The U. S. has plans to build a 30-meter telescope, while the Europeans are thinking about a 39-meter telescope. What technological innovation allows astronomers to be thinking about telescopes with that large an aperture

The mirror in these telescopes will be constructed from many smaller mirrors which will work together.

Explanation:

A telescope is defined as an optical instrument that is used to observe or view the distant objects. A telescope is made up of curved lenses or mirrors or by combining both.

In the context, both the US and the Europeans are planning to make a telescope which is 30 m and 39 m respectively. This could be possible as the mirrors that are used to make these telescope will be made from a many smaller mirrors that will work together as a single large mirror having a very large aperture.