Temperatures on the Earth’s crust remain relatively stable throughout the year. But beneath the crust, beneath our feet, is an incredibly hot place – the core of the Earth!
From powering plate tectonics to protecting us from solar radiation, Earth’s core is not only interesting, but partly vital to life on Earth. But how long can the core of the Earth stay warm?
Read on to find out.
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How hot is the center of the Earth?
How hot is the core of the earth?
Experts believe that the Earth’s core exceeds temperatures higher than 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 our solar system was made up of a cloud of cold dust particles about 4.5 billion years ago. This cloud of gas and dust was somehow disrupted and started to collapse, as gravity pulled everything together and formed a huge spinning disk.
The center of the disk grew to become the sun, and the particles in the outer rings turned into large fiery balls of gas and molten liquid that cooled and condensed to form a solid.
At the same time, the surface of the newly formed planet was constantly bombarded by large bodies striking the planet and producing enormous heat within, melting the cosmic dust found there.
When the earth was formed, it was one uniform ball of hot rock. Radioactive decay and the leftover heat from the planet’s formation caused this ball to get even hotter. Finally, after about 500 million years, the Earth’s temperature reached the melting point iron – about 1,538 ° Celsius (2,800 ° Fahrenheit).
This allowed the earth molten, rocky material to move even faster. Relatively floating material, such as Silicates, water, and even air remained close to the planet’s exterior and would become the early mantle and crust. Droplets of iron, nickel and others heavy metals attracted to the center of the earth, forming the early nucleus. This process is called planetary differentiation.
Unlike the mineral-rich crust and mantle, the core is believed to consist almost entirely of metal – particularly iron and nickel. While the inner core is considered a solid ball with a radius of round 760 miles (1,220 km), with a surface temperature of 5,700 K (5,430 ° C; 9,800 ° F); the outer core is believed to be a liquid layer about 2,400 km (1,500 miles) thick and reaches temperatures from 3,000 K (2,730 ° C; 4,940 ° F) to 8,000 K (7,730 ° C; 13,940 ° F).
The core is thought to be so hot because of the decay of radioactive elements, leftover heat from planetary formation, and heat released when the liquid outer core solidifies are near border with the inner core.
So the core is incredibly hot, but how long can it stay warm?
Scientists at the University of Maryland claim they can answer the question within four years.
Controlling the movement of the Earth’s tectonic plate and driving the magnetic field requires an enormous amount of force. The energy comes 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”: primal energy left over from the formation of the planet and nuclear energy that exists as a result of natural radioactive decay.
The formation of the Earth took place at a time when the solar system was buzzing with energy. During childhood, meteorites constantly bombarded the forming planet, creating excessive frictional force. At the time, the Earth was full of volcanic activity.
How long will the Earth’s core last?
Since the beginning, the planet has cooled significantly. However, residual heat from the formation of the earth remains. Although the primordial heat has largely disappeared, another form of heat continues to heat the mantle and crust.
There are naturally radioactive materials in large quantities deep in the Earth, and some are around the crust. Heat is released during the natural decay of the radioactive material.
Scientists know that heat flows from the interior of the Earth into space at a speed of approx 44 × 1012 W (TW). What they don’t know, however, is how much of the heat is paramount.
The problem is, if Earth’s heat is predominantly primordial, it will cool down significantly faster. However, if the heat is largely caused by radioactive decay, Earth’s heat will likely last much longer.
While that sounds pretty alarming, some estimates for the cooling of the Earth’s core point to this tens of billions of years, or even 91 billion years. That’s a really long time, and in fact, the sun will probably burn out long in front of the core – nearby 5 billion years.
Why is Earth’s core temperature important?
The Earth’s core keeps the temperature stable, but more importantly, it holds the Earth’s magnetic field in place. The Earth’s magnetic field is created by the movement of the outer molten metal core.
This enormous magnetic field extends into space, holding in place charged particles that are usually collected by the solar winds.
The fields form an impenetrable barrier in space that prevents the fastest, most energetic electrons from reaching Earth. The fields are known as the Van Allen Belts and allow life on the Earth’s surface to thrive. Without the shield of the magnetic field, the solar wind would be the Earth’s atmosphere ozone layer that protects life from harmful ultraviolet radiation.
The collection of charged particles deflects and traps the solar wind, preventing it from stripping Earth’s atmosphere. Without it, our planet would be sterile and lifeless. It is believed that Mars once had a Van Allen belt that also protected it from the deadly winds of the sun. Once the core cooled, it lost its shield and now it remains a desolate wasteland.
How Long Does Earth’s Fuel Last?
Currently, many scientific models can estimate how much fuel is left to power Earth’s engines. However, the results differ greatly, making it difficult to reach a definitive conclusion. It is currently unknown how much primordial and radioactive energy is left.
“I am one of those scientists who created a compositional model of the Earth and predicted the amount of fuel in the Earth today,” said one of the study’s authors, William McDonough, a professor of geology at the University of Maryland. .
‘We’re in a gambling field. At this point in my career I don’t care if I’m right or wrong, I just want to know the answer. However, researchers believe that with modern technological advancements, a more accurate prediction can be made.
To determine how much nuclear fuel is left in Earth, the researchers use sophisticated sensors to detect some of the smallest subatomic particles known to science – geoneutrinos. Geoneutrino particles are the byproducts generated by nuclear reactions that take place in stars, supernovae, black holes and man-made nuclear reactors.
Detect how much fuel is left
Tracking down anti-neutrino particles is a very difficult task. Huge detectors the size of a small office building are buried more than 0.6 miles (a kilometer) deep in the Earth’s crust. The depth may seem exaggerated; However, it is necessary to create a shield against cosmic rays that can result in false positives.
In operation, the detector can detect anti-neutrinos when they collide with hydrogen atoms in the device. After the collision, two bright flashes can be detected, unambiguously announcing the event.
By counting the number of collisions, scientists can determine the number of uranium and thorium atoms left on our planet.
Unfortunately, KamLAND detectors in Japan and Borexino in Italy only detect about 16 events per year, making the process extremely slow. With three new detectors expected to come online in 2020 – the SNO + detector in Canada and the Jinping and JUNO detectors in China – researchers expect more than 500 more events detected per year.
“Once we have collected three years of anti-neutrino data from all five detectors, we are confident that we have developed an accurate Earth fuel gauge and will be able to calculate the amount of fuel remaining in the Earth,” said McDonough.
The Jinping detector in China is over four times the size than all detectors so far. Although the detector is large, the JUNO detector will be stunning 20 times bigger then all existing detectors.
“If we know exactly how much radioactive power there is in the Earth, we will learn more about the Earth’s past consumption and future fuel budget,” McDonough explains.
“By showing how quickly the planet has cooled since birth, we can estimate how long this fuel will last.”
When JUNO comes online; hopefully in 2021 – the data collected should help scientists like McDonough estimate how long the Earth’s core will have to cool. Until then, you can be sure that any estimates made are likely to amount to hundreds of millions, perhaps billions of years in the future.
So there is no need to make plans to move to a new planet anytime soon.