Sources

Greeks
Library of Congress. “Ancient Greek Astronomy and Cosmology.” The Library of Congress, 2015, www.loc.gov/collections/finding-our-place-in-the-cosmos-with-carl-sagan/articles-and-essays/modeling-the-cosmos/ancient-greek-astronomy-and-cosmology. Source

Mayans
Davies, Diane. “The Maya Calendar Explained.” Maya Archaeologist - Dr Diane Davies, 2017, www.mayaarchaeologist.co.uk/public-resources/maya-world/maya-calendar-system/. Accessed 24 Sept. 2025. Source
“Maya Astronomy.” Ircamera.as.arizona.edu, ircamera.as.arizona.edu/NatSci102/NatSci102/text/extmayaastronomy.htm. Accessed 23 Sept. 2025. Source

Renaissance
Williams, Matthew. “What Did Galileo Invent?” Universe Today, 2015, www.universetoday.com/articles/galileo-inventions. Source

Astronauts
NASA. “National Aeronautics and Space Administration.” NASA, NASA, 2025, www.nasa.gov/. Source