One of the questions that human beings and two scientists have always asked themselves is whether Earth's rotation slows down. The answer is yes. Earth slowed down. The planet slows down and rotates more slowly. Its rotation speed determines the duration of the 24 hours of the day, and it maintains a deceleration trend that, although irregular and unpredictable, is constant and perceptible thanks to the observations and mathematical calculations of astronomers.
Therefore, we are going to dedicate this article to telling you everything you need to know about how the Earth's rotation slows down and what consequences it has for life.
Does the Earth's rotation slow down?
Although the speed of rotation is not constant and is not easy to calculate, the tendency is for it to rotate a little slower. The second extra that was added to the clock was on June 30, 2015. 2015 had 86.401 seconds, one second more than usual. A prestigious global agency, the International Earth Rotation and Reference System Service (IERS), is in charge of regularly measuring the Earth's rotation and requires six months' notice when a second should be added.
The Earth's rotation is slowing down due to the lunar tides and other factors, such as atmospheric changes (wind), which have a noticeable effect on acceleration or deceleration. When the difference between astronomical time (UT1) and atomic time (UTM) is detected, it is greater than 0,9 seconds, and leap seconds can be predicted.
The measurement of leap seconds was introduced under completely scientific standards to compensate for the influence of external factors such as the gravity of the moon, the melting of the poles or geological phenomena such as earthquakes, tsunamis or volcanic eruptions, which cause changes in the earth. Any phenomenon that can alter the distribution of the Earth's mass, from the core to the crust, affects the rate of rotation, but the effects are unpredictable.
Without this second, which has increased more than 20 times since the 1970s, the clocks that we use to measure time would not be synchronized with astronomical time, real time, and therefore would not follow the rotation of the planets and their positions with respect to the sun. The Earth has been slowing down for a long time. Millions of years ago, the days were much shorter and the time between sunrise and sunset was shortened by a few hours.
Earth's rotation slows down and its relationship with oxygen
Rising oxygen levels early in Earth's history paved the way for a spectacular diversity of animal life. But for decades, scientists have struggled to explain the factors that govern this gradual process, which It has lasted almost 2.000 million years.
Now, an international team of researchers proposes that an increase in the duration of sunlight in Earth's early days - the rotation of the young planets gradually slowing down over time, making the days longer - may have increased the amount of oxygen released by photosynthetic light with cyanobacteria, which determined the oxygenation time of the planet.
Their conclusions were inspired by a study of living microbial communities that grew in extreme conditions. at the bottom of a Lake Huron sinkhole 30 meters below the surface. The water in the central U.S. island tiankeng is high in sulfur and low in oxygen, and the brightly colored bacteria that thrive there are thought to be good analogs of the single-celled organisms that formed similar colonies to carpets thousands of years ago on the surface of the Earth and the seabed.
The researchers showed that longer days increased the amount of oxygen released by photosynthetic microbial mats. This finding, in turn, points to a previously unconsidered link between Earth's oxygenation history and its rotation rate. While the Earth now rotates on its axis every 24 hours, in Earth's infancy a day might have lasted as little as 6 hours.
Set the clock back a second or an hour?
Several of the most powerful and influential nations in the world, led by the United States, France or Germany, advocate eliminating this extra second and measuring the passage of time entirely in terms of the oscillations of barely existing carbon atoms. Cesium controls the passage of time in atomic clocks and is the most accurate.
These countries insist that all corrections can be done at once, adding an hour (3600 seconds) every 600 years, an apparent delaying tactic to avoid tackling the problem. Yes, there is some inclination to consider removing it, and doing it in larger blocks, adding one hour every 500 years, but the gap between the time marked by the sun and the civil time marked by atomic clocks will be greater and greater. GPS systems that have their own time have ignored these settings.
The disagreement with another group of countries, such as the United Kingdom or China, that supports keeping the second place has been the source of heated discussions between politics, technology and science. For staunch advocates of keeping accurate calculations of time based on the Earth's rotation, removing that extra second would be tantamount to warping a civilization's time out of sync with astronomical reality. If you consider the passage of hundreds, thousands or millions of years, that seems like a correction and a minimum change, one more second in a year, would be more than 31 million seconds. It is estimated that without an increase, one hour will be lost every 600 years.
While the rate of rotation is neither regular nor predictable, current technology and scientific knowledge allow the next leap second to be predicted two years from now. IERS is much easier with only 6 months notice. There is no predictive model. The main influence is the Moon, under which the Earth constantly deforms, slowing the Earth down by a few milliseconds.
It has been possible to clear up the doubt about whether the Earth's rotation slows down and what consequences it has.