2016  2017 2018  2019  2020  2021  2022  2023  2024  2025  2026 ….


  • calendar year is roughly the time; Earth takes to travel once around our Sun – 365 days.
  • our Earth actually takes 365.24219 (365¼) days to orbit our Sun -this is called a solar year.
  • compensating for the missing 0.242 days (¼ day) -adds an extra day in February every fourth year – this is called leap year. (¼ day + ¼day + ¼day + ¼day = 1 day extra every four years)
  • when measured by the stars – not our Sun, Earth takes 365.25636 days to go round our Sun – this is because our Sun also moves a little, relative to the stars; this is called sidereal year.

Measuring the stars

Earth’s perihelion and aphelion

Earth’s perihelion

  • our Earth’s perihelion is the day its orbit brings it closest to the Sun – 3rd January.

Earth’s aphelion

  • our Earth’s aphelion is the day it is furthest from the Sun – 4th July.

The Orbit of the Planets

  • Mercury
    – the planet with the shortest year is Mercury around the Sun in just 88 days.
  • Venus
    – the second closest planet to our Sun, Venus completes a single orbit once ever 224.7 days.
  • Earth
    – it takes 365.2564 solar days to complete a single orbit of the Sun.
    – which is why we add an extra day to the calendar every four years (leap year).
  • Mars
    – one of the highest eccentricities of any planet in the Solar System.
    – ranging from 128,437,425 miles at perihelion and 154,845,701 miles at aphelion
    – takes the equivalent of 687 (Earth) days or 1.8 calendar year to complete a single orbit around the Sun.
  • Jupiter
    – another interesting case
    – whereas the gas giant only takes 9 hours 55 minutes and 30 seconds to rotate once on its axis.
    – also takes alson 11.8618 Earth years to complete an orbit around the Sun.
  • Saturn
    – much like its fellow gas giant Jupiter, Saturn takes it time completing a single orbit of the Sun.
    – rotates on its axis very rapidly.
    – a year on the planet lasts the equivalent of 10,759 Earth days (or about 29½ years).
    – since it only takes 10 hours, and 33 minutes to complete a single rotation on its axis.
  • Uranus
    – the gas/ice giant takes about 84 Earth years (or 30,688.5 Earth days) to rotate once around the Sun.
    – since the planet takes 17 hours, 14 minutes and 24 seconds to complete a single rotation on its axis.
    – a year on Uranus lasts 42,718
     Uranian days.
  • Neptune
    – the planet with the longest year
    – takes 164.8 years to orbit the Sun.
    – lasting the equivalent of 164.8 years (or 60,182 Earth days).
    – since Neptune also takes comparatively little time to rotate once on its axis (16 hours, 6 minutes and 36 seconds).
    – a single year lasts a staggering 89,666 Neptunian days.


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