The dark shadow caused by the moon on Earth is called the umbra.

This is the darkest part of the moon's shadow, where the sun's light is completely blocked. It's only visible during a solar eclipse.

Here's a breakdown:

* Umbra: The darkest part of the moon's shadow.

* Penumbra: The lighter part of the moon's shadow, where some sunlight reaches.

* Antumbra: A region of the moon's shadow beyond the umbra, where only a partial eclipse is visible.

Let me know if you have any other questions about eclipses or anything else!