Search results

Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is...

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...

and set in the west due to the rotation of Earth, so do the stars. Both solar time and sidereal time make use of the regularity of Earth's rotation about...

the orbit is relatively close to the center of the Sun (relative to the size of the orbit). As seen from Earth, the planet's orbital prograde motion makes...

rotates over time. This orbital precession is called apsidal precession and is the rotation of the Moon's orbit within the orbital plane, i.e. the axes of...

closely orbiting binaries are expected to be tidally locked,[citation needed] as well as contact binaries. Earth's Moon's rotation and orbital periods...

orbit), e.g. Earth's orbit around the Sun. The ends of the external axis of revolution can be called the orbital poles. Either type of rotation is involved...

above Earth's equator, 42,164 km (26,199 mi) in radius from Earth's center, and following the direction of Earth's rotation. An object in such an orbit has...

Moon to a higher orbit with a lower orbital speed). Secondly, there is an apparent increase in the Moon's angular rate of orbital motion (when measured...

the year because the Earth's orbit is not perfectly circular and because its rotational axis is not perpendicular to its orbital plane. One mean solar...

apparent retrograde motion. A person standing on Earth "catches up" to the Moon and passes it because the Earth completes one rotation before the Moon completes...

centre of mass, while the orbital angular momentum is the angular momentum about a chosen center of rotation. The Earth has an orbital angular momentum by nature...

down Earth's angular velocity ω. Due to the conservation of angular momentum, this process transfers angular momentum to the Moon's orbital motion, increasing...

is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle...

gamma-ray bursts and detectable gravitational waves. Orbital decay is caused by one or more mechanisms which absorb energy from the orbital motion, such as fluid...

points in the orbit of maximum axial tilt toward or away from the Sun—and the equinoxes, when Earth's rotational axis is aligned with its orbital axis. In...

angular orbital velocity equals its angular rotational velocity so that the Sun's apparent motion ceases; closer to perihelion, Mercury's angular orbital velocity...

orbit matches the Earth's rotational period, but the definition does not require it to have zero orbital inclination to the equator, and thus is not stationary...

slow, and continuous change in the orientation of an astronomical body's rotational axis. In the absence of precession, the astronomical body's orbit would...

amount due to the orbital motion of Earth around the Sun. Note that astrophysical literature does not typically use the equatorial rotation period, but instead...