Start of a total lunar eclipse. Image 4 of 12. A total lunar eclipse occurs when the Earth moves between the Sun and the Moon. At totality, the light from the Moon (sunlight reflected from the Moon after passing through the Earth's atmosphere) turns orange due to shorter wavelengths, such as blue light, being scattered more in Earth's atmosphere than longer wavelengths, such as red light. A total lunar eclipse typically lasts for 4-6 hours. For the 12 images from start to totality for this lunar eclipse, see images C047/6661 to C047/6672. For montages showing the sequence, see images C047/6659 and C047/6660.