Flat-earthers usually claim that gravity does not exist.  It is claimed to be incompatible with how things fly.  If gravity makes things fall down everything is supposed to always fall down.  (As if gravity was the only force relevant in the context.)  Or things are believed to only be influenced by gravity when in contact with the ground.  In reality everything is affected more or less by gravity without needing touch.

To understand how things fly ones has to understand how the round Earth affects water and air.  Even without consideration of land and sea the Earth is not a perfect sphere.  It is a little flattened at the poles and protrudes a little at the Equator.  The difference in the Earth’s radius is a little more than 21 kilometres (13 miles).  Water follows the roundness of the Earth and as such the oval shape.  In addition, there are small differences in the Earth’s internal density.  These create additional differences which are less than one tenth as large.  The result is a somewhat uneven ball which at sea correspond to the sea surface.  Sea level is thus not flat however, small areas may seem that.  Height above sea level is measured based on this.

In contrast with the sea surface air has no sharp boundary to space.  Instead, it gradually sparse out until the amount of air becomes negligible.  Please note this is about height above sea level.  This makes the air thinner the further up mountains one gets.  Everything flying are dependant of there being enough air for the object or being to fly in.  They move in relation to the air which in turn moves in relation to the ground.  This is why aircrafts don’t automatically fly out into space.  Not only are they affected by gravity which holds on the air to the Earth.  They also have an upper limit to how thin air they can fly in.

Moreover, one has to think about how things keep themselves airborne.  It is only balloons and airships which can keep themselves airborne thanks to their low density.  Gliding extends a fall and can utilize the air’s own movements.  But it is a limited method to keep oneself airborne.  Animals need to flutter their wings to hold against gravity.  The same principle is used by helicopters and similar aircrafts.  Airplanes can keep themselves airborne thanks to their high speed.  If all engines stopped working the plane would glide down.  Which has in fact happened sometimes.

When one thinks about how air moves one has to think in three dimensions.  Why would it not be possible for wind to blow in different directions at different heights above the ground?  If the wind only blew from one place the air there would disappear.  Other air naturally takes its place.  Why would it not do this in height but only at the sides?  Reality is not limited by what certain individuals can imagine.

Uploaded on the 25th of October 2023.