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Astronomy

The Principles Behind Radio Telescopes and Interferometry

Quick fact

The Event Horizon Telescope, an Earth-sized interferometer of radio telescopes, captured the first image of a black hole's shadow despite the black hole being about 55 million light-years away.

Why this is interesting

You can't see a radio wave with your eyes, yet there is an entire universe glowing at radio wavelengths. How do astronomers turn these invisible signals into detailed images?