The Hubble Space Telescope orbits above the Earth's atmosphere, so it produces rock- steady images, unaffected by the 'twinkling' imposed by the Earth's turbulent air. Using 'adaptive optics', we can now minimize that problem for ground-based telescopes. Describe qualitatively how this new technology works, explaining in particular how and to what part of the telescope we make rapid and continuous adjustments to compensate for the blurriness. What essential role do lasers play?
