by Chris Peterson » Mon Nov 02, 2015 5:14 am
harmount wrote:Standing in MS, as I look out toward the galactic arm, am I tangent or perpendicular to the center? Or some where in between? Looking up from the desert floor, it seems that I am not quite perpendicular, but angular to the arm. Just trying to get a bearing... Lynn Harmount
We don't really see a "galactic arm". We're embedded in the disk of the Milky Way. So we see it as a ring that encircles the Earth, brightest and thickest at the galactic center (looking inwards). We only see half this ring at a time, as the other half is below the horizon. In an image like the one here, the planar disk appears curved, but that's just a projection artifact. The centerline of the Milky Way "arch" really is a line.
[quote="harmount"]Standing in MS, as I look out toward the galactic arm, am I tangent or perpendicular to the center? Or some where in between? Looking up from the desert floor, it seems that I am not quite perpendicular, but angular to the arm. Just trying to get a bearing... Lynn Harmount[/quote]
We don't really see a "galactic arm". We're embedded in the disk of the Milky Way. So we see it as a ring that encircles the Earth, brightest and thickest at the galactic center (looking inwards). We only see half this ring at a time, as the other half is below the horizon. In an image like the one here, the planar disk appears curved, but that's just a projection artifact. The centerline of the Milky Way "arch" really is a line.