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The Sun's gravitational effect on the Moon is more than twice that of Earth's on the Moon; consequently, the Moon's trajectory is always convex [25] [26] (as seen when looking Sunward at the entire Sun–Earth–Moon system from a great distance outside Earth–Moon solar orbit), and is nowhere concave (from the same perspective) or looped.
In effect, this means that the "tropical year" on the Moon is only 347 days long. This is called the draconic year (or eclipse year). The "seasons" on the Moon fit into this period. For about half of this draconic year, the Sun is north of the lunar equator (but at most 1.543°), and for the other half, it is south of the lunar equator.
Since this value is close to zero, the center of 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 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).
The Sun is, by definition, always seen on the ecliptic (the Sun's apparent path across the sky) while Earth is tilted at an angle of e = 23.5° to the plane of that path and completes one orbit around the Sun in 365.25636 days, slightly longer than one year due to precession altering the direction of Earth's inclination.
The Moon is Earth's only natural satellite.It orbits at an average distance of 384,400 km (238,900 mi), about 30 times the diameter of Earth. Tidal forces between Earth and the Moon have synchronized the Moon's orbital period (lunar month) with its rotation period at 29.5 Earth days, causing the same side of the Moon to always face Earth.
For example, the synodic period of the Moon's orbit as seen from Earth, relative to the Sun, is 29.5 mean solar days, since the Moon's phase and position relative to the Sun and Earth repeats after this period. This is longer than the sidereal period of its orbit around Earth, which is 27.3 mean solar days, owing to the motion of Earth around ...
Orion capsule of Artemis 1 above the Moon in December 2022. In astronomy and spaceflight, a lunar orbit (also known as a selenocentric orbit) is an orbit by an object around Earth's Moon. In general these orbits are not circular. When farthest from the Moon (at apoapsis) a spacecraft is said to be at apolune, apocynthion, or aposelene.
Since the Moon's axial tilt is only 1.5° with respect to the ecliptic (the plane of Earth's orbit around the Sun), this effect is small. Once every 18.6 years, [ 1 ] the lunar north pole describes a small circle around a point in the constellation Draco , while correspondingly, the lunar south pole describes a small circle around a point in ...