The _ is the coldest layer of the atmosphere. a. troposphere b. stratosphere c. mesosphere d. thermosphere
The correct answer and explanation is:
The correct answer is c. mesosphere.
The mesosphere is the coldest layer of the atmosphere. It lies above the stratosphere and below the thermosphere, between approximately 50 to 85 kilometers above Earth’s surface. This layer experiences the lowest temperatures in the atmosphere, reaching as low as -90°C, depending on altitude and season.
The mesosphere’s cold temperatures are due to its position far from the Earth’s surface, where sunlight is less intense. Additionally, the air in this region is thin, which means it lacks the density necessary to trap heat effectively. Unlike the troposphere (the layer closest to the Earth), where weather events and heat exchange occur, or the stratosphere (where the ozone layer absorbs ultraviolet radiation from the sun and warms the atmosphere), the mesosphere does not benefit from a significant heat source.
Meteors that enter the Earth’s atmosphere typically burn up in the mesosphere due to the intense friction caused by the thin air. As these meteoroids travel at high velocities, they compress and heat up, causing them to disintegrate before they can reach the Earth’s surface. This is why we often see meteors as streaks of light in the night sky.
In the thermosphere, temperatures begin to increase again, reaching several thousand degrees Celsius as the air becomes even thinner, but due to the lack of particles to transfer this heat, the sensation of heat is not as intense as it would be at lower altitudes. The mesosphere, therefore, represents the coldest, least understood, and most dynamic layer in the Earth’s atmosphere.