The study that affirms that the interior of the Earth is cooling faster than expected (and the consequences that this implies for the evolution of the planet)

If you have ever been told “I feel like things are getting cold”, you know something is wrong.

The same happens with the interior of planet Earth, which has a core that has remained extremely hot for more than 4.5 billion years, but slowly and inevitably cools.

Earth’s core is key to life, so if it ever goes dark, the planet itself will turn into a gigantic cold and inert rock.

Now, in recent research, a team of scientists has calculated that cooling is happening. faster than was believed.

This cooling happens on scales of billions of years, so as fast as it was, none of us will be alive to see what that cold would be like. death of the planet

Experts, however, agree that investigating these natural processes is key to better understanding the evolution of the earth and the phenomena that affect life on the planet.

What is this cooling and how did they discover that it is faster than previously thought?

• The strange behavior of the Earth’s core that scientists do not know how to explain

The interior of the Earth

The core of the Earth is a region located almost 3,000km deep of the earth’s crust, with a radius of 3,500 km.

Core temperatures can fluctuate between 4,400°C and 6,000°C, a temperature similar to that of the Sun.

The inner core is a solid spherecomposed mostly of iron.

The outer core is made of a malleable liquid composed of iron and nickel.

It is in the outer core that the magnetic field of the Earth, which protects the planet from dangerous solar winds.

The colossal amount of thermal energy that emanates from the interior of the planet sets in motion phenomena such as plate tectonics and volcanic activity.

In addition, a process occurs at the borders of the nucleus that was the key to the new study: mantle convectionwhich refers to heat transfer from the core to the mantle.

• Why is the Earth “shining” less in recent years?

The core border

Scientists don’t know precisely how long it will take for Earth to cool to the point that stop natural phenomena that drives the nucleus, or that the magnetic field disappeared, for example.

A team from the Swiss Federal Institute of Technology in Zurich (ETH) and the Carnegie Institution of Science in the United States believes that the key to solving this mystery lies in the minerals that carry heat from the core to the mantle.

This border region is made up primarily of a mineral called bridgmanitewhich has a crystal structure and can only exist under great pressure, from about 700 km deep.

There is no technology that allows dig and study minerals at that depth, so ETH professor Motohiko Murakami designed an experiment to simulate those conditions in the laboratory.

pressure and temperature

Murakami and his colleagues devised a method to measure the amount of heat which can conduct bridgmanite.

What they did was make a bridgmanite diamond from the elements that compose it.

They then inserted the crystal into a device that simulates the pressure and temperature prevailing inside the Earth.

Inside the device, they shot laser beam pulses that irradiated and heated the mineral, in a process known as “optical absorption measurement”.

That way, they could see how the mineral reacted at different pressures and temperatures.

“This measurement system allowed us to show that the thermal conductivity of bridgmanite is approximately 1.5 times larger than assumedMurakami says in a statement.

According to the researcher, this indicates that the heat flux from the core to the mantle is also greater than previously thought.

The result of the experiment suggests that the faster heat is transferred from the core to the mantle, the faster heat is lost in the corewhich accelerates the cooling of the Earth.

Furthermore, the authors believe that this cooling would change the composition of the minerals in the mantle.

When bridgmanite cools, it turns into another mineral called post-perovskite.

Post-perovskite conducts heat very more efficient than bridgmanite, so as core-mantle boundary bridgmanite converts to post-perovskite, the cooling of the Earth would be even fasterindicate the researchers.

Destined to die?

This faster cooling can have several consequences, the study authors note.

On the one hand, it can cause tectonic plateswhich are kept moving by the flow of the mantle, slow down faster than expected.

“Our results could give us a new perspective on the evolution of the Earth’s dynamics,” explains Murakami.

Murakami, however, cautions that at this point they can’t estimate how long that cooldown will take. would stop activity in the mantle.

To do this, they need to better understand the dynamics of the mantle and the reactions of the elements that compose it.

“This study offers a new view of the main geological process that affects the rocky planets (like the Earth): the speed at which they cool down, “Paul Byrne, professor of Planetary and Earth Sciences at Washington University in San Luis, United States, who was not involved in the investigation, tells BBC Mundo.

“Mars, Mercury, and the Moon have cooled so much over the past 4.5 billion years that, geologically speaking, they are essentially inert“.

Therefore, unlike the Earth, Mars, Mercury and the Moon do not have tectonic plates, explains the expert.

“Is that the destination What lies ahead for our world?” asks Byrne.