Visible light corresponds to a very small portion of the electromagnetic radiation emitted by celestial bodies. However, once we built telescopes that could “see” at wavelengths other than those of visible light, our knowledge of astronomy grew exponentially. Because, as we'll see in this episode of the Space Series, each part of the electromagnetic spectrum corresponds to a different "window" onto the Universe. Given, however, that Earth’s atmosphere blocks harmful high-energy radiation from reaching the surface of our planet, in order to “see” the Universe across the entire range of the electromagnetic spectrum, we need not only ground-based but also space-based telescopes.