Microsoft Rewards Bing Homepage Quiz: What is Earth’s shadow called?
The umbra is the innermost and darkest part of the cone-shaped shadow cast by a celestial body (in this case, the Earth). The light source is completely blocked by the umbra, causing a total eclipse. The outer and much wider part of this shadow is called the penumbra. When the moon falls behind the Earth’s penumbra, the effect is much more subtle because Earth’s shadow is much fainter at that distance. You might not even notice a penumbral eclipse as the moon becomes just a shade dimmer than normal.
The correct answer to this quiz is Umbra.