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.
â¢ It would take 100,000 years to cross the Milky Way at the speed of light. Just to gain another reference point, our nearest spiral galaxy, the Andromeda galaxy (M31) is 2.4 to 2.9 million light years from us, and it is about 250,000 ly in diameter. Very big! But, consider the size of the known Universeâ156 billion ly wide!