Earth’s magnetic field is a crucial shield that protects life on our planet from harmful cosmic radiation. However, between 590 million and 565 million years ago, this protective shield appears to have been significantly weaker, impacting the evolution of life on Earth, according to researchers.
The magnetic field of Earth is generated by the movement of molten iron in the planet’s core. Despite its strength of only 0.00005 tesla, which is much weaker than that of a magnetic resonance imaging machine, it is still strong enough for certain animals to sense and use for navigation.
The intensity of Earth’s magnetic field varies over long periods, ranging from thousands to millions of years. For example, rocks dating back 565 million years in Canada contain magnetic minerals indicating that the magnetic field at that time was only one-tenth as strong as it is today. Although Earth’s magnetic field weakens periodically during magnetic field reversals, the rocks in Canada do not reflect these short-term events, as noted by John Tarduno, a geophysicist at the University of Rochester.
Recently, the research team analyzed rocks from Brazil dating back to around 590 million years ago. They discovered that Earth’s magnetic field was even weaker during that period, measuring just one-thirtieth of its current strength. This represents the lowest magnetic field strength ever recorded for our planet, with Tarduno describing it as a near-collapse of the field.
2024-05-09 10:00:00
Source from www.sciencenews.org