part 1

• The most accurate description of Earth's shape is Oblate spheroid.
• Earth is not a perfect sphere due to its rotation, resulting in a slight flattening at the poles and bulging at the equator.
• Earth's rotation causes a bulge at the equator.
• The Greek mathematician who calculated Earth's circumference using Sun angle observations is Eratosthenes.
• Anaxagoras supported the idea of a spherical Earth based on the observation the circular shadow Earth cast on the moon during a lunar eclipse.
• Anaxagoras argued that only a spherical Earth could produce a circular shadow on the moon.
• Aristotle supported a spherical Earth with the observation the variation in daylight hours at different locations.
• According to Aristotle, Earth casts a round shadow on the moon during a lunar eclipse.
• The mathematician credited with accurately calculating Earth's circumference is Eratosthenes.
• Eratosthenes measured the Earth's circumference by measuring the shadow of a stick in Alexandria and Syrene, along with knowledge of the distance between the two cities and geometry.
• Eratosthenes used measuring the shadow of a stick in Alexandria and Syrene, utilizing the distance between the two cities and applying geometric principles.
• Eratosthenes' approximate calculation for the Earth's circumference was 40,000 kilometers.
• The astronomer proposing the heliocentric model is Aristarchus.
• The comparative relationship is the Moon is closer to Earth than the Sun, and the Sun is smaller than both the Moon and Earth.
• From early astronomical observations, the conclusion is the Sun is many times farther than the Moon and much larger than Earth.
• The individual credited with measuring the length of the year accurately is Hipparchus.
• Predicting lunar eclipses contributes to enhanced accuracy in predicting celestial events.
• The primary cause of diurnal motion is earth's rotation on its axis.
• The primary cause of the annual motion of Earth is axial tilt.
• The approximate duration of Earth's complete revolution around the Sun is 365.25 days.
• The time taken for the moon to complete one full cycle of phases is 29.5 days.
• The alignment during a Full Moon is called solar eclipse.
• An eclipse is the blocking of light from one celestial body by another.