You might think of Earth as a perfectly shaped sphere, especially when you look at the planet’s profile from beyond its atmosphere. Every picture we’ve seen of the planet makes it look like a perfect circle. However, that isn’t quite the case. In fact, there are areas that are much flatter than others, and if new research is to be believed, there’s even a “gravity hole” in the middle of the Indian Ocean.
Of course, this “hole” isn’t what you might think of when you hear the term. Water isn’t draining from the ocean, and it isn’t a mysterious blue hole. Instead, the “hole” is simply a spot in the Earth’s geoid where gravity is lower than average, thus making the sea level there lower than the global average. But what exactly is causing this “gravity hole?” Researchers may have finally found an answer.
According to a new study published in Geophysical Research Letters, this lower pull of gravity is most likely caused by magma plumes. The plumes most likely helped the Earth take its current shape over 20 million years ago, when the current geoid (an imaginary visualization of how Earth’s Sea level looks) was formed.
The plumes are most likely continued to flow for the past 20 million years, and when they stop, it’s likely that the low geoid shift we see in the middle of the Indian Ocean will shift out, causing the gravity hole to dissipate. It’s an intriguing revelation that could help us understand the planet’s geoid quite a bit better, especially as researchers look deeper into it.
While it’s impossible to see the difference atop the surface of the ocean, it is there, and the researchers say that it is unlikely that the plumes responsible for the gravity hole will cease for another several million years. Until then, we’ll hopefully be able to learn more about our geoid and the exact causes of the different gravitational pulls across our planet.