Editing Lunar phase (section)

== Misconceptions ==
=== Orbital period ===
It can be confusing that the Moon's orbital sidereal period is 27.3 days while the phases complete a cycle once every 29.5 days (synodic period). This is due to the Earth's orbit around the Sun. The Moon orbits the Earth 13.4 times a year, but only passes between the Earth and Sun 12.4 times.

=== Eclipses ===
[[File:Eclipse vs new or full moons, annotated.svg|thumb|As the Earth revolves around the Sun, approximate [[axial parallelism]] of the Moon's orbital plane ([[Orbital inclination|tilted]] five degrees to the [[ecliptic|Earth's orbital plane]]) results in the revolution of the [[lunar nodes]] relative to the Earth. This causes an [[eclipse season]] approximately every six months, in which a [[solar eclipse]] can occur at the [[new moon]] phase and a [[lunar eclipse]] can occur at the [[full moon]] phase.]]
[[File:Orbit of the Moon in 2013.ogv|right|thumb|The ''lunar phase'' depends on the Moon's position in orbit around the Earth and the Earth's position in orbit around the Sun. This animation (''not to scale'') looks down on Earth from the north pole of the ecliptic.]]

It might be expected that once every month, when the Moon passes between Earth and the Sun during a new moon, its shadow would fall on Earth causing a [[solar eclipse]], but this does not happen every month. Nor is it true that during every full moon, the [[Earth's shadow]] falls on the Moon, causing a [[lunar eclipse]]. Solar and lunar eclipses are not observed ''every'' month because the plane of the [[Moon's orbit]] around the Earth is tilted by about 5° with respect to the plane of [[Earth's orbit]] around the Sun (the plane of the [[ecliptic]]). Thus, when new and full moons occur, the Moon usually lies to the north or south of a direct line through the Earth and Sun. Although an [[eclipse]] can only occur when the Moon is either new (solar) or full (lunar), it must also be positioned very near the intersection of Earth's orbital plane about the Sun and the Moon's orbital plane about the Earth (that is, at one of [[lunar node|its nodes]]). This happens about twice per year, and so there are between four and seven eclipses in a calendar year. Most of these eclipses are partial; total eclipses of the Moon or Sun are less frequent.

=== Mechanism ===
The phases are not caused by the Earth's shadow falling on the moon, as some people believe.<ref>{{Cite news |last1=Musgrave |first1=Ian |last2=Weule |first2=Genelle |date=January 29, 2018 |title=A beginner's guide to the Moon |url=https://www.abc.net.au/news/science/2018-01-24/beginners-guide-to-the-moon/9320770 |access-date=June 29, 2024 |work=[[Australian Broadcasting Corporation]]}}</ref><ref>{{Cite news |last=Plait |first=Phil |date=December 28, 2012 |title=Today's Full Moon is the 13th and Last of 2012 |url=https://slate.com/technology/2012/12/full-moon-today-is-the-13th-full-moon-of-2012.html |access-date=June 29, 2024 |work=[[Slate (magazine)|Slate]]}}</ref> They are caused by the moon's shadow on itself, just as the Earth's shadow makes it night on one side of the Earth. The angle of the Sun in relation to the Moon determines how much of the Moon is illuminated.