Earth also wanted 2020 to end faster. Our planet has turned particularly quickly on itself during the last twelve months. She thus beat in 2020 no less than 28 times her shortest day record. With a peak on July 19, where it made its rotation a millisecond and a half less than the 86,400 seconds it takes on average for that. The previous record dated back to 2005.
Explaining this phenomenon is not easy. The speed of the Earth’s rotation varies with the winds and tides. But since the 1970s, there has been a fundamental trend. It spins faster, with no real explanation.
“We observe what we call decadal variations whose cause escapes us. They say that it results from processes inside the Earth “, explains Christian Bizouard, astronomer at the observatory of Paris, joined by RTL.
The duration of the Earth’s rotation is used to fix the universal time of atomic clocks that were used in the past to calculate positioning, especially at sea. But today, GPS systems no longer need it.
“Apart from a few amateurs who still use universal time for positioning at sea, with obsolete precision of the order of a kilometer, it is no longer useful today. We need much higher precision, of the order of 10 microseconds. We directly use the time of rotation of the Earth determined by the satellites “, underlines Christian Bizouard.
And if the Earth continues to accelerate, it may be necessary to reset the atomic clocks by moving them forward a second.