In Earth's atmosphere, many artificial satellites are placed in orbit within which layer because it extends to high altitudes and contains the ionosphere?

Introduction / Context:
Earth's atmosphere is divided into several layers based on temperature changes with height: troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Artificial satellites orbit Earth at various altitudes, and many of them, especially low Earth orbit and communication satellites, operate in the higher layers. Geography and general science exams frequently ask which atmospheric layer houses many satellites.

Given Data / Assumptions:

• The question refers to many satellites being placed in orbit.
• We assume common school level classification of atmospheric layers.
• We also assume familiarity with the term ionosphere, which lies mainly within the thermosphere.
• We ignore very high orbits that extend beyond the conventional atmosphere.

Concept / Approach:
The thermosphere extends from roughly 80 kilometres to several hundred kilometres above Earth's surface and overlaps with the ionosphere, where gases are ionised by solar radiation. Many low Earth orbit satellites, including some communication and weather satellites, operate within these altitudes. The stratosphere sits below the mesosphere and contains the ozone layer but relatively few satellites. The exosphere is the outermost layer, but in school level descriptions, the thermosphere is usually highlighted as the layer where many satellites are found.

Step-by-Step Solution:
Step 1: Recall the basic vertical order of atmospheric layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere.Step 2: Identify which layer is commonly associated with the ionosphere and satellite orbits in textbooks, which is the thermosphere.Step 3: Consider option A, thermosphere, which explicitly states it includes much of the ionosphere.Step 4: Option D, stratosphere, is better known for containing the ozone layer and commercial air traffic, not satellite orbits.Step 5: Options B, C, and E are either incorrect descriptions or nonstandard terms at this level, so option A is the best answer.

Verification / Alternative check:
School geography chapters on atmosphere typically state that radio waves are reflected in the ionosphere, which lies within the thermosphere, and that many communication satellites occupy orbits in this region. Some diagrams also show satellites orbiting above the mesosphere, within the thermosphere. This teaching emphasis supports the choice of thermosphere as the correct layer for many satellites.

Why Other Options Are Wrong:
Option B, exosphere, is the outermost, very thin region where a few satellites may travel, but the question phrase many satellites is usually linked with the thermosphere in textbooks. Option C, orthosphere, is not a standard term in basic atmospheric science. Option D, stratosphere, is important for ozone concentration and aircraft flight but not for most satellite orbits. Option E, troposphere, is the lowest layer where weather phenomena occur; satellites orbit far above it.

Common Pitfalls:
Students sometimes mix up thermosphere and exosphere because both are high altitude layers. Another confusion arises when they assume that the layer containing aircraft must also contain satellites. Remembering that satellites are much higher than airplanes, and that the ionosphere and many orbits are within the thermosphere, helps to select the correct layer in this question.

Final Answer:
Many artificial satellites are placed in orbit within the Thermosphere, which includes much of the ionosphere.