Hemera was the goddess of the Day in Greek mythology
Hemera's sister was Aether, the goddess of the Heaven. Hemera was residing with her mother in Tartarus, in the depths of the Underworld, but the two deities never met each other at home.
Shortly after the break of day, Hemera was making a journey from the land of the dawn to the land of the heavens, gradually taking the place of Eos, the goddess of the dawn. Upon arrival, Helios, the sun god, hid himself in his golden cup and night fell upon the earth, and Hemera returned to her home in the Underworld. That was the moment when her mother Nyx would start her nightly journey.