the outside, you’d see spiral arms revolving around a central mass. Now, researchers believe it’s time we make a correction regarding its estimated size.
Rensselaer Polytechnic Institute Professor Heidi Jo Newberg and his team revisited astronomical data from the Sloan Digital Sky Survey; they report that the “Monoceros Ring” — a band of stars wrap around our galaxy three times — are actually a part of the Milky Way. If this is indeed the case, then the galaxy is 50% larger than previously believed.
“For 15 years, there’s been a controversy in the field where half the astronomers think it’s a tidal stream and half the astronomers think it’s something in the disk. I was in the stream camp,” Heidi Newberg from the Rensselaer Polytechnic Institute in New York, and a co-author of the paper, said in an email. “It now looks to me like it’s part of the disc.”
Yan Xu, a scientist at the National Astronomical Observatories of China and also an author of the paper believes that there may be even more ripples we have yet to discover.
“Going into the research, astronomers had observed that the number of Milky Way stars diminishes rapidly about 50,000 light years from the center of the galaxy, and then a ring of stars appears at about 60,000 light years from the center,” said Xu. “What we see now is that this apparent ring is actually a ripple in the disk. And it may well be that there are more ripples further out which we have not yet seen.”
In some aspects, figuring out the parameters of the Milky Way galaxy is even more difficult than figuring out those of other galaxies – because we are from the inside, and our point of view is rather limited.
“Extending our knowledge of our galaxy’s structure is fundamentally important,” said Glen Langston, NSF program manager. “The NSF is proud to support their effort to map the shape of our galaxy beyond previously unknown limits.”
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