Latitude, Longitude, and Earth's Motion

Vocabulary flashcards covering key terms from the lecture on latitude, longitude, rotation, orbit, eccentricity, obliquity, and seasons.

Latitude lines

Imaginary lines circling the Earth horizontally that measure position north or south of the equator; run parallel to the equator; range from -90° (South Pole) to +90° (North Pole).

Equator

The 0° latitude line that circles the middle of the Earth, equidistant from the North and South Poles.

North Pole

The point at 90°N latitude, the northernmost location on Earth.

South Pole

The point at 90°S latitude, the southernmost location on Earth.

Latitude range

The span from -90° to +90°, describing how far north or south you are from the equator.

Longitude lines

Imaginary lines running from the North Pole to the South Pole that measure east–west position relative to the Prime Meridian.

Prime Meridian

The 0° longitude line that serves as the reference for longitude, located near Greenwich, UK.

Eastern Hemisphere

The half of the Earth with longitudes from 0° to 180° East.

Western Hemisphere

The half of the Earth with longitudes from 0° to 180° West.

Northern Hemisphere

The half of the Earth north of the equator (lat > 0°).

Southern Hemisphere

The half of the Earth south of the equator (lat < 0°).

Rotation

The Earth spinning on its axis; ~24 hours per rotation; at the equator the surface moves about 1,000 mph; viewed from above the North Pole, it appears counterclockwise.

Orbit

The curved path of Earth around the Sun; shaped like an ellipse; result of gravity balancing motion; distance from the Sun changes slightly but the orbit is near circular.

Eccentricity

A measure of how circular an orbit is; Earth's orbit is low eccentricity (nearly circular).

Obliquity

The tilt of Earth's axis relative to its orbital plane, about 23.5°, which drives the seasons.

Seasons

The annual variation in sunlight and daylight caused mainly by axial tilt; Northern Hemisphere tilt toward the Sun yields summer; tilt away yields winter.

New York latitude (example)

Approximately 41.2°N, illustrating a mid-latitude location in the Northern Hemisphere.

180° Meridian (International Date Line proximity)

The meridian opposite the Prime Meridian at 180° longitude; forms a boundary between Eastern and Western Hemispheres and is near the Pacific Ocean.

Circumference at the equator

Approximately 25,000 miles; the distance around the Earth at the equator.

24-hour day

One full rotation of the Earth on its axis, defining a day.