Scientists believe that the Earth’s core, consisting primarily of iron and nickel, may be hotter than the surface of the sun, with temperatures reaching up to 5,500 degrees Celsius (9,932 degrees Fahrenheit).
Why do scientists think the Earth’s core is hotter than the sun’s surface?
The Earth’s core, located approximately 2,900 kilometers (1,800 miles) beneath the Earth’s surface, remains an elusive and challenging realm for direct exploration. Despite the inability to physically access the core, scientists have employed a combination of sophisticated techniques, including theoretical modeling and seismic studies, to gain insights into its temperature.
Scientists use the analysis of seismic waves generated by earthquakes to study the temperature of the planet’s core. By studying the behavior of these waves as they travel through different layers of the Earth, scientists can infer valuable information about the planet’s internal structure and temperature distribution.
Through seismic studies, scientists have determined that the core’s temperature increases significantly as one ventures deeper into the Earth. The most scorching temperatures are found at the boundary between the outer and inner core, approximately 3,200 miles beneath the Earth’s surface. Here, researchers estimate that the temperature reaches nearly 6,000 degrees Celsius (10,800 degrees Fahrenheit). So, if that’s the case, then the earth’s core is hotter than the sun.
Where’d that heat come from?
Interestingly, the heat in the Earth’s core does not come from the sun. The core’s exceptional temperatures are sustained by two primary heat sources. The first source of heat originates from the residual energy trapped within the Earth since its formation around 4.5 billion years ago. During the Earth’s early stages, countless collisions and mergers between rock fragments produced an immense amount of heat, some of which remains within the core to this day.
The second source of heat within the core arises from the radioactive decay of isotopes present throughout the Earth. Radioactive elements such as potassium-40, thorium-232, uranium-235, and uranium-238 release energy as they undergo decay, contributing to the overall heat budget of the core.
While the core’s temperatures may exceed those of the sun’s surface, it is important to note that the conditions in the core are drastically different. The core’s high pressures prevent its iron-nickel composition from vaporizing into gas despite the extreme temperatures.
This unique combination of heat and pressure creates an environment that sustains the core in a liquid or solid state.
Source: “How has Earth’s core stayed as hot as the sun’s surface for billions of years?” — Space.com