Footnote

a Why is it called the Hubble telescope? It is named after the famous American astronomer Edwin Powell Hubble (1889-1953), who gave scientists a greater insight into what are now known as galaxies. What does it look like? The flying telescope is about the size of a railroad tank car or a four-​story tower, being about 44 feet [13 m] long and 14 feet [4 m] in diameter, and it weighed just over 12 tons at launch.