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.
How Big are Galaxies? A minority of the galaxies in the universe are irregular galaxies, which have irregular shapes or structures, and no symmetry in their rotation. The Andromeda Galaxy is the closest to the Milky Way Galaxy, at 2.2 million light-years away. Most of the visible stars in our galaxy are main sequence stars, which bear resemblance to our sun. Our galaxy, the Milky Way, is believed to have up to 400 billion stars.