2023-10-28 20:00:00
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Have you ever wondered why sea level rises and falls constantly? What is the reason for this phenomenon, which is now so normal in everyday life? Well, you should know that tides are one of the most surprising manifestations of the influence of cosmic objects on our planet. It is thus a natural spectacle that is repeated incessantly, driven by the action of the Moon and the Sun on our planet Earth. However, its effects and influence extend far beyond a change in the level of beaches, as it equally affects navigation, marine life and even the beliefs of certain cultures.
THE LUNAR TIDES
Thus, the Moon becomes the main cause of the tides. But why? Well, due to the action of a force called gravitational which explains the attraction between the different objects in the Universe and which was discovered by a well-known physicist: Isaac Newton. This is a law that states that all objects with a mass will feel attraction among them. In our case, this force would be responsible for keeping the Earth and the Moon together, but it would also have significant effects on the planet.
Newton, much more than a simple physicist
Precisely one of these effects are the tides because, being so close to the Earth, the Moon exerts an especially strong attraction on the planet, which also affects the planet’s own oceans and water masses. In this way, the gravitational attraction creates that, at every moment, the water column that is on the side of the Earth closest to the Moon rises above the rest slightly creating a kind of “bulge”. As a result, the water level rises in that area, producing an effect that we would know as high tide.
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However, as the Earth rotates on its axis, the area of the ocean attracted by the satellite changes, creating a regular tidal pattern along the coasts: at the point closest to the Moon the first high tide of the day will occur. The cycle repeats approximately every 24 hours and 50 minuteswhich explains why the times of high and low tide change slightly each day.
iStock
Scheme that represents how the lunar attraction produces a bulge on the planet. In the illustration, “low tide” means low tide, “high tide” means high tide, and “moon” means Moon.
SOLAR TIDES
Thus, in the same way that the Moon influences the Earth with its attraction, the Sun also has a very considerable effect on it. And, despite being further away, its mass is so big which cannot be ignored and generates an attraction on the planet that causes, as in the previous case, a bulge of the part of the oceans closest to it. However, it should be noted that the effect is much less pronounced than the moon
Even so, it is a particularly interesting phenomenon, since these two types of tides can overcome or counteract, giving rise to “special tides”. For example, when the Moon and the Sun are aligned, in a full Moon or new Moon, their effects combine, giving rise to especially high or low tides, known as spring tides. On the other hand, when the two objects are at right angles, as in the case of the waxing or waning Moon, their effects counteract each other, giving rise to less pronounced rises and falls in sea level, called neap tides.
The first spring tide of the century
TIDES AND EVERYDAY LIFE
But, beyond being a simple coastal visual spectacle, tides have a strong impact on the daily lives of people who live near the sea, significantly influencing certain activities and aspects of daily life. An example is the navigationsince the tides affect the depth of the water in ports and on the coasts, so that, at times of low tide, ships can become stranded or have certain difficulties navigating in its waters.
iStock
Boat stranded due to low tide.
It is also a point to take into account for the fishermen and all those who carry out work or recreational activities directly related to the sea. In the first case, because high or low tides can bring certain schools of fish closer or further away from the coast and, in the second, because certain sports require specific conditions for their execution: surfing will look for high tides that provide large waves, while that windsurfing will prefer low tides where access to shallow and protected areas is assured.
The tides have even significantly affected different cultures and many social movements. For example, in ancient Rome, tides were believed to be related to a magical entity known as “Living Water”, which rose and fell, creating, with its movement, the different tides. Throughout history, certain myths have also developed regarding the influence of the Moon and tides on agriculture, giving rise to the belief that planting crops in certain lunar phases can affect their growth. However, there is no solid scientific evidence to support these ideas.
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