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The six Earth images are positions along the orbital ellipse, which are sequentially the perihelion (periapsis—nearest point to the Sun) on anywhere from January 2 to January 5, the point of March equinox on March 19, 20, or 21, the point of June solstice on June 20, 21, or 22, the aphelion (apoapsis—the farthest point from the Sun) on ...
At perihelion, Earth is roughly 91.4 million miles away from the sun. On average, the planet is separated from the sun by a distance of approximately 93 million miles.
The Earth spends less time near perihelion and more time near aphelion. This means that the lengths of the seasons vary. [15] Perihelion currently occurs around 3 January, so the Earth's greater velocity shortens winter and autumn in the northern hemisphere, and summer and spring in the southern hemisphere.
The apsides refer to the farthest (2) and nearest (3) points reached by an orbiting planetary body (2 and 3) with respect to a primary, or host, body (1). An apsis (from Ancient Greek ἁψίς (hapsís) 'arch, vault'; pl. apsides / ˈ æ p s ɪ ˌ d iː z / AP-sih-deez) [1] [2] is the farthest or nearest point in the orbit of a planetary body about its primary body.
As the two dates chosen here are equinoxes, this will be correct when perihelion, the date the Earth is closest to the Sun, falls on a solstice. The current perihelion, near January 4, is fairly close to the solstice of December 21 or 22.
Earth's rotation period relative to the Sun (solar noon to solar noon) is its true solar day or apparent solar day. [26] It depends on Earth's orbital motion and is thus affected by changes in the eccentricity and inclination of Earth's orbit. Both vary over thousands of years, so the annual variation of the true solar day also varies.
Earth's rotational velocity also varies in a phenomenon known as length-of-day variation. [171] Earth's annual orbit is elliptical rather than circular, and its closest approach to the Sun is called perihelion. In modern times, Earth's perihelion occurs around 3 January, and its aphelion around 4 July.
Previous perihelion passages were in 1986, 2061, 2134, and 2209. 2287 C/1979 Y1 (Bradfield) (suspected source of the July Pegasids) is expected to come to perihelion. [66] 2287 August 28 Closest perihelic opposition of Mars and Earth since August 27, 2003, at 55,688,405 km (34,603,170.6 mi; 0.372254 AU). 2288