The team believe that a previously unexplained isotopic ratio from deep within the Earth may be a signal from material from the time before the Earth collided with another planet-sized body, leading to the creation of the Moon. This may represent the echoes of the ancient Earth, which existed prior to the proposed collision 4.5 billion years ago. This work is being presented at the Goldschmidt conference in Sacramento, California.
The currently favored theory says that the Moon was formed 4.5 billion years ago, when the Earth collided with a Mars-sized mass, which has been given the name "Theia". According to this theory, the heat generated by the collision would have caused the whole planet to melt, before some of the debris cooled and spun off to create the Moon.
According to lead researcher Associate Professor Sujoy Mukhopadhyay (Harvard): "The energy released by the impact between the Earth and Theia would have been huge, certainly enough to melt the whole planet. But we believe that the impact energy was not evenly distributed throughout the ancient Earth. This means that a major part of the impacted hemisphere would probably have been completely vaporized, but the opposite hemisphere would have been partly shielded, and would not have undergone complete melting".
But not only an ancient world exists inside the earth. Researchers from Northwestern University and the University of New Mexico provided the first ever evidence for potentially oceans worth of water deep beneath the United States.
Northwestern University geophysicist Steve Jacobsen and University of New Mexico seismologist Brandon Schmandt have found deep pockets of magma located about 400 miles beneath North America, a likely signature of the presence of a massive reservoir of water three times the size of Earth's oceans. Though not in the familiar liquid form — the ingredients for water are bound up in rock deep in the Earth's mantle — the discovery may represent the planet's largest water reservoir.
Schmandt and Jacobsen's findings build on a discovery in which scientists found a piece of the mineral ringwoodite inside a diamond brought up from a depth of 400 miles by a volcano in Brazil. That tiny piece of ringwoodite — the only sample in existence from within the Earth — contained a surprising amount of water bound in solid form in the mineral.
Fragments of the blue colored mineral ringwoodlite synthesized in the laboratory. (Credit: Steve Jacobsen - Northwestern University).
"The ringwoodite is like a sponge, soaking up water," Jacobsen said. "There is something very special about the crystal structure of ringwoodite that allows it to attract hydrogen and trap water.
The presence of liquid water on the surface is what makes our "blue planet" habitable, and scientists have long been trying to figure out just how much water may be cycling between Earth's surface and interior reservoirs through plate tectonics. The new findings will also help scientists better understand Earth's water cycle.
According to the Hollow Earth Hypothesis, planet Earth is either wholly hollow or otherwise contains a substantial interior space.via