Week 6: Earth Sun Moon

 Lab 

1. How do the phases of the moon occur? 

- Not sure about this, but I think it has something to do with the way the Earth orbits. 

2. What causes the seasons? 

- I think that seasons are caused by the way the Earth spins on its axis, and how it moves around the Sun. 

3. What causes a lunar eclipse? 

- This has something to do with shadows I think but I'm not positive. 

Textbook

  •  Heliocentrism vs. Geocentrism 
    • Geocentrism: the theory that Earth is at the center of the solar system
      • Sun and other planets revolve around it 
    • Heliocentrism: the theory that the Sun is at the center of the universe 
      • Earth orbits the Sun 
  • Root words 
    • Geo: earth
    • Centr: center
    • Helio: sun 
  • Equinoxes
    • Mark the day in which all of Earth receives an equal amount of sunlight - 12 hours 
    • Spring equinox: March 20th 
    • Autumn equinox: September 23rd 
  • Solstices 
    • Winter solstice: usually around Dec. 21
    • Summer solstice: usually around June 21
    • Mark the days of the year where 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 occur when one of the tropic lines are directly in line with the sun 
    • N. Hemisphere: Winter solstice occurs when Tropic of Capricorn (southern tropic line) is in line with the Sun 
    • Summer solstice occurs when Tropic of Cancer (Northern tropic line) is in line with the Sun 
  • Eclipses
    • Happen when light is blocked
    • Solar & lunar eclipses
    • Solar eclipse: In a solar eclipse the 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: In a lunar eclipse, the 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.
  • Seasons
    • Plane of the Ecliptic: Earth orbits in the same plane as the other planets in our solar system
    • If a hemisphere is tilted towards the sun - gets more sunlight - warms up - aka summer
    • If a hemisphere is tilted away from the sun - gets less sunlight - cools down - aka winter
    • N & S Hemisphere have opposite seasons due to the tilt of the Earth's axis
    • S Hemisphere tilted toward sun: summer (this is winter in the N hemisphere. 
  • As Earth orbits around the Sun, different areas receive direct or indirect sunlight due to the tilt of Earth on its axis. This is what causes seasons.
  • Earth’s distance away from the Sun does not cause the seasons.
  • 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 EarthFor 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.
  • Characteristics of the Moon: 
    • 239,000 miles from Earth
    • Moon is about 1/4 the size of Earth
    • Composition is similar to Earth
    • Has iron core, mantle, crust
    • Covered in dormant volcanoes & craters which are the results of impacts from  and  over billions of years.
    • Why is it covered in craters? 
      • It does not have an atmosphere to protect it from the impact of objects such as asteroids in space.
      • There is no wind on the Moon to  existing craters.
    • Climate: The Moon has no atmosphere, wind, or weather. Thus, the temperature can range from extremely hot to extremely cold since there is no atmosphere to protect it from the Sun’s heat or insulate the surface.
    • Gravity: Remember, more mass=more gravity and less mass=less gravity. As such, the Moon has 1/6 of the gravity of Earth. This means if you weigh 60 lbs on Earth, you would weigh 10 lbs on the Moon.
  • Sides of the moon: 
    • Two sides
    • The near side (the side we can see from Earth) 
    • The far side (the dark side) 
    • Gets light from the sun 
    • Since Earth has a larger mass, it exerts a stronger gravitational pull on the Moon.
  • Tidal locking: Since Earth has a larger mass, it exerts a stronger gravitational pull on the Moon. Earth’s pull controls the Moon’s orbit so that the Moon rotates once on its axis in the same amount of time it takes to orbit Earth. Therefore, the same side of the Moon is always facing Earth and we have a near side and a dark side. 

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