Earth's Rotation, Translation, and Seasons

• Earth is a slightly tilted, rocky body with a spherical shape, flattened at the poles.
• Its diameter measures approximately 12,700 kilometers.
• Earth is in constant motion, performing rotation and translation movements.

Rotation

• Earth rotates on an imaginary axis passing through the poles.
• A complete rotation takes 24 hours, defining a day.
• The rotation is responsible for the cycle of day and night.

Translation

• Earth revolves around the Sun.
• The translation causes the seasons, each lasting about three months: winter, spring, summer, and autumn.
• A complete translation takes 365 days and about 6 hours, defining a year.
• The extra 6 hours accumulate, resulting in a leap year every four years, with an additional day in February.

Seasons

• Seasons arise from Earth's changing position during its translation around the Sun and the tilt of its rotation axis.
• This causes varying angles and intensity of sunlight throughout the year.
• Seasons are opposite in the northern and southern hemispheres.
• Summer (June 21 to September 21): Rays are almost perpendicular, heating the surface more intensely, temperatures are higher, and days are longer than nights.
• Autumn (September 21 to December 21): Rays are oblique, Earth receives less heat, temperatures are mild, and day and night are of equal length.
• Winter (December 21 to March 21): Rays are very oblique, Earth receives little heat, temperatures are low, and nights are longer than days.
• Spring (March 21 to June 21): Rays are slightly oblique, Earth receives more heat, temperatures are mild, and day and night are of equal length.
• Translation causes the year and the seasons.

The Moon

• The Moon is the Earth's only satellite, a rocky sphere without an atmosphere or hydrosphere.
• Its surface is marked by numerous craters from meteorite impacts.
• The Moon undergoes rotation on its axis and translation around Earth.
• Both movements take approximately 29 and a half days, so we always see the same side of the Moon from Earth.

Lunar Phases

• Lunar phases are due to its movement.
• New Moon: The moon is not visible.
• Waxing Crescent: The illuminated area is growing (shaped like a D).
• Full Moon: The entire moon is illuminated.
• Waning Crescent: The illuminated area is decreasing (shaped like a C).

Solar Eclipses

• Solar eclipses occur when the Moon passes between the Sun and Earth, almost entirely blocking the Sun.

Tides

• Tides are the rise and fall of sea levels, occurring approximately every six hours.
• Tides result from the gravitational pull between the Moon and Earth.
• High tide occurs when the Moon is closest to Earth, and low tide occurs when the Moon is farthest away.