The inner core is the deepest layer on Earth. It is a huge ball of solid iron (slightly larger than Pluto) surrounded by an outer core in a liquid state. The scientific community had made many estimates about when this inner core formed (with a range between 500 and 2 billion years). Now, research carried out by scientists at the University of Liverpool (UK) has determined that the nucleus formed between 1,000-1,500 million years ago, which means that the Earth lived about 3,000 years without this solid sphere .
The Earth’s core, formed mainly by an alloy of iron and nickel, is located more than 3,000 kilometers away towards the interior of our planet and knowing when it originated is key to understanding our entire history, that of the planet on which we live and of all the beings that inhabit it.
However, accessing such depths is a very complex task. To overcome this obstacle, the researchers analyzed the magnetic records of igneous rocks that were formed after the cooling of molten magma rocks , discovering an exaggerated increase in the strength of the Earth’s magnetic field at a certain moment in the life of our planet. Thus, examination has revealed that the nucleus is between 1,000 and 1,500 million years old.
And it is that this remarkable magnetic change marks the moment in which the solid sphere was formed after the cooling of the great liquid iron ball inside the Earth. Furthermore, the calculations presented in the study seem to indicate that the core is cooling much more slowly than expected: “The results suggest that the Earth’s core is cooling more slowly than previously thought , which has implications for the whole of Earth Sciences. It also suggests an average growth rate of the solid inner core of about 1 millimeter per year , which affects our understanding of the Earth’s magnetic field, ”explains Andy Biggin, leader of the research.
The study has been published in the journal Nature .
