Flat-earthers show great ignorance about the movements of celestial bodies.  It is bad enough to believe that perspective could explain the sun rising and setting.  Worse is mystifying the movements of the moon and ascribe to it mysterious properties.  Not to talk about the stars which they seem to entirely lack awareness of.

I am likely more aware of what happens in nature than many other Westerners.  One thing I have thought about in this context is how much the daylight varies.  Now I live in Märsta where this varies greatly over the year.  I have also travelled a lot all over Europe in the summers.  Then I have noticed the time with daylight to vary by latitude.  The further one gets northward the longer is the time with daylight.  Would this only apply in summer and not the opposite in winter?  I don’t think it works like that.

My own experience as such makes me trust the most common explanation.  The time of the rising and setting of the sun varies symmetrically over the year.  What little asymmetry I know about is due to refraction near the horizon.  The result is that both midnight sun and polar night occurs at both poles.  When one polar region has midnight sun the other one has polar night and the opposite.  Please note that it is only at the polar circles which it happens once a year.  The closer to the poles themselves ones comes the longer the period gets without sunset or sunrise.  When one reaches the pole itself the sun only rises and sets once.  At about the time when the sun rises on the North Pole it sets on the South Pole.  I don’t know if this is on the same date.  However, if this is not the case, I think it is within a couple of days of each other.

People tend to associate the moon with the night.  But the moon is only up half the time the sun is down.  On the other hand, it is possible in some cases to see the moon in daylight.  If the moon is at least a quarter it is also visible when the sun is up.  Otherwise, it shines too weakly for us to discern it.  Still the movements of the moon could already be documented by early state societies.  This eventually led to them being able to predict solar eclipses.  By then it was clear solar eclipses are caused by the moon passing in front of the sun.  Those denying this today know too little about the movements of the moon.

At least some flat-earthers denies that moonlight is reflected sunlight.  They claim moonlight cools while sunlight heats.  Therefore, they would be essentially different.  It seems to require magical thinking for one to believe something like that.  To me it appears completely plausible that moonlight is sunlight reflected on what in principle is a dark grey rock.  Such light is not bright enough to cause any noticeable temperature increase.  In contrast, nights with moonlight are colder because they have less cloud cover.  Clear nights are cold nights regardless if the moon is visible or not.

Many flat-earthers also denies there any differences between stars and planets.  Trouble is one can see the difference between the two with an unaided eye.  Planets shine noticeably brighter and don’t twinkle like the stars.  If one checks them out night after night they move against the background of stars.  This way five of the planets become already known before the invention of writing.

In addition, the stars move over the sky during the night too.  North of the equator they look like they revolve around a point near Polaris.  South of the equator they look like they revolve around a point having no bright stars nearby.  If one is close to the equator, it looks like they revolve around two points.  I don’t know how near the equator one need to be for this.  Anyway, this means stars also rise and set.  Moreover, there is a difference in what stars one can see at different times of the year.  Certainly, there are constellations one can see at entirely different times of the year.  However, this does not mean all constellations particularly not near the equator.  If one is on the very equator all stars one can see are replaced over half a year.

Interestingly, it was the differences in background stars which established the idea of a round Earth.  This was Aristoteles’ argument for the Earth being round.  There being differences in which stars one sees at different latitudes.  Even the difference between Giza and Thessaloniki must have been noticeable to sailors.  So the Greeks developed a method for finding out one’s latitude based on the height of certain stars.  Methods developed from it can still be used today.  But they are not needed as often anymore.

In summary the movements of the celestial bodies are incompatible with a flat Earth.  Either celestial bodies are nowhere near where in the sky we see them.  Or we have to accept the consequence that the Earth has to be round.  Some flat-earthers have suggested each of us see his or her own sky.  Trouble is, two people standing beside each other in an open area usually see the same thing.  The most important exception is if one of them has noticeably poorer eyesight.  This person will then miss some of what the other person sees.  Otherwise, one can presuppose they see the same things in the sky.  This makes it possible to learn to navigate by the stars.  Something people have done for millennia.

Uploaded on the 17th of October 2023.