Maria Gunther: Why is the Earth spinning faster and faster?

“I am the master of time,” astronomer Daniel Gambis told DN in 2015. He was literally right. Daniel Gambis was then a leading researcher at the international organization IERS, the International Earth Rotation and Reference Systems Serviceat the Paris Observatory, and it was his responsibility to make sure to keep pace with the Earth and the clocks on the ground.

When the difference got too big – greater than 0.7 seconds – he announced to the world that it was time to introduce an extra second, the so-called leap second, at midnight last June or last December. (At present, Gambian successor Christian Besward is taking over.)

It all started already On June 3, 1955, when British physicist Louis Essen introduced the world’s first atomic clock. Since then, we have more accurate Earth clocks.

After all, the Earth is our original clock and the basis of our entire time measurement. It rotates on its axis in 24 hours, or 86,400 seconds. But the Earth is no longer accurate enough for our modern needs. So since 1972 it is the atomic clock and not the Earth that determines the official time of the world: UTC, UTC.

Since then, a total of 27 leap seconds have been introduced, so far, to prevent UTC and Earth from moving too far out of phase.

During the 1970s, 1980s, and 1990s, new leap seconds were needed every two years or every two years. But since the turn of the millennium, there have only been five. The most recent one came in December 2016, nearly 6 years ago. Since then, Earth’s speed appears to have increased instead. June 29 this year was the shortest day ever measured since we got atomic clocks.

But don’t take it now As proof that the feeling that time is passing faster and faster each year really matches what astronomers can measure. it’s not like that. exactly the contrary. The day is much longer than the day in the cradle of the earth.

As the Moon’s gravity affects the world’s oceans and causes tides, it also slows the Earth’s rotation, thus slowing its cycles. one average day About a millisecond longer each century.

But this is average. The differences from year to year can be much greater. It affects weather systems and other natural phenomena. For example, the Indian Ocean earthquake that led to the tsunami in December 2004 caused the Earth to rotate slightly faster.

No one knows for sure why the Earth’s rotation has accelerated in recent years, but there are theories. It could be because of how the mantle moves in the Earth’s interior, or that the Earth’s magnetic poles move slightly, or because of faults where the continental plates meet. It may also relate to the fact that the ice has melted on the glaciers and at the poles so that the land mass is distributed differently. Most likely it is a combination of many different influences.

The exact speed of the Earth’s rotation It has absolutely no meaning to us as biological beings. But agreeing on what time in milliseconds is can mean a lot to our technical systems, not the least of which is satellite navigation, which depends entirely on the exact time.

Leap seconds can be difficult for technology and programmers to manage, causing problems in everything from air traffic control systems to financial markets. For a long time there has been debate about whether it is time to stop using leap seconds. Should we just use the time on the atomic clock exactly as our standard time, without linking it to Earth?

If the Earth now keeps spinning faster and faster, we may need one for the first time Negation Leap second, a second of time has been removed. We have no idea how the technology will deal with that.

Maybe it’s time to give up the leap second, once and for all. On the other hand, the passage of the Sun across the sky has always been the basis for calculating our time. As Daniel Gambis says: “Technology is there to serve people, not the other way around.” Technology should adapt to us, not technology.

Read more: This summer we’re getting an extra second