Earths magnetic field is our greatest vanguard: It protects us against dangerous incoming solar radiation that, left unchecked, would make the existence of life on our world all but impossible.
And now a new analyze in the periodical Earth and Planetary Science Letters has suggested something truly remarkable: our world’s magnetic field could not be sustained without the help of the Moon. This has enormous implications for how scientists not only view planetary formation, but how they may look for life elsewhere in the cosmos.
In this scenario…the habitability on Earth appears to require the existence of a large spacecraft, wrote the team of researchers, led by Denis Andrault fromthe Universit Blaise Pascal.
The physics of Earths magnetic field is not entirely understood, but its almost certainly made within the outer core layer of countries around the world, which contains broiling, liquid metallic iron and nickel. The hot fleeing from the depths up to the surface sets up cycling convection currents within the outer core, and this movement of magnetic materials generates a powerful magnetic field that widens far beyond the surface of the planet.
When charged particles from the Sun travel towards us a phenomenon known as solar wind our magnetic field deflects these particles, preventing them from stealing away our atmosphere. Without an atmosphere, these particles would bombard Earths surface, making life far less likely to exist, if not impossible.
Earths magnetic field is one of the many reasons life is possible at the surface. Marc Ward/ Shutterstock
As this study discloses, however, theres a catch. In order for there to be convection in the outer core, there needs to be a large temperature change from the inner core to outer core, and the outer core to the mantle, the semi-molten layer that constructs up around 84 percent of Earths volume. If “were not receiving” major temperature change, there will not have been effective convection, and there will be no magnetic field.
Conventional models state that the Earth’s core needs to have very slowly cooled from 6,800 C( 12,272 F) to 3,800 C( 6,872 F) for there to be efficient convection. After carefully sifting through experimental analyzes, mathematical models, and long-touted debates about the current condition of Earths innards, the authors conclude that Earth’s depths have only cooled by around3 00 C( 572 F) since its fiery birth 4.54 billion years ago. This implies that Earths magnetic field isnt being generated by conventional convection.
So where is it coming from? Well, as it turns out, our Moon may be our silent protector. Although its weak, its gravitational pull on Earth may be responsible for not only making tides at the surface, but also deep within the outer core by mechanically stirring its liquid contents.
This tidal mechanism has already been observed causing powerful volcanism on Jupiters Io and Saturns Enceladus. On Earth, the pull of the Moon is far less powerful, but still manages to generate around a trillion watts of power within the outer core.
The new model: Over day, the convection switches from being thermally driven to being driven by the Moon’s tidal forces. Andrault et al ./ EPSL
This would be enough to mechanically force efficient convection in the outer core, meaning that our Moon working with the metal, liquid core may be responsible for sustaining our magnetic field, without which we would not exist. We found out that this possible effect of the Moon had already been proposed about 50 years ago, Andrault told IFLScience. However , no one since then had argued that this effect could be important.
The enigmatic lack of a magnetic field on Mars may be one of the reason why complex life failed to evolve on the Red Planet. Perhaps, as such studies suggests, it didnt have the right various kinds of moon watching over it.