Unit 5: Orbital Motions - Eclipses Practice Flashcards

Vocabulary-style flashcards covering orbital motions, eclipse definitions, orbital periods, and spatial positioning terms from the Earth and Space Science Unit 5 lecture.

Revolution

When an object travels around another one time.

Rotation

When an object spins around its axis.

Axis

A line through the center of the object.

Solar Eclipse

A phenomenon where the Moon blocks the Sun, placing Earth in the Moon's shadow.

Lunar Eclipse

A phenomenon where the Earth blocks the Sun, placing the Moon in the shadow (umbra/penumbra) of the Earth.

Blood Moon

The appearance of the Moon during a lunar eclipse when Earth's atmosphere scatters blue light and refracts red light onto the lunar surface.

Moon Phase for Solar Eclipse

Solar eclipses only occur during a New moon.

Moon Phase for Lunar Eclipse

Lunar eclipses only occur during a Full moon.

Moon's Orbital Tilt

The Moon's orbit is tilted at a angle of $5^\circ$, which explains why eclipses do not occur every month.

Moon's Axial Tilt

The tilt of the Moon's axis is $6^\circ$.

Perigee

The point in an orbit where an object is closest to the Earth.

Apogee

The point in an orbit where an object is farthest from the Earth.

Moon's Period of Revolution

The time it takes for the Moon to travel around the Earth, which is $27.3\,d$ (Earth days).

Moon's Period of Rotation at Equator

The time it takes for the moon to spin once on its axis, which is $27.3\,d$, matching its period of revolution.

Earth's Axial Tilt

The tilt of the Earth's axis, which is $23.49^\circ$.

Mean Distance from Sun (Earth)

The average distance of Earth from the Sun, which is $149.6$ million km.

Eccentricity of Orbit (Earth)

The numerical value representing how much the orbit deviates from a perfect circle, which for Earth is $0.017$.

Equatorial Diameter (Earth)

The measurement of Earth's diameter at the equator, which is $12,756\,km$.