"An accessible introduction to black holes: what they are, how they form, and how scientists find them. This expanded edition includes updated facts and a new chapter on the first-ever photograph of a black hole"--
"The sun is a source of energy for living things. Energy that comes from sunshine is called solar energy. But how does solar energy work? And how can we use solar energy to not only stay on the cutting-edge of technology, but to help keep the environment healthy?"
