Transcript: There’s very little direct evidence in astronomy. In a few cases we’ve been lucky enough to have meteorites falling from space. We’ve even had a few free samples of Mars. But most of the evidence of astronomy is gathered remotely. We’ve sent spacecrafts to most parts of the solar system, and they’ve sent back images and other information of radiation received. We’ve used telescopes to explore distant regions of space. We’ve extended our senses across the electromagnetic spectrum with detectors that can measure everything from x-rays and gamma rays to long wavelength radio waves. In astronomy we depend on the extension of our senses through technology but must of the evidence of astronomy is indeed indirect, the radiation that reaches us from throughout the universe.