Hubble Focus: Gravitational Lenses ― Nature’s Giant Telescopes

https://science.nasa.gov/mission/hubble/multimedia/e-books/hubble-focus-gravitational-lenses/ What if you could build a telescope as big as a galaxy, or even bigger? Luckily, we don’t have to imagine, because the universe has already done that for us. “Gravitational Lenses: Nature’s Giant Telescopes” explores some of Hubble’s discoveries involving the cosmic lensing effect created when light is bent, distorted and magnified by massive objects in space. This NASA Hubble Space Telescope downloadable e-book is the seventh edition of the Hubble Focus series. https://science.nasa.gov/mission/hubble/