Solar and Lunar Eclipses - Key Terms

Vocabulary flashcards covering solar and lunar eclipses, shadows (umbra/penumbra), paths, angular size, orbital nodes, syzygy, and related tides (spring/neap/king tides), based on the lecture notes.

Solar eclipse

An event where the Moon passes between the Sun and Earth, blocking all or part of the Sun from view.

Lunar eclipse

An event where the Earth passes between the Sun and Moon, causing the Moon to move into Earth's shadow.

Umbra

The inner, full-darkness shadow of the Moon (or Earth) during an eclipse.

Penumbra

The outer, partial-shadow region where only part of the Sun is obscured.

Total solar eclipse

When the Moon's umbra covers a location on Earth, producing full darkness for observers in the path of totality.

Partial solar eclipse

When only part of the Sun is obscured by the Moon; observers in the penumbral region see a partial eclipse.

Path of totality

The narrow track on Earth's surface where a total solar eclipse is visible.

Angular size (apparent diameter)

The apparent size of an object in the sky, determining why the Sun and Moon can look similar in size.

Lunar node

The points where the Moon's orbit crosses the Earth–Sun's orbital plane; eclipses occur when alignment happens near a node.

Syzygy

A straight-line configuration of Sun, Moon, and Earth during an eclipse.

Spring tide

A higher high tide and lower low tide when the Sun, Moon, and Earth are aligned, enhancing tidal effects.

Neap tide

A lower amplitude tide when the Sun and Moon are at right angles relative to Earth.

King tide

An especially high tide occurring when the Moon is near perigee and aligned with the Sun and Earth.

Umbra vs. Penumbra in eclipses

Umbra is full shadow with complete Sun obscuration; penumbra is partial shadow with partial Sun obscuration.