Are you a fan of the musical Cats? Towards the end of there is a scene where the old female Grizabella is chosen to ascend to the Heaviside layer by Old Deuteronomy. Based on a book of poems called “Old Possum’s Book of Practical Cats” by T.S. Elliot, you might think the Heaviside layer is as made-up as his jellicle cats and pollicle dogs – but it actually exists.
Formally known as the Kennelly-Heaviside layer, it is part of the ionopshere between 90-150 km above the surface. It is named after the two men who simultaneously predicted it’s existence in 1902, Arthur E. Kennelly and Oliver Heaviside, but it’s existence wasn’t proven until 1924, which won Edward Appleton the 1947 Nobel Prize in Physics.
It’s height is affected by the strength of the solar wind, being pushed down on the sunward-side and pulled away on the night-side of the Earth. This can sometimes lead to some very interesting effects with regard to the distance that radio waves can travel.
But for now, let us watch Grizabella as she passes by the Russell Hotel and heads on past the Jellicle Moon to the Heaviside layer for cats.