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Moving far backwards in time, more than 200,000 years ago Venus sometimes passed by at a distance from Earth of barely less than 38 million km, and will next do that after more than 400,000 years. Venus and Earth come the closest, but they come less often closer than Venus and Mercury . [ 10 ]
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy , it usually applies to planets or asteroids orbiting the Sun , moons orbiting planets, exoplanets orbiting other stars , or binary stars .
Consequently, Venus transits above Earth only occur when an inferior conjunction takes place during some days of June or December, the time where the orbits of Venus and Earth cross a straight line with the Sun. [185] This results in Venus transiting above Earth in a sequence of currently 8 years, 105.5 years, 8 years and 121.5 years, forming ...
In this frame of reference, Earth's rotation is close to constant, but the stars appear to rotate slowly with a period of about 25,800 years. It is also in this frame of reference that the tropical year (or solar year), the year related to Earth's seasons, represents one orbit of Earth around the Sun. The precise definition of a sidereal day is ...
During the Earth's 243 sidereal orbital periods, which total 88,757.3 days, Venus completes 395 sidereal orbital periods of 224.701 days each, which is equal to 88,756.9 Earth days. This period of time corresponds to 152 synodic periods of Venus. [2]
The full cycle from new to full to new again takes 584 days (the time it takes Venus to overtake the Earth in its orbit). Venus (like the Moon) has 4 primary phases of 146 days each. The planet also changes in apparent size from 9.9 arc seconds at full (superior conjunction) up to a maximum of 68 arc seconds at new (inferior conjunction). [1]
Rotation period days: 25.38 Orbital period about Galactic Center [4] million years 225–250 Mean orbital speed [4] km/s: ≈ 220 Axial tilt to the ecliptic: deg. 7.25 Axial tilt to the galactic plane: deg. 67.23 Mean surface temperature: K: 5,778 Mean coronal temperature [5] K: 1–2 × 10 6: Photospheric composition H, He, O, C, Fe, S
On a human time scale, these perturbations can be accounted for using numerical models, [53]: 9-6 but the planetary system can change chaotically over billions of years. [54] The angular momentum of the Solar System is a measure of the total amount of orbital and rotational momentum possessed by all its moving components. [55]