The longest day
Posted 21st Jun 2021
Happy summer equinox 2021!
Summer is officially here in the northern hemisphere with the summer solstice occurring on Monday 21 June at 4.32am BST.
On this ‘longest day’ the number of hours of sunlight are at their maximum with the exact moment of the summer solstice occurring when the hemisphere of the earth you are in is most tilted towards the sun.
The axis of rotation of the Earth is not lined up with the axis of motion around the Sun. Instead, it is tilted slightly at 23.44° hence creating variation in the length of day. Our tellurium gearing maintains this exact tilt of the Earth’s axis and as such is the perfect astronomy teaching aid to accurately demonstrate and explain why today is the longest day for some – and the shortest for others.