There are a few things we can all agree are true.
The sun is yellow.
The sun rises in the east and sets in the west.
The sun is directly overhead at noon.
The moon comes out at night.
The North Star is the brightest star in the nighttime sky.
A compass needle points north.
Heavy objects fall faster than light objects.
The shortest distance between two points is always a straight line.
Days get shorter in winter and longer in summer.
There is no gravity in outer space.
But all of those things are FALSE, so we'll have to agree on something else.