Astronomers find 3,000-light-year ‘splinter’ in Milky Way’s spiral arm
By Tom Yun, CTVNews.ca Writer
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TORONTO, Ontario (CTV Network) — Astronomers at NASA say they’ve discovered a structure of gas clouds and young stars that form a “break” in the Milky Way galaxy’s spiral arms.
The structure contains young stars and four nebulae, which are interstellar clouds of gas and dust where stars are created, and stretches around 3,000 light-years. NASA likens it to “a splinter poking out from a plank of wood.”
These discoveries were first published in the journal Astronomy & Astrophysics back in June by researchers based in the U.S., Portugal, China and Spain. Similar splinters or breaks have also been observed in other spiral galaxies, but this is the first time it’s been observed in our own galaxy.
Studying the structure of the Milky Way has been a challenge, given the fact that this is the galaxy the Earth is embedded within.
“It’s akin to standing in the middle of Times Square and trying to draw a map of the island of Manhattan,” NASA said in a news release.
The authors set out to learn more about the Milky Way’s structure by focusing on one of the galaxy’s arms – the Sagittarius Arm.
Using NASA’s now-retired Spitzer Space Telescope, they looked for emerging stars within nebulae. Spitzer could detect infrared light within these clouds.
The researchers also used data from the European Space Agency’s Gaia space observatory to measure the distances of the structure.
“Distances are among the most difficult things to measure in astronomy,” said co-author Alberto Krone-Martins in the news release. “It is only the recent, direct distance measurements from Gaia that make the geometry of this new structure so apparent.”
However, astronomers still aren’t sure why galaxies form spiral arms.
“Ultimately, this is a reminder that there are many uncertainties about the large-scale structure of the Milky Way, and we need to look at the details if we want to understand that bigger picture,” said co-author Robert Benjamin in the news release. “This structure is a small piece of the Milky Way, but it could tell us something significant about the galaxy as a whole.”
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