A: Edwin Hubble had access to many powerful telescopes and tools to observe more objects in space. B: In the early 1500s, Nicolaus Copernicus was the first to show that Earth was an object orbiting the sun.

C: In the early 1600s, Galileo Galilei used a basic telescope to show that the Milky Way was made up of countless stars.

D: William Herschel did not realize that large portions of the galaxy were hidden by gas and dust, so he could not identify the true shape.