If you think current telescopes are powerful, just you wait. A new class of observatories are in the works that could sport mirrors as large as 100 metres (328 feet) across, and have 40 times the observing power of the Hubble Space Telescope. A new study developed by a commission of European astronomers proposes that instruments this large could be built for approximately 1 billion Euros and take 10-15 years to construct.