At present, the largest telescope in the world is the 10 meter twin telescopes of the Keck Observatory. In the future these twin telescopes will be dwarfed by other telescopes. Is 15, 20, 25 meter too small? Lets start with the the 30 meter telescope (TMT) which will be put together by some Universities in America. From there we can go to the Euro50 which will have a primary mirror of 50 meters and is planned by institutions in Europe. The Giant Magellan telescope (GMT) will have a mirror of 24.5 meters. The granddaddy of the new telescopes will be the OverQhelmingly Large (OWL) telescope being planned by the European Southern Observatory, it will have a mirror that is 100 meters. These telescopes will be BIG, or rather, HUGE. The Euro50 will be completed in 2013, the OWL will start operations in 2016 and completion in 2021. Who wants to look in a mirror?
Tis better to light just one little candle than to curse the darkness