Final answer:
The middle layer of the Earth's atmosphere is the mesosphere, which lies between the stratosphere and the thermosphere.
Step-by-step explanation:
The middle layer of the Earth's atmosphere is the mesosphere. This layer extends from the top of the stratosphere at about 50 kilometers (31 miles) above the Earth's surface to about 85 kilometers (53 miles) high. In the mesosphere, meteors burn up upon entry from outer space, making it a vital shield for our planet. Above the mesosphere is the thermosphere, where phenomena such as auroras occur, and satellites orbit the Earth. The exosphere is the outermost layer and may extend up to 10,000 km (6,200 mi) above the Earth. It's important to note that the stratosphere is where the ozone layer is located, which absorbs ultraviolet B rays, providing a protective layer from harmful UV radiation.