Scientists from the Arizona State University suggest that these structures exist from other material than the rest of the casing. They shared their discovery in the scientific journal Nature Geoscience.
“Although we still know nothing about the origin and composition of the massive globes, we suspect that they can provide important insights into the formation of the earth,” said lead researcher Edward Garnero.
The bulbs may help explain how volcanic eruptions occur and how plate tectonics works. One colossal structure is located under the Pacific Ocean, the other is located beneath Africa and the Atlantic Ocean.
The bulbs are warmer than the remaining mantle rock and also have a different chemical composition.
There is currently very little is known about the massive bulbs.
“As a neuroscientist would find an unknown bulb in the human brain, brain scientists would perform a similar investigation,” Garnero concluded.
“We hope that other earth scientists unravel the mystery behind these bulbs in the same way.”