Radiation

Front

Rotation Noun

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[roh-tay-shun]

Back

Rotation

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The spinning of a celestial body, such as a planet, on its own internal axis, which causes day and night.

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Example: Earth's rotation on its axis causes day and night, as shown by the division of light and shadow.

Front

Revolution Noun

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[rev-uh-loo-shun]

Back

Revolution

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The movement of one celestial body in a curved path, or orbit, around another celestial body, defining a year.

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Example: Earth's revolution around the Sun defines a year, shown with arrows and distances.

Front

Axis Noun

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[ak-sis]

Back

Axis

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An imaginary line passing through the center of a planet, from the North to South Pole, around which it rotates.

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Example: The image shows Earth's axis as a dashed line, demonstrating how the planet rotates around it.

Front

Orbit Noun

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[or-bit]

Back

Orbit

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The curved path an object in space follows as it travels around another object due to gravitational attraction.

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Example: The image shows the Moon's orbit around Earth, highlighting the curved path due to gravity.

Front

Tilt Noun

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[tilt]

Back

Tilt

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The angle of a planet's rotational axis relative to its orbital plane, which is the primary cause of seasons.

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Example: Earth's tilt causes different parts of the planet to receive sunlight, resulting in day and night.

Front

Solar energy Noun

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[soh-ler en-er-jee]

Back

Solar energy

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Radiant energy, including both heat and light, that is emitted by the Sun and travels through space.

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Example: The image shows solar energy as waves traveling from the Sun to Earth, illustrating radiant energy.

Front

Summer Solstice Noun

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[suhm-er sol-stis]

Back

Summer Solstice

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The point in the year when a hemisphere is tilted most directly toward the Sun, resulting in the longest day.

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Example: Earth's tilt towards the Sun during the summer solstice results in the longest day of the year.

Front

Winter Solstice Noun

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[win-ter sol-stis]

Back

Winter Solstice

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The point in the year when a hemisphere is tilted most directly away from the Sun, resulting in the shortest day.

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Example: Earth's tilt causes one hemisphere to receive less sunlight, creating the shortest day during the Winter Solstice.

Front

Equinox Noun

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[ee-kwi-noks]

Back

Equinox

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One of two days a year when the Sun is directly over the equator, causing nearly equal hours of day and night.

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Example: The image shows the Earth during an equinox, with sunlight directly over the equator, creating equal day and night.

Front

North Star Noun

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[north star]

Back

North Star

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The star (Polaris) located almost directly above Earth's North Pole, serving as a fixed reference point in the sky.

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Example: The image shows Polaris (North Star) above Earth's North Pole, using Ursa Major and Ursa Minor as guides.