Astronomers Discover 3,000-Light-Year "Break" In One Of Milky Way's Spiral Arms

[Judi Lynn]

Stephen Luntz
By Stephen Luntz
19 AUG 2021

The spiral arms of the Milky Way form more complex shapes than previously recognized. Not long after a whole extra arm was found within our own galaxy, astronomers have discovered a "break" in one of these enormous rivers of stars; an oddly angled 3,000 light-year-long protuberance, looking uncomfortably like bone sticking out of a badly broken limb.

Reporting in Astronomy and Astrophysics, astronomers reveal this "splinter" is the first major structure found in our galaxy at an angle so different to the arm in its in, and yet is host to many well-known nebulae, including the Eagle Nebula, home to the breathtaking Pillars of Creation.

Spiral galaxies aligned face-on to Earth reveal their structures in often exceptional detail, and for almost 60 years we've known our own galaxy has a similar form. Unfortunately, trapped inside as we are, with major features obscured by dust clouds, it's much harder to work out the exact locations of the Milky Way's spiral arms. Most objects within our galaxy don't lend themselves to precise distance measurements with ground-based instruments, leaving attempts to map the way the galaxy's arms snake around it frustratingly inexact.

Other spiral galaxies often have substructures, known as spurs, feathers, and branches, but until now no one knew if any existed in our galaxy. The newly found structure might be a spur, or something for which we have no name. It sits not far off a line between the Sun and the galactic center.

More:
https://www.iflscience.com/space/astronomers-discover-3000lightyear-break-in-one-of-milky-ways-spiral-arms/

[mopinko]

1. there's just so much we dont know.

it's a cool time to be alive, if you are a nerd.