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  2. Earth's orbit - Wikipedia

    en.wikipedia.org/wiki/Earth's_orbit

    As seen from Earth, the planet's orbital prograde motion makes the Sun appear to move with respect to other stars at a rate of about 1° eastward per solar day (or a Sun or Moon diameter every 12 hours). [nb 1] Earth's orbital speed averages 29.78 km/s (19 mi/s; 107,208 km/h; 66,616 mph), which is fast enough to cover the planet's diameter in 7 ...

  3. Ecliptic - Wikipedia

    en.wikipedia.org/wiki/Ecliptic

    This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth did not orbit; a day on Earth is therefore 24 hours long rather than the approximately 23-hour 56-minute sidereal day ...

  4. Orbital period - Wikipedia

    en.wikipedia.org/wiki/Orbital_period

    In common usage, these two objects are typically Earth and the Sun. The time between two successive oppositions or two successive conjunctions is also equal to the synodic period. For celestial bodies in the solar system, the synodic period (with respect to Earth and the Sun) differs from the tropical period owing to Earth's motion around the Sun.

  5. Kepler's laws of planetary motion - Wikipedia

    en.wikipedia.org/wiki/Kepler's_laws_of_planetary...

    The orbits are ellipses, with foci F 1 and F 2 for Planet 1, and F 1 and F 3 for Planet 2. The Sun is at F 1.; The shaded areas A 1 and A 2 are equal, and are swept out in equal times by Planet 1's orbit.

  6. Analemma - Wikipedia

    en.wikipedia.org/wiki/Analemma

    Afternoon analemma photo taken in 1998–99 in Murray Hill, New Jersey, U.S., by Jack Fishburn.The Bell Laboratories building is in the foreground. In astronomy, an analemma (/ ˌ æ n ə ˈ l ɛ m ə /; from Ancient Greek ἀνάλημμα (analēmma) 'support') [a] is a diagram showing the position of the Sun in the sky as seen from a fixed location on Earth at the same mean solar time over ...

  7. Equation of time - Wikipedia

    en.wikipedia.org/wiki/Equation_of_time

    But the orbit of the Earth is an ellipse not centered on the Sun, and its speed varies between 30.287 and 29.291 km/s, according to Kepler's laws of planetary motion, and its angular speed also varies, and thus the Sun appears to move faster (relative to the background stars) at perihelion (currently around 3 January) and slower at aphelion a ...

  8. NASA is about to 'touch' the sun. Here's what you need to know.

    www.aol.com/nasa-touch-sun-heres-know-002030206.html

    NASA's Parker Solar Probe launched in 2018 and has completed 21 close flybys around the sun. However, its mission on Christmas Eve will be unlike any other. ... Yes, 3.8 million miles is far by ...

  9. Milankovitch cycles - Wikipedia

    en.wikipedia.org/wiki/Milankovitch_cycles

    The Earth's orbit approximates an ellipse. Eccentricity measures the departure of this ellipse from circularity. The shape of the Earth's orbit varies between nearly circular (theoretically the eccentricity can hit zero) and mildly elliptical (highest eccentricity was 0.0679 in the last 250 million years). [6] Its geometric or logarithmic mean ...