Life on our planet, as we know it, could not exist without the Earth’s geomagnetic field. Without it, our planet would be exposed to the sun’s dangerous radiation streams, also called solar winds. There was a time when this field became so weak that it almost disappeared, which could have led to Earth being an uninhabited planet. Luckily, he recovered. As? The keys to this ‘mystery’ have been collected in a study conducted by a team of scientists from the University of Rochester, recently published in the journal Nature Communications.
To understand it better, let’s go back a little to our school days, when we learned that the Earth is made up of layers (crust, mantle, liquid outer core and solid inner core). In the liquid outer core, the molten iron causes electrical currents and drives a phenomenon called a geodynamo, giving rise to the magnetic field. Researchers suggest that, about 565 million years ago, the strength of the geomagnetic field decreased to 10% of its current strength. Fifteen million years later, however, this field began to renew rapidly and recovered in a few tens of millions of years (a short time span on geological time scales).
Researchers believe that this early recovery was due to the fact that, right at that same moment, the solid inner core of the Earth began to form. «To generate and maintain a magnetic field, convection (heat transfer) must occur in the liquid core of the planet. This convection can be a consequence of the heat that is released from the outer core to the mantle, or of the energy released by the solid inner core. If neither of these two options is available, the magnetic field collapses,” explains John Tarduno, Professor of Geophysics in the Department of Earth and Environmental Sciences and research dean of Arts, Sciences and Engineering at Rochester.
The magnetic field protects the Earth from solar winds.
If these radiation currents that
If the Sun releases space reaching our planet, many species could disappear.
Cortex
Where is
life
Outer core
liquid
Where the magnetic field is created.
The molten iron of the outer core generates electrical currents, giving rise to a phenomenon called
geodynamo that produces the magnetic field.
Source: University of Rochester.
The magnetic field
protects the Earth from solar winds.
If these currents of radiation that the Sun releases into space
reach our planet, many species could disappear.
Cortex
where is life
Core
solid interior
Composed of iron
and nickel.
Outer core
liquid
Where the magnetic field is created.
The cast iron of the outer core generates
electrical currents giving rise to a phenomenon called geodynamo that produces
the magnetic field.
Source: University of Rochester.
If these currents of radiation that the Sun releases
to space will reach our planet, many
species could disappear.
The magnetic field
protects the Earth from solar winds.
Cortex
Where is
life
Core
solid interior
Composed of iron and nickel.
Outer core
liquid
Where is it created
the magnetic field.
The cast iron of the outer core generates
electrical currents giving rise to a
phenomenon called
geodynamo that produces
the magnetic field.
Source: University of Rochester.
In the case of Earth, the creation of the solid inner core was decisive in restoring the magnetic field. «The solid inner core is tremendously important. As soon as the field grew it regenerated. The key part of the new research is establishing the moment when the ultraweak magnetic field regained its strength, allowing us to know when Earth’s solid inner core began to grow and estimate its age more accurately (about 550 million years ),” says Tarduno. This also allowed them to explore the fact that the current solid inner core is actually composed of two parts.
The bad news is that measuring the magnetic field directly is impossible, both because of its location (more than 6,000 km deep) and because of the extreme temperatures of the Earth’s core (approximately 6,000 degrees Celsius, more or less as hot as the surface of the Earth). sun). The good news is that the minerals that rise to the surface of the Earth contain tiny magnetic particles that can be analyzed. In this study, Tarduno and his team analyzed feldspar crystals from the rock anorthosite to better constrain the age and growth of the inner core.
Present and future of the Earth
Better understanding the dynamics and growth of the inner core and the magnetic field allows us to deepen our knowledge of our planet. «If the magnetic field had not regenerated, the atmosphere would have been unprotected from the solar wind, it would have slowly deteriorated and the Earth’s water would have been removed. The Earth probably would not have looked like today’s Mars, but we assume it would have been much drier without the protection of the shield provided by the magnetic field,” explains Tarduno. “This research really highlights the need for a habitable planet to have a growing inner core that sustains the magnetic field for its entire life, that is, many billions of years.”
A representation of the Earth, first without an inner core; second, with an internal core that began to grow, about 550 million years ago; third, with an outer and inner core, about 450 million years ago.
University of Rochester/Michael Osadciw
The problem is that, as has been seen from the European Space Agency’s (ESA) SWARM satellite constellation, the Earth’s magnetic field is gradually weakening in an area ranging from Africa to South America, a phenomenon that has been dubbed the “South Atlantic anomaly.” A priori, “this is only a concern for satellite operations (they can suffer short circuits, failures and permanent damage), but if it continues to weaken it could cause short-term ozone depletion, which would increase the risks of skin cancer in some regions,” warns Tarduno.
The magnetic field of Mars
The findings, however, not only serve to uncover Earth’s past and predict its future, but also to unravel the ways in which other planets can form magnetic shields and support the conditions necessary to support life. Researchers believe that Mars, for example, once had a magnetic field that dissipated at some point, leaving the planet vulnerable to the solar wind and the surface without an ocean.
“At the beginning of Martian history, sometime between 4.1 and 3.7 billion years ago, the Martian magnetic field died, we think because energy sources were limited to maintain the convection process,” explains Tarduno. The question is, could the Martian magnetic field regenerate, as it did on Earth, making it habitable again? “Unfortunately, on Mars, the two possible energy sources for convection: heat transfer across the Martian core-mantle boundary or chemical convection in a growing inner core, appear to lack the necessary energy, and this cannot be changed. “Still, the idea of man-made mini magnetospheres (which mimic the magnetic field) on Mars to house areas for future habitation is indeed a considerable option for the future.”
link sbobet judi bola judi bola online judi bola