What is the Moon’s “Syzygy”?

14 August 2014

The Short Answer (TSA)

            Actually, the Moon, alone, can’t have “syzygy.” In astronomy, the word syzygy requires at least 3 “celestial bodies” positioned in a straight line.

            So, at the Full Moon, the Earth is exactly between the Sun and Moon.  Viewed from space, the 3, Sun, Earth and Moon, would appear to form a straight line.  And this is called a syzygy.  At the New Moon, the Moon is exactly between the Sun and Earth.  Again, if you could see the 3, Sun, Moon and Earth, from a point out in space, they would appear to form a straight line.  And, again, this is another syzygy.

            Sometimes the word syzygy is misused to describe an alignment of 3 or more planets in our solar system.  For example, the conjunction of (all in the same place in the sky) Venus, Mars and Jupiter, might is sometimes be called a syzygy.

            But to be a true syzygy, the alignment must have gravitational effects within the system.  Most obvious are the gravitational effects of New and Full Moon syzygies on the ocean tides.  Formal scientific study reportedly shows that the positions of the Sun and Moon do not affect earthquake or volcanic activity on the Earth.  But it is known that New and Full Moons cause gravitational stress on the Moon and trigger “moonquakes.”

M Grossmann of Hazelwood, Missouri
(& Belleville, Illinois)
About the Author
14 August 2014