Scientists analyzing new data have concluded that our Earth is much younger than previously estimated. After studying the magnetic signature of ancient igneous rocks, an international group of scientists realized that there was a sharp increase in the strength of the Earth's magnetic field between one billion and 1.5 billion years ago. This increased strength has been correlated to the time when solid iron first occurred in the Earth's center, or the point in the history of the creation of the Earth when iron first started "freezing" from an erstwhile all-molten core, reports the Christian Science Monitor.
"This finding could change our understanding of the Earth's interior and its history," said lead author Andy Biggin in a press release. Biggin works at the University of Liverpool's School of Environmental Sciences.
"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. It also suggests an average growth rate of the solid inner core of approximately 1 millimeter per year which affects our understanding of the Earth's magnetic field," Biggin said, according to ABC News.
The question of when molten iron started to freeze forming the inner core has been debated hotly for years. "Studying the magnetism of ancient rocks is a huge scientific challenge, because old rocks can lose their magnetic memory, or the magnetic signals they carry can become overwritten and corrupted (just like the files on your hard drive). However, it is one of the best ways to look for concrete evidence of when the core started to solidify, said Richard Harrison of the University of Cambridge, according to BBC. Harrison was not a part of the study that has been published in the Nature journal.
The study, a collaboration between scientists at the Universities of Liverpool, Helsinki, Michigan Tech, UC San Diego and the Chinese Academy of Sciences has also concluded that the Earth's magnetic field will be active for approximately a billion more years, in sharp contrast to Mars "which had a strong magnetic field early in its history, which then appears to have died after half a billion years."