What is aphelion

Distance to the sun: perihelion and aphelion

Perihelion and aphelion

The orbit of the earth around the sun is not circular, but elliptical (oval). This means that the distance between the earth and the sun is constantly changing.

  • Perihelion: Point of orbit at which the earth is the sun the next is.
  • Aphelion: Point of orbit where the earth is the furthest away from the sun.

What do perigee and apogee mean?

Upcoming dates

Aphelion in Berlin, Berlin, Germany:
Tuesday, July 6, 2021, 12:27 AM CEST (change city)

Distance from earth to sun (center point): 152 100 527 km (94 510 886 mi)

yearPeriheliondistanceApheliondistance
2021January 2, 2021 2:50 pm147 093 163 kmJuly 6, 2021 12:27 AM152 100 527 km
2022January 4, 2022 7:52 AM147 105 052 kmJuly 4, 2022 9:10 AM152 098 455 km
2023January 4, 2023 5:17 PM147 098 925 kmJuly 6, 2023 10:06 PM152 093 251 km
2024January 3, 2024 1:38 am147 100 632 kmJuly 5, 2024 7:06 AM152 099 968 km
2025January 4, 2025 2:28 PM147 103 686 kmJuly 3, 2025 9:54 pm152 087 738 km

Distance to the sun on a date of your choice

Orbit is deforming

The orbit of the earth is deformed every 100,000 years by the action of other planets from an almost perfect circle to an ellipse. At the moment their deviation from a circle is (eccentricity) with 0.0167 quite low - with the naked eye such an ellipse cannot be distinguished from a circle.

Because of the enormous size of the orbit, this relatively small deviation means that the distance between the earth and the sun fluctuates by around 5 million kilometers over the course of the year.

Longitudes and latitudes explained

Distance greatest in summer

Contrary to popular belief, the distance to the sun has very little effect on the seasons. Rather, spring, summer, autumn and winter are caused by the inclination of the earth's axis and the resulting fluctuating angle of incidence of sunlight over the course of the year.

Nevertheless, perihelion and aphelion seem to be related to the solstices: The earth reaches the point furthest from the sun about two weeks after the solstice in June - in the middle of summer in the northern hemisphere. The distance to the sun is smallest around two weeks after the solstice in December.

Elliptical earth orbit makes sundials inaccurate

How fast is the earth?

Appointment fluctuates

However, this temporal coincidence is a coincidence, and it changes over the centuries as the earth's orbit gradually deforms. In 1246, the earth reached perihelion on the day of the solstice in December. Since then, perihelion and aphelion dates have shifted about one day every 58 years. Perihelion is expected to fall on the March equinox day in 6430.

In addition to these long-term changes, perihelion and aphelion data can fluctuate by up to two days each year.

Most days are longer than 24 hours

Subjects: Sun, seasons, earth, solar system, astronomy