NASA Says the Earth’s Rotation is Slowing, Could Cause Major Earthquakes
Earth’s rotation is slowing down as the Moon moves farther away from the planet – and scientists believe it could cause major earthquakes.
Earth’s rotation is slowing as our planet uses energy to keep the tidal bulge ahead of the Moon’s orbit. The Moon’s gravity keeps Earth’s rotation in check, and to do this the lunar satellite’s orbit must be slightly ahead of Earth’s. As the Moon attempts to regulate Earth’s rotation and slow it down, the Moon moves slowly away.
According to Matthew Funke, solar system ambassador for NASA’s Jet Propulsion Laboratory, who wrote on Q+A website Quora: “The Moon’s gravity creates a tidal bulge on the Earth. This bulge attempts to rotate at the same speed as the rest of the planet.
“As it moves ‘ahead’ of the Moon, the Moon attempts to pull it back. This slows the Earth’s rotation down.
“One of the rules of the Universe is that ‘angular momentum’ can’t go anywhere — even if individual pieces speed up, slow down, or change direction, the sum total of angular momentum cannot change.
“The Earth loses angular momentum when the Moon slows it down, so the Moon has to gain it — and it does, by moving further away in its orbit.
“The Moon is currently receding from the Earth by about one and a half inches per year.”
This could lead to major earthquakes down the line.
A slower rotating globe leads to stronger and more frequent earthquakes – exactly why this is the case is unclear, but experts believe it could be down to changes in the Earth’s core which ultimately has an effect on the surface.
Research from Roger Bilham of the University of Colorado in Boulder and Rebecca Bendick of the University of Montana in Missoula looked at earthquakes with a magnitude higher than seven since 1900.
The duo found five years since the turn of the 20th century where there were significantly more magnitude 7.0-plus earthquakes – all of which were years that earth’s rotation speed had slowed down slightly.
Prof Bilham said: “In these periods, there were between 25 to 30 intense earthquakes a year.
“The rest of the time the average figure was around 15 major earthquakes a year.
“The correlation between Earth’s rotation and earthquake activity is strong and suggests there is going to be an increase in numbers of intense earthquakes.”
However, this is not expected to happen for billions of years, according to Physicist Paul Walorski who explained on physics forum PhysLink: “The slowing rotation of the Earth results in a longer day as well as a longer month.
“That’s been projected to happen once the day and month both equal about 47 (current) days, billions of years in the future.”