A new research performed by scientists from the University of Liverpool’s School of Environmental Sciences determined that the Earth’s inner core was formed 1 to 1.5 billion years ago. The study was published in the journal Nature.
According to previous seismological studies, the Earth’s inner core is mostly a solid ball with a radius of about 1220 kilometers (about 70 percent of the Moon’s radius.) Scientists are convinced that it mainly consists of an iron-nickel alloy and it is approximately at the same temperature as the surface of the Sun.
“The theoretical model which best fits our data indicates that the core is losing heat more slowly than at any point in the last 4.5 billion years and that this flow of energy should keep the Earth’s magnetic field going for another billion years or more,” said study co-author Andy Biggin in a press release, as NatureWorld reported.
Biggin, who is also a paleomagnetism researcher, which is the study of the record of the Earth’s magnetic field in rocks – sediment or archaeological materials – explained the situation around the magnetic fields and said that this new finding could change the understanding of the Earth’s interior and its history.
The study behind the magnetic records from ancient igneous rocks revealed that there was a sharp increase in the intensity of the Earth’s magnetic field between 1 and 1.5 billion years ago. Also, scientists found that the Earth’s magnetic field, which is powered by the swirling flow of liquid iron surrounding the inner core, could continue going strong for a long period. In addition, the Earth is estimated to be 4.5 billion years old.
“The timing of the first appearance of solid iron or ‘nucleation’ of the inner core is highly controversial but is crucial for determining the properties and history of the Earth’s interior and has strong implications as to how the Earth’s magnetic field – which acts as a shield against harmful radiation from the sun, as well as a useful navigational aid – is generated.” Biggin explained, as Eurekalert reported.
A magnetic field increase is associated with the first occurrence of solid iron at Earth’s centre and the point in Earth’s history at which the solid inner core first began to freeze out from the cooling molten outer core, according to Eurekalert.