Scientists have noticed a previously unknown feature of our Milky Way galaxy: one of its spiral arms is literally torn apart.
Astronomers have a rough idea of the size and shape of the arms of the Milky Way, so when studying them in a pinpoint, unexpected discoveries can await. However, there are difficulties, scientists cannot see the full structure of the galaxy, because the Earth is inside it. It is as if you were standing in the middle of Times Square and trying to draw a map of Manhattan.
To learn more about our galaxy, the authors focused on the closest part of one of the arms, it is called the Sagittarius Shoulder. The authors used NASA’s Spitzer telescope to search for newborn stars in clouds of gas and dust.
Previously, scientists have deduced a pattern that young stars and nebulae are closely related to the shape of the arms in which they are located. To obtain a 3D image of the arm segment, the scientists used the latest information about the area from ESA (European Space Agency).
The combined data showed that the long, thin structure of the Sagittarius Shoulder is composed of young stars moving at almost the same speed and in the same direction. This group of stars and star-forming gas clouds literally sticks out of the spiral arm.
There are four nebulae in this group:
- Eagle nebula,
- Omega Nebula,
- Trifid nebula,
- lagoon nebula.
Astronomers have yet to fully understand how spiral arms form in galaxies like ours.