The past few decades have seen some clever new ideas in telescope design, such as adaptive optics for ground-based telescopes that allow mirrors to be physically distorted in real time to correct for atmospheric turbulence and achieve sharpness that would otherwise require putting the telescope in space.

But there are more radical changes coming, from improved ways to block the light of a star so as to see orbiting planets to telescopes that use diffraction rather than reflection or refraction to form images and even fairly conventional telescopes of immense size that use a laser-shaped cloud of tiny grains rather than a solid mirror or lens. This video from the PBS Spacetime channel on YouTube explains. It runs about 11 minutes, not counting a little added material at the end responding to comments on previous videos.

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