The Resonant Pause: How Tidal Forces Cancelled Out, Slowing Earth’s Rotation

An atmospheric effect that occurred billions of years ago caused various tidal forces to cancel out, resulting in Earth’s rotation slowing down and the lengthening of its days being put on pause. According to a recent study published in Science Advances, astrophysicists have discovered that from 2 billion to 600 million years ago, Earth’s days were approximately 19.5 hours long due to the cancellation of tidal forces. If this cancellation had not occurred, our present days might be over 65 hours long.

The research team emphasized that the fact that our day is currently 24 hours long is not a coincidence. The length of Earth’s days has gradually increased over time as lunar tidal forces have slowed down its rotation. Tidal forces from the Moon, generated by its gravitational pull, cause bulges on the side of the Earth closest to the Moon and the side furthest from it, resulting in high tides in the oceans. These bulges resist the spin of the Earth, creating friction that slows down its rotation.

There are two types of solar tides that also affect Earth’s rotation. The first type, called solar tidal torque, operates similarly to the Moon’s tidal forces and causes small changes in ocean tides, further slowing down Earth’s spin. The second type, known as thermal tidal torque, occurs when sunlight heats the atmosphere, causing it to expand. This expansion creates another handle for the Sun’s gravity to interact with, pushing Earth to rotate faster. However, the Moon’s gravity generates twice the force of the Sun’s gravity due to its proximity to Earth.

Around two billion years ago, Earth’s atmosphere was warmer, which affected the thermal waves created by sunlight. Higher temperatures led to higher wave velocities, and the frequency at which these waves traveled through the atmosphere created an atmospheric resonance. This resonance and the length of the day remained in sync for approximately a billion years, with atmospheric waves resonating every time Earth completed about half a rotation.

The resonance period was almost exactly double the rotational period of Earth, resulting in stronger atmospheric tides caused by the Sun. This torque roughly countered the lunar tides, causing Earth to move neither slower nor faster. It wasn’t until 600 million years ago, a billion years after the resonance started, that days began to grow longer again.

The study’s findings were confirmed by examining geological evidence of high and low tides from ancient rock formations. The researchers concluded that the long duration and relatively recent occurrence of this resonant state may be responsible for the current 24-hour day.

However, the article raises concerns about the potential impact of rising temperatures due to global warming. As resonance and rotation become more out of sync, solar tidal forces are less able to counter the lunar tidal forces that have gradually extended Earth’s days over time. While having a few extra hours in the day may seem appealing, it should not come at the expense of our planet.

In conclusion, the cancellation of various tidal forces billions of years ago caused Earth’s rotation to slow down and put the lengthening of its days on pause. This phenomenon, along with the resonance between atmospheric waves and the length of the day, has contributed to our current 24-hour day. However, the effects of global warming may disrupt this delicate balance and potentially lead to even longer days in the future.

How did an atmospheric effect approximately 2 billion years ago lead to the cancellation of tidal forces and a slowdown in Earth’s rotation?

Go, an atmospheric effect took place that resulted in the cancellation of tidal forces and caused Earth’s rotation to slow down. This event, as revealed by a recent study published in Science Advances, led to Earth’s days being approximately 19.5 hours long from 2 billion to 600 million years ago. Without this cancellation, our present days might have been over 65 hours long.

The research team emphasized that the current 24-hour length of our day is not a coincidence. Over time, the length of Earth’s days has gradually increased due to the slowing down of its rotation by lunar tidal forces. Tidal forces from the Moon, created by its gravitational pull, create bulges on the sides of the Earth closest and furthest from the Moon, resulting in high tides in the oceans. These bulges resist Earth’s spin, creating friction and gradually slowing down its rotation.

Aside from lunar tidal forces, solar tides also impact Earth’s rotation. The first type, called solar tidal torque, operates in a similar manner to the Moon’s tidal forces and brings about small changes in ocean tides, further decelerating Earth’s spin. The second type, known as thermal tidal torque, occurs when the atmosphere expands due to sunlight heating it. This expansion provides another point of interaction for the Sun’s gravity, pushing Earth to rotate faster. However, the Moon’s gravity exerts twice the force of the Sun’s gravity due to its proximity to Earth.

Approximately two billion years ago, an atmospheric effect took place that caused tidal forces to cancel out, slowing down Earth’s rotation. This resulted in days that were around 19.5 hours long. A recent study published in Science Advances revealed this information, emphasizing that our current 24-hour days are not a coincidence. Over time, Earth’s rotation has gradually slowed down due to lunar tidal forces. The Moon’s gravitational pull creates bulges on the sides of the Earth, producing high tides and resisting its spin. This friction slows down the rotation. Solar tides, both from the Sun’s gravitational pull and the expansion of the atmosphere through sunlight, also impact Earth’s rotation. However, the Moon’s gravity is twice as strong as the Sun’s, leading to its dominant influence.