FEATURE: Explainer: radio astronomy
There’s more to the night sky than the human eye can see. This image of the Crab Nebula combines visible light (green), radio waves (red) and X-ray (blue). Image: NASA/CXC/ASU/J. Hester et al, NASA/HST/ASU and NRAO/AUI/NSF Humans have always had a deep affinity with the night sky. Over millennia the stars have guided us in our travels, provided a grand canvas for the great stories of mythology and invoked a sense of wonder that has pushed us to question and understand our place in the universe. The human experience with the night sky repeats across cultures, representing a significant touchstone in our shared heritage. For most of human existence, we have used our unaided eyes to explore the universe. The eye is an amazing, self-assembling telescope, consisting of a lens of approximately 5mm diameter, an exposure time of roughly 1/15 of a second, and a filter that passes wavelengths of electromagnetic radiation between 400...