In the Indian Ocean region, gravity is much lower than normal. The research duo now want to solve the mystery.
BANGALORE – Even if it seems surprising: Gravity does not work everywhere on Earth, because the Earth is not an ordinary ball, but more like a potato. There are areas where gravity is a little stronger or weaker, in part due to the fact that the mass inside the Earth is not evenly distributed. Places with particularly low gravity are called “gravity holes”. Earth’s lowest gravity operates in a very remote area of the Indian Ocean, known as the Indian Ocean Low Geode (IOGL).
The sea floor at IOGL is 106 meters lower than average — because gravity is lower there but higher in the area, according to geophysicist Atreyi Ghosh of the Indian Institute of Science (IISc) in Bangalore. Low gravity in the Indian Ocean region has long been a mystery to researchers, but now Ghosh and his colleague Dipanjan Pal hope to solve the mystery.
‘Gravity hole’ in the Indian Ocean: Possibly caused by hot magma flows
The two researchers at the International Institute of Ismaili Studies (IISc) have a study in the journal Geophysical Research Letters published, where they reconstructed 140 million years of tectonic plate movement. The researchers found that an ancient ocean plate that was sinking into the Earth’s mantle below the African continent is causing hot, low-intensity magma flows. The material was collected in the area of the Indian Ocean where the gravitational hole is now located. “What we’re seeing is hot, low-density material sitting under the Indian Ocean that’s lowering this geoid,” Ghosh explains. Compared with the Scientific American.
An accurate knowledge of the geoid—the distribution of gravity on Earth—isn’t just important to science. Knowledge is also necessary to be able to determine the correct height using GPS. Science uses accurate data from geodes to be able to accurately measure, for example, ocean circulation or changes in sea level.
Low gravity in the Indian Ocean: the area stays for a long time
According to the researchers, the gravitational hole in the Indian Ocean has existed in its current form for about 20 million years – and will likely remain so for the next several million years. “Only when the temperature anomalies that are causing this lower geode to shift from where it is today will the lower geode begin to melt,” Pal says with certainty. (unpaid bill)
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