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  2. Earth's orbit - Wikipedia

    en.wikipedia.org/wiki/Earth's_orbit

    One complete orbit takes 365.256 days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi). [2] Ignoring the influence of other Solar System bodies, Earth's orbit, also called Earth's revolution, is an ellipse with the Earth–Sun barycenter as one focus with a current eccentricity of 0.0167. Since this value ...

  3. Earth's rotation - Wikipedia

    en.wikipedia.org/wiki/Earth's_rotation

    Earth's rotation. Earth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space. Earth rotates eastward, in prograde motion. As viewed from the northern polar star Polaris, Earth turns counterclockwise. The North Pole, also known as the Geographic North ...

  4. Axial precession - Wikipedia

    en.wikipedia.org/wiki/Axial_precession

    The stars viewed from Earth are seen to proceed from east to west daily, due to the Earth's diurnal motion, and yearly, due to the Earth's revolution around the Sun. At the same time the stars can be observed to anticipate slightly such motion, at the rate of approximately 50 arc seconds per year, a phenomenon known as the "precession of the ...

  5. Equatorial bulge - Wikipedia

    en.wikipedia.org/wiki/Equatorial_bulge

    The Earth's rotation rate is still slowing down, though gradually, by about two thousandths of a second per rotation every 100 years. [1] Estimates of how fast the Earth was rotating in the past vary, because it is not known exactly how the moon was formed. Estimates of the Earth's rotation 500 million years ago are around 20 modern hours per ...

  6. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    An increase of 360° in the ERA is a full rotation of the Earth. A sidereal day on Earth is approximately 86164.0905 seconds (23 h 56 min 4.0905 s or 23.9344696 h). (Seconds are defined as per International System of Units and are not to be confused with ephemeris seconds.)

  7. Earth - Wikipedia

    en.wikipedia.org/wiki/Earth

    Earth is rounded into an ellipsoid with a circumference of about 40,000 km. It is the densest planet in the Solar System. Of the four rocky planets, it is the largest and most massive. Earth is about eight light-minutes away from the Sun and orbits it, taking a year (about 365.25 days) to complete one revolution.

  8. Coriolis frequency - Wikipedia

    en.wikipedia.org/wiki/Coriolis_frequency

    The Coriolis frequency ƒ, also called the Coriolis parameter or Coriolis coefficient, [1] is equal to twice the rotation rate Ω of the Earth multiplied by the sine of the latitude . The rotation rate of the Earth (Ω = 7.2921 × 10 −5 rad/s) can be calculated as 2 π / T radians per second, where T is the rotation period of the Earth which ...

  9. Orbit of the Moon - Wikipedia

    en.wikipedia.org/wiki/Orbit_of_the_Moon

    Every 18.6 years, the angle between the Moon's orbit and Earth's equator reaches a maximum of 28°36′, the sum of Earth's equatorial tilt (23°27′) and the Moon's orbital inclination (5°09′) to the ecliptic. This is called major lunar standstill. Around this time, the Moon's declination will vary from −28°36′ to +28°36′.