Astronomy
Principles of Radio Telescopes and Interferometry
Quick fact
The world's largest single-dish radio telescope, FAST in China, is 500 meters in diameter, yet its resolution is still thousands of times worse than the human eye – interferometry solves this by linking telescopes across continents.
Why this is interesting
You can see stars with your eyes, but what about the radio whispers they send out across the universe? How do we 'see' something invisible?