Today, ocean tides are one of the most reliable phenomena in the world. They are periodic rises and falls in the level of the sea. They are also formed by the gravitational pull of the Moon together with the Sun on the water in the ocean. Even though the Moon is much smaller than the Sun, it has a higher gravitational attraction for the Earth since the Moon is very close to the Earth. This results in oceans bulging out in the direction of the moon. Read on to explore more facts about ocean tides.
Spring tides are particularly strong tides (they don’t have anything to do with the spring season). They usually occur when the Moon, the Sun, and the Earth are in a line. The gravitational forces of the Sun and the Moon both contribute to the tides. Spring tides occurs during the new moon and the full moon.
The key to appreciating how the ocean tides occur is understanding the relationship between the Sun and Moon and the motion of our planet. As the Earth rotates on its own axis, the ocean water is kept at equivalent levels around the planet by the gravity of Earth pulling inward and the centrifugal force pushing outward.
But, the gravitational forces of Moon are sufficiently strong to disturb this balance by accelerating the flow of water towards the Moon. This causes the water to ‘bulge.’ Also, as the Moon orbits our planet as it rotates, the bulge also moves. The regions of the Earth where the bulging happens experience high tide and the other places are subject to a low tide.
There are several factors involved in predicting the ocean tides. Apart from the motion of the Sun and Moon, timing of the ocean tides are also influenced by the declination of the Moon (angular height above the equator), the topography of the ocean floor, the local geography of the coastline, and the depth of the water, among other factors. Hence, the tides cannot be perfectly predicted mainly by astronomical calculations which track the Moon and Sun. For highest accuracy, tide prediction tables always integrate the data from real observation, usually over a period of several years.
Interesting Facts About Ocean Tides:
- Ocean’s tides are usually created by combining the gravitational attraction of the Sun and the Moon, combined with Earth rotation.
- The tides are long-period waves which appear as a result of rising and fall of the sea since they reach the coastline.
- The earth rotates on its axis once in every 25 hours, and the moon revolves around the earth once in each 27 days.
- Many places in the ocean experience two low tides and two high tides every day.
- The tidal troughs are always separated by almost 12 hours.
- The alignment of the Sun, Moon and Earth cause the more gravitation pull which results in maximum tides.
- The lowest tide height difference usually occurs in the deepest part of the ocean at about 1.6ft.
- The highest tide height difference to ever happen is in the Bay of Fundy in Nova Scotia, Canada at about 15 meters!
- There are times in the rotation of the moon which is at right angles to the earth-sun line. This is in the last quarter and first quarter phase. This causes interference between the moon’s and the sun’s gravitational pull and results in weaker tidal troughs. These are known as Neap Tides.
- There are times during the rotation of the moon that is on the same side of the earth as the sun. This happens at the full moon and new moon phase. It results in greater tidal troughs. These are known as Spring tides.