Instant Genius How we look at the Universe with a radio
Mar 13, 2026
Dr Emma Chapman, astrophysicist and radio astronomer at the University of Nottingham, studies the early Universe using radio telescopes. She explains how radio waves reveal hidden gas, spiral arms and structures invisible in light. She describes turning radio signals into images, mapping asteroids with radar, using pulsars to hunt gravitational waves, and ambitious plans for lunar radio arrays.
AI Snips
Chapters
Books
Transcript
Episode notes
Radar Found Ice On Mercury
- Radar observations detected high-reflectivity patches in Mercury's permanently shadowed craters that matched water ice.
- Chapman recounts radar maps later confirmed by a flyby, proving ice exists on Mercury despite its proximity to the Sun.
Pulsars Form A Galactic Gravitational Wave Detector
- Pulsars are rotating neutron stars discovered via radio pulses and now used as galactic-scale timing arrays to detect gravitational waves.
- Chapman points to arrays like the Square Kilometre Array using thousands of pulsars as a timing network.
Radio Is The Only Window To The Cosmic Dark Ages
- Radio waves are the only way to probe the cosmic dark ages before the first stars, because extreme redshift stretches higher-energy light into radio.
- Chapman explains that as the universe expands, early UV/optical emissions are redshifted into radio bands accessible only to radio telescopes.
