Week 6- Earth, Sun, and Moon

Geocentrism–the theory that Earth is at the center of the solar system, and the Sun and other planets revolve around it

Heliocentrism–the theory that the Sun is at the center of the universe and Earth orbits the Sun.

Equinoxes (which sounds like the word equal) marks the day in which all of Earth receives an equal amount of sunlight–12 hours. This equal amount of sunlight occurs when the Equator is directly in line with the Sun. 

The Spring Equinox happens around March 20th and the Autumn Equinox happens around September 23rd each year.

Solstices mark the days of the year in which a hemisphere receives the least amount of sunlight (aka the shortest day of the year) and the most amount of sunlight (aka the longest day of the year). These days occur when one of the tropic lines is directly in line with the Sun.

Winter Solstice= Day with LEAST amount of sunshine

Summer Solstice= Day with MOST amount of sunshine

Eclipses: when light is blocked. There are two types of eclipse that we can see on Earth: solar eclipses and lunar eclipses.

Solar Eclipse: Sun is being blocked–this happens when the Moon perfectly crosses between Earth and the Sun. A solar eclipse always occurs during a new moon.

Lunar Eclipse: Moon is blocked when it passes through Earth’s shadow. When the Moon is in this position, the Sun’s light cannot reach it. A lunar eclipse always occurs during a full moon.

Phases of the Moon

New: The Moon’s face is not visible from Earth

Crescent: Between a new moon and a quarter moon

Quarter: From Earth, we can see half of the moon’s face which is a quarter of the entire moon

Gibbous: Between a quarter moon and a full moon

Full: All of the Moon’s face is visible from Earth

For the first half of this cycle, the visible part of the Moon waxes or grows larger. After reaching a full moon, the Moon wanes or grows smaller for the second of the cycle.

Nearside of the Moon: Side we can see from Earth

Farside of the Moon: Side that we can't see from Earth