2023-07-05 14:50:11
Gravity is not the same everywhere on Earth. These differences are not noticeable naturally, but actually exist. However, there is a point on our planet where gravity is particularly weak and this is in the Indian Ocean. As part of their study, scientists may have discovered why.
The Indian Ocean geoid anomaly
The Earth is not a perfect sphere and therefore matter and mass are not evenly distributed. However, it is precisely this same mass that determines gravity. Thus, gravity (or force of attraction) is not the same everywhere. Our planet also has bumps (mountains) and holes (seas and oceans), so there must be other variations. theoretically difficult to detect.
One of these little-known areas was the main subject of a study published in May 2023 in the journal Geophysical Research Letters. In recent years, satellites have measured variations in the force of attraction of our planet and have detected an area where gravity is at its weakest. This area, which covers a area of three million km², is found in the Indian Ocean, regarding 1,200 km southwest of India. However, the level of the ocean there is somehow 105 m lower than normal. This area also has a name: the Indian Ocean geoid anomaly.
Credits: Bangalore Institute of Sciences / Geophysical Research Letters
A plausible explanation
According to the study conducted through nineteen computer simulations movements inside the Earth’s mantle by researchers from the Institute of Sciences in Bangalore (India), there may be an explanation. Each of these simulations concerns different parameters linked to the fluxes of magma within the mantle relating to changes that have occurred there. over the past 140 million years.
However, six of these scenarios correspond to the geoid anomaly of the Indian Ocean. It is regarding lower density magma flow and disturbances due to partial subsidence of the ancient Tethys tectonic plate. This tectonic plate is what remains of the ancient ocean of the same name. Recall that 120 million years ago, Africa and India separated, the latter having moved towards the Tethys Ocean, thus creating the current Indian Ocean.
If this research is very interesting, it is important to underline that at present, no technology makes it possible to observe the flows of magma in the mantle. Indeed, this layer of the Earth begins at a depth of 35 km under the continents and its thickness reaches the core. Thus, it is quite possible that other secrets remain to be discovered on the distribution of gravity on our planet.
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