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  2. Magnetic braking (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Magnetic_braking_(astronomy)

    One possible explanation for the braking is the interaction of the protostar's magnetic field with the stellar wind. In the case of the Solar System, when the planets' angular momenta are compared to the Sun's own, the Sun has less than 1% of its supposed angular momentum. In other words, the Sun has slowed down its spin while the planets have not.

  3. Newton's theorem of revolving orbits - Wikipedia

    en.wikipedia.org/wiki/Newton's_theorem_of...

    The blue planet feels only an inverse-square force and moves on an ellipse (k = 1). The green planet moves angularly three times as fast as the blue planet (k = 3); it completes three orbits for every orbit of the blue planet. The red planet illustrates purely radial motion with no angular motion (k = 0).

  4. Differential rotation - Wikipedia

    en.wikipedia.org/wiki/Differential_rotation

    Stars and planets rotate in the first place because conservation of angular momentum turns random drifting of parts of the molecular cloud that they form from into rotating motion as they coalesce. Given this average rotation of the whole body, internal differential rotation is caused by convection in stars which is a movement of mass, due to ...

  5. Exoplanet orbital and physical parameters - Wikipedia

    en.wikipedia.org/wiki/Exoplanet_orbital_and...

    The last few giant impacts during planetary formation tend to be the main determiner of a terrestrial planet's rotation rate. On average the spin angular velocity will be about 70% of the velocity that would cause the planet to break up and fly apart; the natural outcome of planetary embryo impacts at speeds slightly larger than escape velocity.

  6. Celestial mechanics - Wikipedia

    en.wikipedia.org/wiki/Celestial_mechanics

    The common noun ‘moon’ (not capitalized) is used to mean any natural satellite of the other planets. Tidal force is the combination of out-of-balance forces and accelerations of (mostly) solid bodies that raises tides in bodies of liquid (oceans), atmospheres, and strains planets' and satellites' crusts.

  7. Kepler's laws of planetary motion - Wikipedia

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

    Newton defined the force acting on a planet to be the product of its mass and the acceleration (see Newton's laws of motion). So: Every planet is attracted towards the Sun. The force acting on a planet is directly proportional to the mass of the planet and is inversely proportional to the square of its distance from the Sun.

  8. Tidal locking - Wikipedia

    en.wikipedia.org/wiki/Tidal_locking

    In Mercury's case, the planet completes three rotations for every two revolutions around the Sun, a 3:2 spin–orbit resonance. In the special case where an orbit is nearly circular and the body's rotation axis is not significantly tilted, such as the Moon, tidal locking results in the same hemisphere of the revolving object constantly facing ...

  9. Rotation period (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Rotation_period_(astronomy)

    In astronomy, the rotation period or spin period [1] of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the sidereal rotation period (or sidereal day ), i.e., the time that the object takes to complete a full rotation around its axis relative to the background stars ( inertial space ).