Astronomers have a huge problem detecting radiation from space because the Earth's atmosphere blocks most of it and stops it from reaching the surface. Visible light and radio waves get through to telescopes on the ground, and some detectors (infrared, UV and gamma) work when they are high up on mountains.
Biological diversity is the variety of species in a given area. If a new species is added there are more species and therefor greater biological diversity and if one goes extinct there are less species and therefore less biological diversity.
