Editing 1878: Earth Orbital Diagram

The comic claims that the reason that eclipses don't happen every month is simple to understand by looking at an orbital diagram. Ironically, the cartoon has so many parts and labels which make it far more difficult to understand than is implied. While the graph itself is based {{w|Orbital elements|astronomical definitions}} all the labels are nonsense in this context.

All these labels are complicated words, some are somewhat related to orbital mechanics ("equinox", "perihelion") while some are just latin sounding nouns. Moreover, many of the labels provided are kludged, obfuscated, or simply made up. Compare/contrast with the standard {{w|Kepler orbit|Kepler Orbit}} diagram.  Most easily recognizable are the "Dimples of Venus," referring to axis-intersection points in the diagram on Earth.  

The title text refers to 'orbit' being also the anatomical term for the eyesocket.

{| class=wikitable

! Word used in the comics

! Actual astronomical term

! Meaning of actual term

 

| {{w|Arctangent}}

|  

|  

| {{w|Astral plane}}

|

|

 

| {{w|Declension}}

| Inclination

| The "tilt" of an orbit

 

| {{w|Dimples of Venus}}

| Belt of Venus

| Shadow cast by the Earth visible in its atmosphere

 

| {{w|Enceliopsis}}

| Small genus of flowering plants in the daisy family, appropriately known as "sunrays"

| The plane in which the Sun appears to orbit around the Earth - and, accordingly, the plane in which the Earth orbits around the Sun

| {{w|Errata}}

| Errata are a list of errors and corrections to published texts.

| {{w|Hypothecate}}

| A legal verb that means something similar to "make a mortgage"

|

|

| {{w|Obsequity}}

| The state of being obsequious (showing a willingness to obey or serve)

| Perihelix

| Portmanteau of helix and perihelion

| Perihelion

| Lowest point in a solar orbit

| {{w|Prolapse}}

| A medical condition where an internal organ to move out of place

| The plane in of the Earth's orbit about the Sun

| {{w|Solar plexus}}

| Network of nerves located in the abdomen.

| Star in our solar system.

|-

| {{w|Tropopause}}

| The boundary in our atmosphere between the troposphere and stratosphere.  It is defined as the boundary where air ceases to cool with elevation.

|}

If the plane of where the Earth orbits the Sun and where the Moon orbits the Earth were completely aligned, then there would be a solar eclipse at every New Moon (once every [https://en.wikipedia.org/wiki/Orbit_of_the_Moon#Lunar_periods 29.5 days]) and a lunar eclipse at every full moon (half a lunar period about 14.7 days after a New Moon).  However, the plane in which the Moon orbits the Earth is tilted with an inclination of 5 degrees relative to that of the ecliptic plane (the plane defined by the Earth's orbit around the Sun).  Eclipses are only possible during two eclipse seasons each year (half a year apart) where for a period of 31 to 37 days the Sun is nearly aligned with the two points in the tilted Earth-Moon plane where the Moon crosses the ecliptic plane.  During an eclipse season at the time of a new moon there will be solar eclipses visible from certain locations and during full moons there will be lunar eclipses.

The real explanation of eclipses is evident from this xkcd comic, but is labeled with a fictional character similar to a Greek Phi but with two vertical lines; the remaining labels also do not contribute to this explanation and exist only to distract or misinform the reader.

 

:[The plane of the Moon is pictured in a small angle to the Earth's plane and named Astral Plane. The angel is presented between two lines (Greek Nu or Gamma and a double Greek Chi) and identified by a character that looks similar to a Greek Phi but with two vertical lines.]