Even though the day remains constant for us, from a planetary perspective its duration is slowly increasing. The Moon drifts away from Earth annually, which affects our planet’s rotation and, ultimately, the length of the day. Ecoticias reports this.
Why our day is gradually becoming longer
Every day for us is 24 hours, but from a geological viewpoint, this cycle is slowly shifting. The Moon moves away from Earth by about 3.8 centimeters yearly, causing a gradual slowing of our planet’s spin.
This process, happening millimeter by millimeter, alters the duration of the day, and also impacts the tides, which in turn affect ecosystems.
“Measurements indicate that each day gets longer by 1-2 milliseconds per century, which is unnoticeable within the span of a human lifetime,” scientists state.
How scientists learned about faster Earth rotation in the past
To grasp how Earth spun in earlier times, scientists employed an unusual method—examining fossilized clam shells that lived 70 million years ago, during the dinosaur epoch.
These mollusks, much like trees, left microscopic records of their growth, from which both daily and seasonal cycles could be counted.
By studying these layers, researchers found that at the end of the age of dinosaurs, a year comprised roughly 372 days, not 365 as now. This confirms that during that period, Earth rotated faster, and days were shorter—about 23.5 hours long.
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Causes and consequences of tidal friction
So, why is the Moon receding from Earth, and why is the day length gradually extending? It’s all due to tidal friction, which arises from the Moon’s gravitational pull on Earth’s oceans.
When our planet rotates quicker than the Moon moves along its orbit, the tidal bulges get ahead of the line connecting Earth and the Moon. This displacement causes additional attraction toward the Moon, which in turn slightly decelerates Earth’s rotation. Every year the Moon moves farther away, and Earth’s spin becomes slower.
“Each year the Moon moves away from Earth by about 3.8 centimeters, impacting the duration of the day,” scientists explain.
How changes in day length affected ecosystems
For coastal ecosystems, the ebb and flow of the tides play a vital role. They dictate how often salt marshes drain, how long flats are exposed for shorebirds, and how nutrients reach the sea.
In the past, when days were shorter and tides more vigorous, conditions for marine life were different. This is supported by geological evidence from ancient tidal deposits, which show that conditions were far more dynamic then.
“Previously, intense tides likely resulted in different patterns of coastal erosion and alterations in the lives of marine organisms,” researchers note.
How the Moon and Earth influence climate and life
As the Moon gradually drifts from Earth, its influence on the planet’s climate and ecosystems is changing. In the distant future, if this trend continues, one side of Earth might always face the Moon—a phenomenon known as tidal locking.
However, these shifts occur so slowly that they might only impact the planet after billions of years, whereas the Sun, gradually growing brighter, could evaporate the oceans within a billion years, hindering further tides.
“The tidal forces that stabilize the Earth’s axial tilt are crucial in maintaining climate stability, which is necessary for the existence of complex life,” scientists assert.
Ecological lessons and the future
This process of lunar recession and Earth’s rotational slowdown reminds us how important it is to comprehend long-term planetary changes. Although today’s alterations are gradual, they can offer valuable insights for scientists studying Earth’s history and its future.
Meanwhile, the most critical factors for climate and environmental shifts remain in our hands—namely, our energy policies, greenhouse gas emissions, and other choices we make today.
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