Final answer:
Lunar eclipses happen when the Sun, Earth, and Moon align, with the Moon passing through Earth's shadow. Total lunar eclipses occur about once every two or three years and can be seen from anywhere on Earth's night side, weather permitting.
Step-by-step explanation:
A lunar eclipse occurs when the Moon passes through the Earth's shadow, requiring a specific alignment of the Sun, Earth, and Moon. This phenomenon is visible from anywhere on Earth's night side where the sky is clear.
Lunar eclipses are relatively common events compared to solar eclipses at a given location. While total solar eclipses occur about once every 18 months somewhere on Earth, they are visible only from a very small area.
In contrast, total lunar eclipses happen, on average, about once every two or three years, but unlike solar eclipses, they are visible from an entire hemisphere.
Lunar eclipses can only occur when the Moon is in full phase, directly opposite the Sun from Earth's perspective, which makes for a dramatic viewing.
The full moon's visibility across the night side of Earth ensures a lunar eclipse is accessible to everyone in that hemisphere, weather conditions permitting. As lunar eclipses appear more frequently and can be seen without special equipment, they are often enjoyed by observers around the globe.