Earth's Motions, Seasons, and Solar Radiation

Vocabulary review flashcards covering Earth's rotation and revolution, solar altitude, solstices, equinoxes, insolation, and shadow variations.

Insolation

Incoming solar radiation.

Tilt of Earth's Axis

$$23.5\text{ degrees}$$

Perihelion

When Earth is closest to the Sun.

Aphelion

When Earth is farthest from the Sun.

Vertical Ray

The strongest ray of the Sun.

Altitude

The angle of an object in the sky measured from the horizon.

Zenith

The point directly over your head.

Tropic of Cancer

The latitude located at $23.5\text{ degrees north}$.

Tropic of Capricorn

The latitude located at $23.5\text{ degrees south}$.

Sun's Path Across the Sky

An arc.

Summer Solstice

Occurs on June 21 or 22; the day when the Sun reaches its maximum altitude of the year in New York.

Winter Solstice

Occurs on December 21 or 22; the day when the Sun reaches its lowest altitude of the year in New York.

Autumnal Equinox

Occurs on September 22 or 23.

Vernal Equinox

Occurs on March 19 or 20.

Equinox Daylight Duration

About $12\text{ hours}$ at every location on Earth.

Equator Daylight Duration

About $12\text{ hours}$ every day.

Aphelion Timing

Early July.

Perihelion Timing

Early January.

Sun's Vertical Ray Zone

Between the Tropic of Cancer and the Tropic of Capricorn.

Equinox Sunrise and Sunset Directions

The Sun rises due east and sets due west.

Spring to Summer Sunrise and Sunset Directions

From the first day of spring to the last day of summer, the Sun rises north of east and sets north of west.

Fall to Winter Sunrise and Sunset Directions

From the first day of fall to the last day of winter, the Sun rises south of east and sets south of west.

Solar Noon

Around $12\text{ noon}$; the time when the Sun reaches its highest altitude of the day.

Summer Solstice Daylight (Equator)

About $12\text{ hours}$.

Summer Solstice Daylight (New York)

About $15.5\text{ hours}$.

Summer Solstice Daylight (North Pole)

$24\text{ hours}$.

Summer Solstice Daylight (South Pole)

$0\text{ hours}$.

Winter Solstice Daylight (Equator)

About $12\text{ hours}$.

Winter Solstice Daylight (New York)

About $9\text{ hours}$.

Winter Solstice Daylight (North Pole)

$0\text{ hours}$.

Winter Solstice Daylight (South Pole)

$24\text{ hours}$.

Rotation

The spinning of Earth on its axis.

Earth's Rotation Period

$24\text{ hours}$.

Revolution

Earth orbiting the Sun.

Earth's Revolution Period

$1\text{ year, or } 365\frac{1}{4}\text{ days}$.

Northern Hemisphere Noon Sun Direction

South (the direction faced to see the Sun at noon).

Northern Hemisphere Noon Shadow Direction

North.

Shortest Shadow Timing

At noon.

Sunrise-to-Sunset Shadow Length Pattern

Shadows get shorter, then longer.