What does it mean by saying "our section of the Milky Way galaxy"? If the section is somehow larger, does that mean that the Milky Way galaxy is also larger?
The Earth is on that little strip at the bottom center of that picture, which looks like it's crossing between two of the larger arms.
Because the galaxy is disc-like and Earth is located about halfway between the center of the disc and it's edge, we're not in a great place to get a good perspective of how the galaxy actually looks. We basically watch stuff spin around us and try to estimate what it looks like from a top-down view.
The study concludes that parts of what we previously attributed to other arms actually belong to the arm that Earth is located on, making the arm longer than previously estimated.
No, in this context, the section is probably the angle of the sector (in a disk) that contains the Local Arm which they claim is actually bigger than previously thought. They also claim it is still shorter than other arms so the size of the galaxy is still within estimate.
https://en.wikipedia.org/wiki/File:Artist%27s_impression_of_...
The Earth is on that little strip at the bottom center of that picture, which looks like it's crossing between two of the larger arms.
Because the galaxy is disc-like and Earth is located about halfway between the center of the disc and it's edge, we're not in a great place to get a good perspective of how the galaxy actually looks. We basically watch stuff spin around us and try to estimate what it looks like from a top-down view.
The study concludes that parts of what we previously attributed to other arms actually belong to the arm that Earth is located on, making the arm longer than previously estimated.