New Research has Found ：The Earth’s Core is Only a Billion Years Old

The young core

This conductivity data allowed the researchers to calculate the amount of heat-cooling energy in the core that could be used by a generator. They found that the geodynamo draws about 10 terawatts of energy from the cooled core -- a little more than one fifth of the heat dissipating through the earth’s surface into space.

Lin said, once the loss of energy has been calculated, the researchers can calculate the age of the earth’s inner core. Getting to know the rate of energy loss, researchers can calculate how long it took to get from a blob of molten iron to a solid core the same size as it is today.

Lin said, “the result with the 1 billion-1.3 billion-year-old age suggests that the earth core is “actually relatively young.”

This age of estimate is no younger than other estimated ages, such as a study published in Nature in 2016, which used similar methods to find the core just 70 million years old. Lin says the new experiment uses more reliable methods to deal with the pressures and temperatures generated in the core, making that younger estimate less likely.

According to a study in “Nature” in 2015, ancient lodestones reveal that earth’s magnetic field suddenly strengthened 1.5 billion or 1 billion years ago. Our new estimates are also consistent with this evidence, Lin says, because crystallization in the inner core “strengthens” the magnetic field.

Lin says, questions remain about the way heat moves around the earth’s core. Unlike the samples they tested, the core is not full of iron -- it also contains the lighter elements carbon, hydrogen, oxygen, silicon, and sulphur. However, the proportion of these light elements is unknown, so it is difficult to know how they change the conductivity of the inner core. That is what Lin and his team are currently working on.

Lin says, “We are trying to understand how the existence of these light elements affects iron’s heat-conducting materials under high pressures and temperatures.