The Earth’s core is as hot as the sun’s surface, according to a new study published in the journal Science. The study took measurements that suggest the planet’s inner core is much higher than prior measurements suggested.
The new research puts the temperature at 6,000 degrees Celsius, or as hot as the surface of the sun. The Earth’s core is solid crystallized iron, surrounded by liquid. However, the temperature at which the crystal can form has been hotly debated.
Measurements taken of iron’s “melting curves” in the early 1990s suggested that the planet’s core temperature is about 5,000 degrees Celsius. However, experiments outlined in the new study used x-rays to probe tiny samples of iron at massive pressures to examine ho iron crystals can form and melt.
Seismic waves that are captured after earthquakes around the world can also give a lot of information as to what thickness and density each layer of the Earth is. However, they do not give an indication of temperature. The measurement has to be either worked out in computer models simulating the inside of the earth, or in the lab.
Agnes Dewaele of the French research agency CEA and a co-author of the new research, stated of the 1990s measurements:
“It was just the beginning of these kinds of measurements to they made a first estimate … to constrain the temperature inside the Earth. Other people made other measurements and calculations with computers and nothing was in agreement. It was not good for our field that we didn’t agree with each other.”
But scientists were able to come up with the new conclusion using an experimental setting and x-ray defraction. They saw how iron crystals were able to hold under extreme pressure. They then extrapolated their results to higher temperatures, concluding that the melting point of iron is at 330 gigapascal 00 though to be the same as the temperature of the boundary of the Earth’s inner core.
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