Final answer:
Galileo Galilei significantly improved the early telescope to study the lunar surface in detail, discovering features such as craters and mountains, and showing the moon to be a world similar to our own.
Step-by-step explanation:
Galileo Galilei created an improved version of the early telescope to get a closer look at the moon's surface. Although he did not invent the telescope, Galileo was the first to use it to make astronomical observations. With his enhanced telescopes, which featured increased magnification up to 30x, he was able to observe the moon in great detail, discovering its craters, mountains, and valleys. This pioneering work by Galileo showed that the moon was not just a mysterious object in the sky, but a world with geological features similar to Earth.