IT MAY sound like a plot from a science-fiction film but scientists believe they will soon be able to calculate the amount of fuel left within Earth.

Three new detectors coming online are expected to enable scientists to make the mind-boggling measurement within the next decade.

Earth requires fuel to drive plate tectonics, volcanoes and its magnetic field.

Like a hybrid car, it taps two sources of energy to run its “engine” – primordial from assembling the planet and nuclear from the heat produced during natural radioactive decay.

Scientists have developed numerous models to predict how much fuel remains inside Earth – and estimates vary widely – but the true amount remains unknown.

Now geologists and neutrino physicists claim they will know by 2025 how much nuclear fuel and radioactive power remain in the “tank”.

Professor William McDonough, of the University of Maryland, said: “Knowing exactly how much radioactive power there is in the Earth will tell us about Earth’s consumption rate in the past and its future fuel budget.

“By showing how fast the planet has cooled down since its birth, we can estimate how long this fuel will last.”

The researchers will rely on detecting some of the tiniest subatomic particles known to science. These antineutrino particles are byproducts of nuclear reactions within stars, supernovae, black holes and human made nuclear reactors. They also result from radioactive decay processes deep within the Earth.

Detecting them requires a device the size of a small office building, housed a mile underground. The number of detections made by scientists relates directly to the number of atoms of uranium and thorium left inside the Earth.