Who first observed the phases of Venus? Astronomy 1 Answer Oscar L. Apr 17, 2016 Galileo first observed the phases of Venus. Galileo saw the phases despite the planet not traversing the night sky like our Moon, thus proving that Venus orbits the Sun not the Earth. Explanation: See here for more details: https://en.wikipedia.org/wiki/Phases_of_Venus Answer link Related questions How do I determine the molecular shape of a molecule? What is the lewis structure for co2? What is the lewis structure for hcn? How is vsepr used to classify molecules? What are the units used for the ideal gas law? How does Charle's law relate to breathing? What is the ideal gas law constant? How do you calculate the ideal gas law constant? How do you find density in the ideal gas law? Does ideal gas law apply to liquids? Impact of this question 1317 views around the world You can reuse this answer Creative Commons License