termosfääristä

The termosfääristä, often translated as thermosphere, is the fourth layer of Earth's atmosphere, situated above the mesosphere and below the exosphere. It begins at an altitude of about 80-85 kilometers (50-53 miles) above sea level and extends upwards to approximately 600-1000 kilometers (370-620 miles).

A defining characteristic of the thermosphere is its significant temperature increase with altitude. Unlike the layers below it, where temperatures generally decrease with height, the thermosphere's temperature rises dramatically due to the absorption of high-energy ultraviolet and X-ray radiation from the Sun by the sparse gas molecules present. Temperatures in the thermosphere can reach thousands of degrees Celsius, though the concept of temperature here is different from what we experience at ground level because the air is so thin; there are too few particles to transfer significant heat to an object.

This layer is home to the International Space Station and many other satellites, as they orbit within its relatively low-density environment. The thermosphere also plays a crucial role in phenomena like the aurora borealis and aurora australis (northern and southern lights). These spectacular displays occur when charged particles from the Sun, guided by Earth's magnetic field, collide with gas molecules in the thermosphere, causing them to emit light. The upper part of the thermosphere, where atoms and molecules begin to escape into space, transitions into the exosphere.