There is a sphere of iron at the center of the Earth. Scientists believe that the birth of the inner core half a billion years ago may have played a key role in the evolution of life on Earth.

Their argument is that the planet's magnetic field was faltering at that time. Life on the surface is protected by repelling radiation and particles from the sun.

It had fallen to a fraction of its strength before it regained it's strength. The proliferation of complex multicellular life on the Earth's surface occurred in the wake of this planetary reboot. The first major animal groups appeared in the fossil record. Scientists are linking it to events at the center of the Earth.

The planet is made of spheres. There is a layer of rock that is 70 km thick. The mantle is made up of 3,000 km of silicates. There is a sphere of solid iron inside the outer core. It is growing at an annual rate of about a millimetre.

John Tarduno is a professor of geophysics at the University of Rochester, New York. The ability to generate a magnetic field was collapsing before the explosion.

Tarduno's team analyzed rocks in Quebec and found that the Earth's magnetic field was less than 10% of its strength. It is argued that the Earth's magnetic field is caused by the loss of heat from the core.

The core solidified at its center, which had profound consequences. The strength to the planet's magnetic field was restored by it. According to Tarduno's research, the formation of the inner core took place just before the Cambrian explosion.

The birth of the inner core had been shrouded in mystery. It has been a sphere of iron for half a billion years. It is the most metallic place on the planet, and it has had a big impact on the surface.

Rock formations capped with snow, surrounded by forests

A view of snow-covered Stolby nature reserve, in Krasnoyarsk, Russia. These rock pillars date from the Cambrian period, more than 600m years ago, to the Carboniferous period. Photograph: Anadolu Agency/Getty Images

It gave our world a magnetic field. The consequences of this loss can be seen in the observations of other worlds. Mars lost its magnetic field 4 billion years ago Without protection from the solar wind, the Martian atmosphere was driven off into space and left without water.

If Earth hadn't had a magnetic field, it would have lost more water than it has now. The one we live in today would have been a lot more dry.

The rebirth of Earth's magnetic field would have an effect on the evolution of life, according to aphysicist. I don't believe that the return of Earth's magnetic field can be connected. We can't say what happened as of right now. That needs to be studied a bit more.