Umbra: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Photos and Videos

Diagram showing a lunar eclipse with the Sun on the left, Earth in the center casting a shadow, and the Moon passing through Earth's umbra (total shadow) and penumbra (partial shadow).

Diagram showing a solar eclipse, with the Sun, Moon, and Earth aligned. The Moon casts a dark umbra shadow on Earth for a total eclipse and a lighter penumbra for a partial eclipse.

What happens during a solar eclipse?

How do solar and lunar eclipses occur?

See All Videos and Images →

Topics

Eclipse Penumbra The Sun Was Eaten: 6 Ways Cultures Have Explained Eclipses Lunar eclipse Transit How Do You Tell the Difference Between Total, Annular, Solar, and Lunar Eclipses?Solar eclipse 2024 Solar Eclipse FAQ Eclipses in 2026, 2027, and 2028 How to Watch an Eclipse Safely What Causes Lunar and Solar Eclipses?

Dig Deeper: More Articles That Discuss This Topic

Eclipse: Introduction

Nicolaus Copernicus. Nicolas Copernicus (1473-1543) Polish astronomer. In 1543 he published, forward proof of a Heliocentric (sun centered) universe. Coloured stipple engraving published London 1802. De revolutionibus orbium coelestium libri vi.

All About Astronomy