Copy of Lesson 8/9 Study Guide

Celestial Object

An object in space that is not placed there by humans; example includes the Milky Way and its planets.

Rotation

The spin of the Earth around its axis, which takes approximately 24 hours to complete.

Revolution

The Earth's orbit around the sun, taking roughly 365.25 days to complete a year.

Axis

An imaginary line that the Earth rotates around, tilted at 23.5 degrees towards Polaris.

Orbit

The path followed around another body in space, referring to Earth's revolution around the Sun.

Elliptical Orbit

The shape of Earth's orbit around the sun; a slightly squashed circle or oval shape.

Circumpolar Stars

Stars located above and around the Earth's poles that can be seen all year round due to Earth's rotation.

Seasonal Stars

Stars visible only during certain seasons, determined by Earth's revolution around the sun.

Solstice

A time of year when the North or South pole is closest to the sun at noon; occurs twice a year.

Equinox

When day and night are approximately the same length (12 hours) in both hemispheres, occurring twice a year.

Tropic of Cancer

Located at 23.5° N latitude in the Northern Hemisphere, it receives the most direct sunlight during solstices.

Tropic of Capricorn

Located at 23.5° S latitude in the Southern Hemisphere, it receives the most direct sunlight during solstices.

Direct Sunlight

Sunlight that hits the Earth at a perpendicular angle, causing warmer temperatures.

Indirect Sunlight

Sunlight that hits the Earth at an angle, resulting in cooler temperatures.

Solar System

A celestial system that includes the sun and all objects that orbit around it, including planets.

Vernal Equinox

Marks the beginning of spring; occurs around March 20-21 in the Northern Hemisphere.

Autumnal Equinox

Marks the beginning of autumn; occurs around September 22-23 in the Northern Hemisphere.

Earth's Tilt

The 23.5° tilt of Earth's axis, crucial for the changing seasons as it varies sunlight exposure.

Ancient Civilization Calendars

Structures built by ancient civilizations to track the sun's position and create reliable calendars.

Summer Solstice

Occurs on June 21 in the Northern Hemisphere; the longest day of the year with maximum sunlight.

Winter Solstice

Occurs on December 21 in the Northern Hemisphere; the shortest day of the year with minimum sunlight.

Orbital Plane

The flat surface defined by the orbit of an object in space, such as Earth around the sun.

Seasonal Changes

Variations in climate and environment as a result of Earth's tilt and its orbit around the sun.