Tropical Year

• The Tropical Year, also known as the Solar Year, is the time taken for the Sun to return to the same position after the cycle of Seasons is complete.
• For example, from one Summer Solstice until the next Summer Solstice.

The Difference between a Sidereal and a Tropical Year

• The Sidereal Year
  • This is the time taken for the Earth to complete one full orbit around the Sun, in relation to the fixed stars.
• The Tropical Year
  • The time taken to return to the same position in the cycle of Seasons, for example, from one Summer Solstice to another Summer Solstice.
• Precession of the Equinoxes
  • However, due to the Precession of the Equinoxes, discovered by Hipparchus (c.190-120 BCE), the Tropical Year is 20 minutes shorter than the Sidereal Year.