Telescopes from the ground are bigger, but have to fight the atmosphere. Here’s how to win.
In astronomy, seeing farther and fainter than ever before requires three simultaneous approaches.
1.) Building bigger telescopes, gathering more light and yielding higher resolutions.
2.) Upgrading your instruments, optimizing the data from each arriving photon.
3.) Overcoming the distortive effects of Earth’s atmosphere.
The easiest way to overcome the atmosphere is from space, avoiding it entirely.
However, space telescopes are expensive, hard to service, and size/payload-limited.
Significantly larger telescopes can be constructed on the ground, where Earth’s atmosphere is unavoidable.
Even at high altitudes, with smooth, dry air and cloudless skies, atmospheric distortion is severely limiting.
That’s where the science of Adaptive Optics comes in.
A portion of any incoming light is immediately analyzed for identifiable distortions of known, point-like sources.
Algorithms compute the shape of a mirror required to “undistort” that light.
A secondary mirror “adapts” its shape to counteract atmospheric distortion.
This clever scheme creates a crisp image that can surpass even Hubble’s capabilities.
This decade, the GMTO and ELT will become Earth’s first 30-meter-class telescopes.
The NSF just granted $17.5M to GMTO, including developing seven adaptive secondary mirrors working together, simultaneously.
Equipped with this novel technology, direct imaging of rocky exoplanets may finally become possible.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.Ethan Siegel is the author of Beyond the Galaxy and Treknology. You can pre-order his third book, currently in development: the Encyclopaedia Cosmologica.