The data suggest that the ancient magnetic field strength was at least 50 percent of the present-day field, which typically measures 40 to 60 microteslas, says Tarduno. This means that a magnetosphere was definitely present, sheltering the Earth 3.2 billion years ago.
To further ensure his readings were accurate, Tarduno also checked the alignment of the magnetism in the particles, which record the polarity of the Earths field at that time and location. By comparing the polarity to that of other samples of similar age and location, Tarduno could ensure that his measurements were not likely from later geological heating, but truly from 3.2 billion years ago.
Tarduno is now pushing back in time to 3.5 billion-year-old rocks to further investigate when the Earths inner core first formed, giving new insights into early Earth processes that also may have had an effect on the atmosphere and the development of life on the planet.