Explanation:

**Atmospheric Refraction: Why Stars Appear Higher in the Sky**

When we observe the night sky, we often notice that stars appear to be higher in the sky than they actually are. This phenomenon can be explained by the concept of atmospheric refraction.

**Definition of Atmospheric Refraction:**

Atmospheric refraction is the bending of light as it passes through the Earth's atmosphere. When light enters the Earth's atmosphere from space, it encounters different layers of air with varying densities. This causes the light to change direction slightly, leading to the apparent displacement of celestial objects like stars.

**Causes of Atmospheric Refraction:**

There are several factors that contribute to atmospheric refraction, such as:

1. **Variation in Air Density:** The Earth's atmosphere is composed of air molecules that are not evenly distributed. The density of air decreases as we move higher up in the atmosphere. This variation in air density causes light to bend as it passes through different layers of the atmosphere.

2. **Change in Refractive Index:** The refractive index of air changes with altitude, temperature, and pressure. Refractive index is a measure of how much light bends when it passes from one medium to another. As the refractive index of air changes with different atmospheric conditions, the path of light is altered, leading to the apparent displacement of celestial objects.

3. **Angle of Incidence:** The angle at which light enters the Earth's atmosphere also affects the degree of atmospheric refraction. When light enters the atmosphere at a low angle, it passes through a larger portion of the atmosphere, resulting in a greater bending of light. This is why stars near the horizon appear to be more elevated than they actually are.

**Effects of Atmospheric Refraction on Stars:**

The phenomenon of atmospheric refraction causes stars to appear higher in the sky than their true position. This is because the light coming from the stars bends as it passes through the Earth's atmosphere. The degree of bending depends on the density of air, refractive index, and angle of incidence.

As a result, stars near the horizon experience more atmospheric refraction compared to stars directly overhead. The bending of light makes the stars appear higher in the sky, creating an illusion of their elevated positions.

**Conclusion:**

In conclusion, stars appear higher in the sky than they actually are due to the phenomenon of atmospheric refraction. The bending of light as it passes through the Earth's atmosphere causes the apparent displacement of celestial objects. This effect is influenced by factors such as variation in air density, change in refractive index, and the angle of incidence. Understanding atmospheric refraction helps us explain the observed positions of stars and other celestial objects in the night sky.