Osteopenia refers to bone density that is lower than normal peak density but not low enough to be classified as osteoporosis. Bone density is a measurement of how dense and strong the bones are. If your bone density is low compared to normal peak density, you are said to have osteopenia.steopenia refers to bone density that is lower than normal peak density but not low enough to be classified as osteoporosis. Bone density is a measurement of how dense and strong the bones are. If your bone density is low compared to normal peak density, you are said to have osteopenia.
The Milky Way is the second-largest galaxy in the Local Group, with its stellar disk approximately 100,000 ly (30 kpc) in diameter, and, on average, approximately 1,000 ly (0.3 kpc) thick.
Our Milky Way Galaxy is a barred spiral galaxy about 120,000 light-years in diameter containing up too 400 billion stars and possibly just as many planets. Our Solar System is located within the disk of the Milky Way Galaxy, around 27,000 light-years from the Galactic Center of the galaxy. Supermassive black holes are believed to sit at the center of most galaxies. Our Milky Way Galaxy is part of a 'Local Group' of galaxies in which the galaxies move relative to each other.