June 29 was the shortest day in Earth’s history

THE June 29th will go down in history as the Earth’s shortest day. Due to a wobble on its axis, the day lasted less than 24 hours, or 1.59 milliseconds less than the 86,400 seconds that make up the day.

In recent decades the Earth slowed her rotationoffering marginally longer days, but in recent years this trend has reversed and the days are getting shorter and shorter.

In fact, if the Earth continues to accelerate, it may be necessary for the first time to remove a second from atomic clocks.

But what is the reason for these fluctuations?

The Earth is not a perfect sphere. It has a bulge at the equator, while the poles are more flattened, making its shape slightly elliptical. The Moon’s gravity and even ocean tides can affect its rotation.

This oscillation was detected in the late 1880s by the astronomer Seth Carlo Chandler and named Chandler swingwhile it started to slow down in the early 2000s, reaching a minimum in 2017. Between 2017 and 2020, it disappeared.

Although it doesn’t affect us in our daily lives, these oscillations are important to track so that atomic clocks maintain their accuracy so that satellites in space and GPS systems can be accurately synchronized.

View the news feed and get the latest news.