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Perihelion and Aphelion

The Earth is closest to the Sun, at its perihelion, about two weeks after the December solstice and farthest from the Sun, or at its aphelion, about two weeks after the June solstice.

Diagram showing the distance between the Sun and Earth at different times of the year (perihelion and aphelion).
Diagram showing the distance between the Sun and Earth at different times of the year (perihelion and aphelion).

Earth is farthest from the Sun when it is summer in the Northern Hemisphere.

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Changing Elliptical Orbit

The Earth orbits the Sun in an elliptical path, which means that there is one point on the path closest to the Sun and one point that is farthest away from the Sun.

Orbit Changes Shape

This path's shape varies due to the gravitational influences of other planetary objects, particularly the Moon. Approximately every 100,000 years, the Earth's orbital path changes from being nearly circular to elliptical. The difference of the Earth’s orbital shape from a perfect circle is known as its eccentricity. An eccentricity value of 0 is a circular orbit, while values between 0 and 1 describe an elliptical orbit.

Aphelion in Hong Kong, Hong Kong is on
Friday, 5 July 2024, 13:06 HKT (Change city)

Distance from the Sun's center to Earth's center will be 152,099,968 km (94,510,539 mi)

YearPerihelionDistanceAphelionDistance
20243 January 2024 08:38147,100,632 km5 July 2024 13:06152,099,968 km
20254 January 2025 21:28147,103,686 km4 July 2025 03:54152,087,738 km
20264 January 2026 01:15147,099,894 km7 July 2026 01:30152,087,774 km
20273 January 2027 10:32147,104,592 km5 July 2027 13:05152,100,481 km
20285 January 2028 20:28147,100,687 km4 July 2028 06:18152,093,129 km
* All aphelion/perihelion times are in local Hong Kong time.

Earth's Perihelion and Aphelion

The Earth is closest to the Sun, or at the perihelion, about two weeks after the December solstice, when it is winter in the Northern Hemisphere. Conversely, the Earth is farthest away from the Sun, at the aphelion point, two weeks after the June solstice, when the Northern Hemisphere is enjoying warm summer months.

Is the Timing a Coincidence?

Due to variations in the eccentricity of the Earth's orbit, the dates when the Earth reaches its perihelion or aphelion are not fixed. In 1246, the December Solstice was on the same day as the Earth reached its perihelion. Since then, the perihelion and aphelion dates have drifted by a day every 58 years. In the short-term, the dates can vary up to two days from one year to another.

Mathematicians and astronomers estimate that in 6430, over 4000 years from now, the perihelion will coincide with the March equinox.

Perigee and Apogee

The Moon's path around the Earth is also elliptical. The point in the Moon's orbit that is closest to the Earth is called the perigee and the point farthest from the Earth is known as the apogee. The terms are also sometimes used interchangeably with the Earth's perihelion and aphelion.

Did You Know...

...that the words perihelion and aphelion come from ancient Greek, where peri means close, apo means far, and helios means the Sun? They are used in astronomy to refer to the closest and farthest points of the orbits of any object revolving around the Sun. Together, they are called apsides—the points of least or greatest distance of a celestial object in orbit around another astronomical body.

Topics: Astronomy, Solstice, Sun, Equinox