In the earth’s crust, temperatures remain relatively stable throughout the year. However, beneath the crust, beneath our feet is an incredibly hot place: the core of the Earth.
From conducting plate tectonics to keeping us protected from solar radiation, the Earth’s core is not only interesting, but in part vital to life on Earth. But how long can the Earth’s core stay warm?
Keep reading to find out.
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How hot is the center of the Earth?
How hot is the Earth’s core?
Experts believe that the Earth’s core exceeds temperatures above the surface of the sun: more than 18,032 degrees Fahrenheit (10,000 degrees Celsius).
How did it get so hot in the first place?
One theory is that about 4.5 billion years ago, our Solar System consisted of a cloud of cold dust particles. This cloud of gas and dust was altered in some way and began to collapse, as gravity brought it together to form a huge rotating disk.
The center of the disk accumulated to become the Sun, and the particles in the outer rings became large balls of molten gas and liquid that cooled and condensed to take solid form.
At the same time, the surface of the newly formed planet was subjected to constant bombardment by large bodies that exploded against the planet, producing immense heat inside it, melting the cosmic dust that is there.
When the Earth was formed, it was one uniform hot rock ball. Radioactive decay and the remnants of heat from the formation of the planet caused this ball to heat up even more. Finally, after about 500 million years, the temperature of the Earth arrived at Fussion point iron: about 1,538 ° Celsius (2,800 ° Fahrenheit).
This allowed that of the Earth molten and rocky material to move even faster. Relatively floating material, such as silicates, water and even air, remained close to the planet exterior and would become the early mantle and crust. Drops of iron, nickel and others heavy metals gravity in the center of the Earth, forming the initial nucleus. This process is called planetary differentiation.
Unlike the mineral-rich crust and mantle, it is believed that the core is formed almost entirely of metal, specifically iron and nickel. While the inner core is believed to be a solid ball with a radius around it 1,260 km (760 miles), with a surface temperature of 5,700 K (5,430 ° C; 9,800 ° F); the outer core is believed to be a fluid layer about 2,400 km (1,500 miles) thick and reaching temperatures ranging from 3,000 K (2,730 ° C; 4,940 ° F) to 8,000 K (7,730 ° C; 13,940 ° F).
It is believed that the core is so hot because of the decay of radioactive elements, the excess heat from the planetary formation, and the heat released as the liquid outer core solidifies near it limit with the inner core.
So the core is incredibly hot, but how long can it stay hot?
Scientists at the University of Maryland say they will be able to answer the question in the next four years.
Leading the movement of the Earth’s tectonic plate and feeding its magnetic field requires an immense amount of power. Energy is derived from the center of the Earth, but scientists are sure that the core is cooling very, very slowly.
What makes the center of the Earth hot?
Keeping the center of the Earth warm are two sources of “fuel”: the primary energy left over from the formation of the planet and the nuclear energy that exists due to natural radioactive decay.
The formation of the Earth occurred at a time when the solar system was full of energy. During their childhood, meteorites constantly bombarded the forming planet, causing excessive amounts of frictional force. At that time, the Earth was full of volcanic activity.
How long will the Earth’s core last?
From the beginning, the planet has cooled significantly. However, there is residual heat from the Earth’s formation. Although the primordial heat has largely dissipated, another form of heat continues to heat the Earth’s mantle and crust.
There are naturally radioactive materials in large amounts in the depths of the Earth, with some residing around the crust. During the process of natural disintegration of radioactive material, heat is released.
Scientists know that heat flows from the Earth’s interior into space at a rate of approximately 44 × 1012 W (TW). What they don’t know, though, is how much heat is paramount.
The point is that if the Earth’s heat is predominantly primordial, it will cool down significantly faster. However, if heat is created primarily in part due to radioactive decay, it is likely that the Earth’s heat will last much longer.
While this sounds pretty alarming, some estimates of the Earth’s core cooling are taking it tens of billions of years, or up to 91 billion years. This is very long and in fact the Sun will probably burn long before the core, around 5 billion years.
Why is the Earth’s central temperature important?
The Earth’s core keeps the temperature stable, but more importantly, it keeps the Earth’s magnetic field in place. The Earth’s magnetic field is created by the movement of the outer core of molten metal.
This massive magnetic field extends into space and holds in place charged particles that are mostly collected from solar winds.
Fields create an impenetrable barrier in space that prevents the fastest and most energetic electrons from reaching Earth. The fields are known as the Van Allen belts and are the ones that allow life to thrive on the surface of the Earth. Without the shield of the magnetic field, the solar wind would strip the Earth’s atmosphere ozone layer which protects life from harmful ultraviolet radiation.
The collection of charged particles deflects and captures the solar wind preventing it from stripping the Earth of its atmosphere. Without him, our planet would be barren and lifeless. Mars is believed to have once had a Van Allen belt that also protected it from the deadly wind of the Sun. However, once the core cooled, it lost its shield and now remains a desolate wasteland.
How long will the Earth’s fuel last?
Today, many scientific models can estimate how much fuel is left to drive Earth’s engines. The results, however, differ greatly, making it difficult to conclude. At the moment, it is unknown how much primary and radioactive energy remains.
“I am one of those scientists who created a compositional model of the Earth and predicted the amount of fuel that is inside the Earth today,” said one of the study’s authors, William McDonough, professor of geology at the University of Maryland.
“We are in a field of riddles. At this point in my career, I don’t care if I’m right or not, I just want to know the answer. ” However, researchers believe that with modern technological advances a more accurate prediction can be made.
To determine how much nuclear fuel is left on Earth, researchers use advanced sensors to detect some of the smallest subatomic particles known to science: geoneutrinos. Geoneutrino particles are by-products generated from nuclear reactions that take place in stars, supernovae, black holes, and human-made nuclear reactors.
Detecting the amount of fuel left
Detection of antineutrine particles is an immensely difficult task. Massive detectors the size of a small office building are buried more than a mile from the earth’s crust. The depth may seem excessive; however, it is necessary to create a shield against cosmic rays that can lead to false positives.
In operation, the detector can detect antineutrinos when they collide with hydrogen atoms inside the device. After the collision, two bright flashes can be detected that unequivocally announce the event.
By counting the number of collisions, scientists can determine the number of uranium and thorium atoms left inside our planet.
Unfortunately, KamLAND detectors in Japan and Borexino in Italy only detect about 16 events a year, which makes the process slowly meticulous. However, with three new detectors projected to go online in 2020: the SNO + detector in Canada and the Jinping and JUNO detectors in China, researchers expect more 500 more events detected per year.
“Once we collect three years of antineutrino data from the five detectors, we are confident that we will have developed an accurate fuel indicator for the Earth and will be able to calculate how much fuel is left inside the Earth,” McDonough said.
The Jinping detector in China is over four times larger that all detectors so far. While the detector is large, the JUNO detector will be amazing 20 times larger what all existing detectors.
“Knowing exactly how much radioactive power there is on Earth will tell us the rate of consumption of the Earth in the past and its future fuel budget,” McDonough explained.
“By showing how fast the planet has cooled since its birth, we can estimate how long this fuel will last.”
When JUNO goes online; hopefully, in 2021: the data collected should help scientists like McDonough estimate the time left for the Earth’s core to cool. Until then, rest assured that the estimates made are likely to reach hundreds of millions, perhaps billions, of years in the future.
Therefore, there is no need to make plans to move to a new planet soon.