During a lunar eclipse the mood is not completely dark, but it is often a deep red in color. Explain this in terms of the refraction of all the sunsets and sunrises around the world.
During a lunar eclipse, the moon moves into the Earth's shadow, blocking direct sunlight from reaching it. However, the moon doesn't completely disappear because some sunlight still manages to reach it. The reason behind the deep red color observed during a lunar eclipse is explained by the phenomenon of atmospheric refraction.
To understand this, we need to consider how sunlight travels through the Earth's atmosphere. When the sun is low in the sky during sunset or sunrise, sunlight must pass through a larger portion of the Earth's atmosphere before reaching our eyes. As the light travels through the atmosphere, it interacts with molecules and particles in the air.
Now, consider all the sunsets and sunrises occurring simultaneously around the world during a lunar eclipse. Sunlight from all these locations passes through the atmosphere and undergoes scattering. This scattering process causes the shorter wavelengths of light (such as blue and green) to scatter more, while longer wavelengths (such as red and orange) are scattered less.
The scattered shorter wavelengths of light are dispersed in different directions, making the sky appear blue during the day. However, during a lunar eclipse, only the longer wavelengths (mainly red) can travel through the Earth's atmosphere and reach the moon as it lies in the Earth's shadow.
When this red light reaches the moon, it gets refracted or bent by the Earth's atmosphere and is directed towards the moon. The refracted red light is then reflected off the moon's surface, allowing us to still observe the moon during the eclipse.
The reason why the moon appears deep red rather than its usual bright white or yellow color is because the only light reaching it is red light. This red light, which has been refracted and filtered by the Earth's atmosphere, gives the moon a reddish hue during a lunar eclipse.
In summary, the deep red color observed during a lunar eclipse is a result of atmospheric refraction. When the sun is low on the horizon around the world, sunlight passes through the Earth's atmosphere and scatters shorter wavelengths, leaving mainly red light to reach the moon. This red light then undergoes refraction and reflection, resulting in the moon appearing deep red during a lunar eclipse.