Even if only subtly, everything changes with time. Many long-term changes are an intuitive part of day-to-day life. Technology advances. People age. Galaxies are evolving too, although far too slowly to detect in a person's lifetime. But pictures of far away galaxies are snapshots of them from the distant past. So, by comparing with those nearby we can still see how galaxies evolve over the roughly 14 billion year history of the universe.

I study distant galaxies and quasars, which appear very small and faint on the sky. One way to do this is with the Hubble Space Telescope (HST), which takes sharp pictures because it is above the blurring effects of the atmosphere. Another is with large ground-based telescopes employing adaptive optics (AO), using a laser beam or a bright star nearby on the sky to measure and counteract that effect. Above is a comparison I've made with an easily-visible galaxy that's "close to us", after combining HST and AO on one of the twin 10-meter Keck Telescopes.

The current generation of large telescopes have apertures between 8 and 10 meters in diameter, and are built on remote mountaintops that afford the clearest views. Examples are the twin Gemini Telescopes - one of which is located in Hawaii, in the northern hemisphere; the other in Chile, in the southern hemisphere. Together they can access the whole sky, and each is big enough to study galaxies near the edge of visible universe, seen as they were just a few billion years after the universe began.

AO on bigger telescopes will be even more challenging, but necessary to observe the first galaxies. This is the scientific rationale behind the Thirty-Meter Telescope (TMT).

The huge size and infrastructure requirements of the TMT effectively limits it to be on a mountain already developed for astronomy, now selected to be Mauna Kea in Hawaii. But future telescopes may benefit from a truly remote location, such as near one of the poles. I am using robotic testing equipment to explore the world's northernmost high mountains. The intensely cold, dry, and calm air make these potentially the best astronomical sites on the planet.