wich of the following is the hottest layer of the earth? a. crust b. mantle c. inner core d. outer core
The Correct Answer and Explanation is:
The correct answer is c. inner core.
The Earth is structured in several concentric layers, and as one descends from the surface to the center, both temperature and pressure increase dramatically. This principle, known as the geothermal gradient, means that the planet’s innermost layer is by far its hottest.
While the crust is the relatively cool, solid rock on which life exists, and the mantle beneath it reaches temperatures hot enough to make rock behave like a thick, slow-moving fluid over geological time (up to 3,700°C), these layers are significantly cooler than the planet’s center. The journey continues into the outer core, a swirling layer of liquid iron and nickel with temperatures soaring between 4,400°C and 6,100°C. This liquid motion is responsible for generating Earth’s protective magnetic field.
At the very center of the planet lies the inner core, the hottest layer of all. Scientific estimates place its temperature at approximately 5,200° Celsius (9,392° Fahrenheit), a heat comparable to the surface of the sun. This extreme heat is a combination of two primary sources: primordial heat left over from the planet’s violent formation about 4.6 billion years ago, and radiogenic heat, which is continuously generated by the radioactive decay of elements like uranium and potassium within the mantle and core.
A fascinating paradox of the inner core is that despite this incredible temperature—well above the melting point of iron at surface pressure—it remains a solid sphere. This is due to the immense pressure exerted by the weight of the overlying layers, which is over 3.6 million times greater than the atmospheric pressure at sea level. This crushing pressure is so intense that it forces the iron and nickel atoms into a solid crystalline structure, preventing them from melting.thumb_upthumb_down
