“It's a possibility, a very strong possibility because the Earth's rotation speed is decreasing,” explains Olivier Hernandez, director of the Montreal Planetarium.
However, longer days would be a long way off. “We lose about two thousandths of a second every 200 to 400 years. So it’s not really that much. That means our days will be 25 hours in 200 to 300 million years,” Mr. Hernandez explains.
The Earth's rotation is slowed down by tides caused by the Moon. The friction caused by the tides on the Earth causes the Earth to slowly lose speed.
“This is one of the first phenomena that exists that slows down the Earth's motion,” he continues. It also has the effect of moving the Moon away from the Earth.
The Moon moves about four centimeters away from our planet each year. In a few million years, we will no longer be able to observe a total solar eclipse like the one on April 8.
“The moon will be far enough away that its diameter will not be able to completely cover the diameter of the sun,” says Mr. Hernandez. “So we have to take advantage of the solar eclipse.”
Researchers have also recently noted that the Earth's solid core is not perfectly round, but rather shaped like a rugby ball. An article published in the scientific journal nature It has shown that it has been slowing down over the past ten years.
“We have a little bit of difficulty explaining that, but we think it's basically the intersection, so the place where the solid core and the liquid core rub together, which makes the Earth's core slow down,” he notes.
Shorter cycle than before
Although we are used to 24 hours in a day, this cycle used to be much shorter. Thanks also to eclipses, it has become possible to determine that the length of days has changed over time.
“When astrophysicists analysed all the eclipses, they realised that the one dating back to 176 BC, which was supposed to pass from southern France to Paris, was found to be shifted 3,000 kilometres to the east,” says Olivier Hernandez.
This fact can be explained when we consider that the Earth was rotating faster.
A recent study conducted by scientists fromTechnical University of Munich (TUM) discovered that days were only 18 hours and 41 minutes long 1.4 billion years ago. In the age of dinosaurs, a day lasted 23 hours.
