Solar System Located in a Plot of Prime Galactic Real Estate After All: A Study

The solar system is located in a plot of prime real estate when it comes to its placement in the Milky Way galaxy, new research conducted by the National Radio Astronomy Observatory (NRAO) reveals.

Located in a structure called the Local Arm, the National Science Foundation’s Very Long Baseline Array (VBLA) indicates that what scientists once thought to be a mere spur is more like a major arm and likely a suburb of one of them.

"Our new evidence suggests that the Local Arm should appear as a prominent feature of the Milky Way," Alberto Sanna of the Max-Planck Institute for Radio Astronomy said in a press release.

Determining the structure of the Milky Way has long proven to be a challenge to researchers for the simple fact that they’re in it. For this reason, mapping the galaxy requires that scientists accurately measure the distances to objects within it – a difficult task that can often lead to a number of uncertainties, including how many arms the Milky Way contains and where they’re located.

To help solve this problem, researchers turned to the VLBA.

By observing objects when Earth is on opposite sides of its orbit around the Sun, astronomers are able to measure the subtle shift in the object’s apparent position in the sky in comparison to background objects.

Called a parallax, it’s the same phenomenon that occurs when a person holds a finger close to his or her nose and alternates closing each eye, causing the finger to appear as if it is moving back and forth. And because the VLBA is able to precisely measure even minute shifts in apparent position, astronomers are able to determine exact distances much farther than previously possible.

Thus, by using the VLBA and this technique, the astronomers were able to more precisely determine the exact location of the solar system.

"Based on both the distances and the space motions we measured, our Local Arm is not a spur,” Sanna said. "It is a major structure, maybe a branch of the Perseus Arm, or possibly an independent arm segment.”

Other discoveries made by the team included new details regarding the distribution of star formation in the Perseus Arm as well as the farther away Outer Arm, which encompasses a warp in the galaxy.