Scientists from the School of Environmental Sciences at the University of Liverpool in England led a group of scientists from around the world to analyze magnetic records from prehistoric igneous rocks. The team found a significant difference in the strength level of the planet's magnetic field between one billion and one and half billion years ago. The theory includes a higher magnetic field specifies the initial appearance of a solid iron at the planet's core. Scientists believe this is also the point when the inner core started to solidify and freeze.

Approximately 4.5 billion years ago, prior to the formation of a solid inner core, the planet was believed to be a huge blob of liquefied rock. In the course of time, this molten mess grew a 'crust' as the surface began to cool down. The Earth's solid core is relatively new at one billion years old. Lead author Dr. Andy Biggin, who is an expert in palaeomagnetism, commended that this could alter the way we understand our planet's history and its layers.

"The results suggest that the Earth's core is cooling down less quickly than previously thought which has implications for the whole of Earth Sciences," said Biggin in a press release. The findings suggest the Earth's core grows at 0.04 inches (one millimeter) in diameter annually. The Earth's inner core is made roughly the size of Pluto.

The research team claims that the Earth's magnetic field, which protects it from dangerous solar radiation, is the reason why the planet is teeming with life. Further understanding of the planet's core along with the magnetic field will help the scientific community foresee the fate of its electromagnetic future. So far, the key findings indicate that the planet's magnetic field, which is powered by its strong core, will keep its strength for a long time, roughly another billion years. The data is in direct opposite with Mar's magnetic field which started strong in its early years. The Red Planet's magnetic field disappeared around four billion years ago.

The research was published in the journal Nature on Oct. 7, 2015.