Why Is The Earth's Rotation Speeding Up? Here's the Reason Why

Earth's rotation is subtly accelerating, and scientists are intently tracking the trend. Usually, our planet takes 24 hours, or 86,400 seconds, to finish one complete spin. 

However, on July 9, 2025, Earth completed its rotation approximately 1.3 milliseconds faster than usual. That's quicker than the blink of an eye, but it matters for structures like GPS and atomic clocks that depend upon ultra-precise timing.

So, what is causing this change? Imagine a discerning skater spinning: after they pull their palms in, they spin faster. Earth works the same way. 

When mass shifts closer to the centre—like melting glaciers shifting water toward the equator or the Moon pulling from the poles as opposed to the equator—Earth spins a piece faster. 

Other elements, including earthquakes, ocean currents, and seasonal changes in tree growth, can also affect rotation speed. While we may not notice the distinction, scientists adjust these shifts to ensure the accuracy of global time standards. 

Why Is The Earth's Rotation Speeding Up?

The Earth's rotation is accelerating due to several factors. Here are some possible reasons:

• Moon's Position: The moon's orbit around Earth plays a significant role. When the moon is at its maximum distance from Earth's equator, it can cause the planet to spin faster. This is predicted to happen on July 9, July 22, and August 5, resulting in shorter days by 1.30, 1.38, and 1.51 milliseconds, respectively.
• Earth's Molten Core: Changes in the movement of Earth's molten core can affect the planet's spin speed. The core's complex motion is one of the factors scientists believe could be contributing to the acceleration.
• Earthquakes and Mass Shifts: Significant earthquakes, like the 2011 Japan earthquake, can rearrange the Earth's mass, causing it to spin slightly faster or slower. This effect is small but measurable.
• Ocean Currents and Atmospheric Changes: Powerful ocean currents and changes in atmospheric pressure can also contribute to the Earth's variable spin speed. Seasonal shifts, like the growth of leaves on trees during summer, can slow the spin slightly.
• Climate Change: The melting of glaciers and polar ice can shift mass on the planet, potentially affecting the Earth's rotation. However, this typically slows the Earth down, rather than speeding it up.

The Earth's rotation has been speeding up since 2020, with the shortest day recorded on July 5, 2024, when the Earth spun 1.66 milliseconds faster than it usually does.

Factors Contributing to Earth's Increased Rotation Speed

Several factors are thought to contribute to the Earth's increased rotation speed:

• Redistribution of Mass: Changes in the distribution of mass around the Earth, such as the melting of glaciers or shifts in ocean currents, can affect the planet's rotation speed.
• Earth's Core: The movement of molten iron in the Earth's core can influence the planet's magnetic field and rotation speed.
• Atmospheric and Oceanic Changes: Changes in atmospheric pressure, ocean currents, and the global movement of water can contribute to variations in the Earth's rotation speed.
• Seismic Activity: Significant earthquakes can cause slight changes in the Earth's rotation speed by redistributing mass within the planet.
• Climate Change: Large-scale changes in the planet's climate, such as the melting of ice caps and glaciers, can impact the Earth's rotation speed.
• Moon's Gravitational Pull: The moon's gravitational interaction with the Earth can cause slight variations in the planet's rotation speed.
• Changes in the Earth's Magnetic Field: Shifts in the Earth's magnetic field can also influence the planet's rotation speed.
• Planetary Alignment: Some research suggests that the alignment of the Earth, Moon, and Sun can cause slight variations in the Earth's rotational speed.

These factors can interact with each other in complex ways, making it challenging to pinpoint a single cause for the Earth's increased rotation speed.

The Impact of Lunar Gravity and Tidal Forces

The moon's gravity has a profound effect on Earth, mainly in the form of tidal forces. Here are a few outcomes:

• Tidal Acceleration: The moon's gravity causes the oceans to puff up, creating tides. This interplay additionally slows down the Earth's rotation and will increase the length of a day by approximately 1.78 milliseconds per century.
• Stabilisation of Earth's Axis: The moon's gravitational pull allows the Earth's axis, which is tilted at about 23.5 degrees. This tilt is chargeable for the conversion seasons.
• Earth's Rotation and Orbit: The moon's gravity has been slowing down the Earth's rotation since its formation. In the remote past, a day on Earth was much shorter, lasting around 6 to 8 hours.
• Effects on Earth's Crust: Some studies indicate that the moon's tidal forces can trigger earthquakes and volcanic activity by placing extra strain on the Earth's crust.
• Impact on Marine Life: Tidal forces influence the distribution and behaviour of marine life, specifically in coastal ecosystems. Many species depend on the tidal cycles for feeding, breeding, and migration.
• Stabilisation of Earth's Climate: The moon's gravitational impact can also play a role in stabilising the Earth's climate by affecting ocean currents and the global distribution of heat.

The moon's gravitational pull has a substantial effect on the Earth's oceans, rotation, and weather, making it an important component of the Earth-moon machine.