How Much Fuel Is Left in Earth's Tank?

The remaining energy needed to drive the planet's workings will be known by 2025, scientists say.

The may seem like a strange comparison, in some ways, the Earth is a lot like a Toyota Prius.

Our planet requires energy for the internal engine that drives its various functions, ranging from tectonic plate movement and volcanic activity to its magnetic field. It gets that energy from two sources -- primordial energy left over from the Earth's formation, and nuclear energy from the heat produced by natural radioactive decay.

Scientists have wondered for a long time how much of those two sources of energy still are left in the Earth after 4.6 billion years. But now, in an article just published in Nature Scientific reports, scientists from the University of Maryland, Charles University in the Czech Republic, and the Chinese Academy of Geological Sciences say that they've developed a method that will produce a reliable estimate by 2025.

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In a new paper, a team of geologists and neutrino physicists boldly claims it will be able to determine by 2025 how much nuclear fuel and radioactive power remain in the Earth's tank. The study, authored by scientists from the University of Maryland, Charles University in Prague and the Chinese Academy of Geological Sciences, was published Friday in Nature Scientific Reports.

Within five years, scientists hope to begin using data from five underground particle detectors to determine the amount of fuel left inside the Earth. Credit: Ondřej Šrámek

To calculate the amount of fuel inside Earth, the scientists will focus upon detecting geoneutrinos, tiny particles which are byproducts of nuclear reactions within stars (including our sun), supernovae, black holes and human-made nuclear reactors.

The particles also are produced by radioactive decay deep within the Earth. Detecting geoneutrinos requires a detector the size of a small office building, buried a mile or so underground to protect it from cosmic radiation.

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Two such detectors -- one in Italy and the other in Japan -- currently exist, but another three are due to come on line in China and Canada in the next five years. One of the Chinese detectors, along the nation's southern coast, will be 20 times as big as any existing units.

"Once we collect three years of antineutrino data from all five detectors, we are confident that we will have developed an accurate fuel gauge for the Earth and be able to calculate the amount of remaining fuel inside Earth," University of Maryland geology professor William McDonough said in a press release.