45.The center of our galaxy located in the direction of : 1777261
45.The center of our galaxy is located in the direction of the constellation of Orion.
46.Shapley found the distance to the center of the galaxy by studying the distance to open clusters.
47.The disk of the Milky Way is approximately 20,000 ly in diameter.
48.The rapid rotation in the outer disk suggests that our galaxy is more massive than previously thought.
49.Old stars are poor in heavy atoms because there were very few previous generations of stars before the old stars formed.
50.The disk of the galaxy is older than the halo.
51.Spiral tracers tend to be old, luminous stars.
52.Giant molecular cloud complexes are located in spiral arms.
53.The density wave theory explains spurs and branches along the spiral arms.
54.The center of our galaxy shows signs of past eruptions.
55.The period-luminosity relationship is primarily used for main sequence stars.
56.The orbits of halo stars are typically circular and have a low inclination with respect to the disk.
57.Population II stars contain more metals than Population I stars.