Scientists Detect Earth's Atmosphere 'Ringing' Like a Bell
Just as the Moon tugs at our planet's seas, contributing to oceanic tidal waves, it also pulls at our atmosphere along with the Sun, creating waves in the sky.
A new study now demonstrates how some types of 'sky waves' resonate around Earth, much like how sound waves resonate inside a bell. ...
In the water, waves are produced by passing energy. Energy moving through our skies - from things like heat-produced pressure to the gravitational pull of celestial bodies - also creates waves.
These atmospheric waves don't slosh around the same way ocean waves do, but they are still recognisable if one knows what to look for: moving pockets of more tightly packed air, thousands of kilometres long.
Previous studies have focussed on localised spaces and limited time scales, allowing detection of sky waves between 1,000 to 10,000 km (600 to 6,000 miles) across, with a wave frequency of several hours. But recently available data have now opened up a much wider global view. ...
... the researchers could observe previously detected lunar and solar atmospheric waves, along with something else: "randomly excited global-scale resonant modes", first predicted in the 19th century by famous French physicist Pierre-Simon Laplace.
If the waves travel through the air at the right height and speed, they can become in tune with the atmosphere, creating resonance. This allows the waves to form a pattern stable enough to vibrate across the entire global atmosphere, like sound waves ringing through a bell. ...
