Final answer:
Building the next generation of ground-based telescopes is quite challenging due to the difficulty in constructing giant telescope mirrors that are larger than 30 meters, such as those planned for the European Extremely Large Telescope, which consists of numerous smaller mirrors arranged to work together.
Step-by-step explanation:
One of the major challenges in constructing the next generation of ground-based telescopes is indeed the construction of their large mirrors. It is true that creating mirrors larger than 30 meters across is a significant technological hurdle. Due to limitations in manufacturing and transportation, the primary mirrors of these giant telescopes must consist of numerous smaller mirrors. These mirrors are precisely aligned to act in unison, creating a single, effective reflective surface. The European Extremely Large Telescope (E-ELT), for instance, will feature a 39.3-meter primary mirror made of 798 hexagonal mirrors.
Building these telescopes involves sophisticated engineering and technology, particularly in the design of adaptive optics to compensate for atmospheric turbulence, which affects the resolution of images taken from Earth's surface. Moreover, the sheer size and weight of these mirrors pose both manufacturing and structural engineering challenges, requiring innovative solutions to support and accurately position the mirrors.