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.
It is the largest galaxy in the local cluster. It has a mass of 400 billion solar masses. (One solar mass is equal to the sun's mass, or 1,989,100,000,000,000,000,000,000,000,000 kilograms.) Compared to Milky Way. The Andromeda Galaxy is 2.5 times as long as the Milky Way.