Something from the Earth's core affects the length of days, scientists reveal changes that could impact our understanding of time.

A day on Earth lasts 24 hours, which is a widely accepted fact. However, in reality, its length can vary over decades, centuries, or even thousands of years.

The duration of a day depends on the planet's rotation speed, which can be influenced by numerous factors. Researchers from the Swiss Federal Institute of Technology Zurich have been able to more accurately determine what these factors are and how much they affect the length of a day. Their findings were published in Geophysical Research Letters.

By employing modern methods, such as neural networks, they were able to clearly identify several factors that had an impact between 720 BC and up to 2020.

Earlier studies suggested that climatic processes played a key role in changing the length of a day. However, the new research indicates that this influence is not as significant, with much greater effects coming from processes occurring in the Earth's core.

To be more specific:

• The recovery of Earth after the Ice Age accelerates the length of a day by approximately 0.8 milliseconds (ms) per century;
• The gravitational effect of the Moon, also known as tidal friction, slows down the Earth's rotation and increases the length of a day by about 2.4 ms per century.

Thus, these two processes together increase the length of a day by roughly 1.72 ms per century, representing a long-term trend.

Climate changes on the planet account for a change in the length of a day by 0.4 ms, which does not play a significant role in the researchers' model, unlike in earlier models.

On the other hand, flows of molten material in the Earth's core have been found to be capable of oscillating the length of a day by 3-4 milliseconds over millennial timescales. This effect is also noticeable on a decadal timescale, where the amplitude can reach 2-3 ms.

Therefore, due to the Moon, the length of a day will continue to increase by 1.72 ms per century in long-term scales, though this process will not be linear due to the unstable behavior of our planet's core.

As previously reported, the North Magnetic Pole of Earth continues to move, and scientists say they have never seen anything like it. It was located near the northern coast of Canada, but in the 2000s, it began heading towards Siberia.