Moon, Tides Flashcards
Moon and phases
- The moon has phases, it revolves around the Earth in 29.5 days
• One half of the moon is always lit
• The moon’s rate of rotation equals its rate of revolution – 27.3 days
• A new moon occurs when the moon is between the earth and the sun
• A full moon occurs when the earth is between the sun and the moon
when the sun is on the right side waning will be on the bottom and waxing will be on top
when the sun is on the left side waxing will be on the bottom and waning will be on top
Eclipses
- A solar eclipse: moon is between the earth and the sun and it blocks out the sun
• A lunar eclipse: Earth is between the sun and the moon and the shadow hits the moon
• Eclipses don’t happen every month–> the moon’s orbit is tilted 5 degrees
• The earth’s orbit is extremely round, almost perfect, but it is slightly elliptical
Tides
Tides are caused by the moon’s gravitational pull on the earth
- also the sun’s but not as much
• takes 12 hours 25 minutes one high tide to next high tide or one low tide to next low tide
- AND it takes 6 hours 12 minutes to go one high to one low
• Tides are considered cyclic because they are predictable and occur in a pattern
• When the Earth, Moon, and Sun are in a line a spring tide occurs
- spring tides are most extreme tides
• When the Moon and Sun are working against each other we get a smaller range of tides
- smaller range of tides are neap tides
Eccentricity
• Eccentricity is a measure of how oval or elliptical the orbit is
- highest =1, oval like or like a line
- lowest=0, perfect circle
• The further apart the foci are, the more eccentric the ellipse becomes
• One of the foci is always labeled as the sun
• The closer and larger two objects are, the greater the force of gravity
• As a planet gets closer to the sun or a star, the faster it orbits
- perihelion ~January 3rd (earths fastest time)
- aphelion ~July 4 (earths slowest time)
• When an object is close to another object, it looks bigger
- the sun looks biggest in winter
