Earth's axis is the imaginary line that runs through the North and South Poles, around which the planet rotates.

Earth's rotation period, also known as a sidereal day, is approximately 23 hours 56 minutes.

Earth's rotation on its axis causes different parts of the planet to face the Sun at different times, resulting in the day and night cycle.

Earth's revolution is the path it takes around the Sun, completing one full orbit in approximately 365.25 days.

Earth's revolution period, also known as a tropical year, is approximately 365.25 days.

Earth's revolution around the Sun causes different parts of the planet to receive varying amounts of sunlight throughout the year, resulting in seasons.

Earth's axis is tilted at an angle of approximately 23.5 degrees with respect to its orbital plane.

The tilt of Earth's axis causes different latitudes to receive varying amounts of sunlight throughout the year, resulting in variations in temperature and seasons.

The zenith is the highest point in the sky directly overhead.

The nadir is the lowest point in the sky directly opposite the zenith.

The equator is the line that divides the Earth into the Northern and Southern Hemispheres.

The Tropic of Cancer and Tropic of Capricorn mark the northernmost and southernmost points where the Sun can be directly overhead, respectively.

The equinoxes are the two days of the year when the Sun is directly overhead at the equator, resulting in equal day and night.

The solstices are the two days of the year when the Sun is at its highest and lowest points in the sky, resulting in the longest and shortest days, respectively.

Perihelion is the point in Earth's orbit when it is closest to the Sun.