The terminator is a moving border that wraps around the Earth as it spins, creating the illusion of the Sun rising and setting. At any moment, one half of the Earth is bathed in sunlight, while the other is in shadow, and the terminator is the glowing boundary in between. But it’s not a hard line. It’s a gradient of light, softened by Earth’s atmosphere. This is why we get beautiful sunsets and sunrises, with the sky glowing long before or after the Sun is visible. Some Facts About The Terminato