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27 Cards in this Set
- Front
- Back
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What are the two main motions of Earth?
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Rotation and Revolution
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What is Rotation?
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Rotation is the turning, or spinning, of a body on its axis.
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What is Revolution?
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Revolution is the motion of a body, such as a planet or moon, along its orbit around some point in space. (Earth revolves around the Sun)
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What is Precession?
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Precession is the slight movement, over a period of 26,000 years of Earth's axis.
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What are the results of Rotation?
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The main results of rotation are day and night.
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What did Nicolas Copernicus do?
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He proposed that the sun was at the center of the solar system and we orbited in circles around it.
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What did Aristarcus do?
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He was the first to say we revolved around the Sun. He did this by looking at the shadow of the earth on the moon during an eclipse of the moon.
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What did Johannes Kelper do?
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He was an assistant to Brache and continued his work. He discovered that the orbit of planets are not circles but ellipses. (Discovered the 3 laws)
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What did Galileo Galilei do?
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He made the first telescope. His observations supported Copernicus's idea of a sun-centered universe. He discovered 4 moons that orbit Jupiter. This proved that Earth wasn't the center of motion in the universe. He discovered planets are circular disks. He discovered that Venus goes through phases like the moon. Discovered the moon's surface was not smooth. He discovered that the sun had sunspots, and it rotated in just under a month.
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What did Issac Newton do?
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He was the first to test the law of universal gravitation.
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The law of Universal Gravitation
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This law states that the more mass an object has, the more gravitational pull it can exert.
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Heliocentric Model
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In this model, the Earth and the other planets orbit the sun.
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Geocentric Model
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The Earth remains motionless in the center, while the other planets go around it.
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Retrograde Motion
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The illusion that planets would move east, then stop, then reverse direction, and then resume its path eastward.
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Who was Ptolemy?
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Ptolemy was the first to explain retrograde motion. He explained retrograde motion by saying the planets moved along smaller circles which in turn moved along their orbits around the Earth. These smaller circles are called epicycles.
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Astronomical Unit (AU)
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The average distance between the Earth and the sun. It is about 150 kilometers.
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What causes the phases of the moon? and how long does it take?
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The phases of the moon as to do with how much of the sunlit side of the moon is facing Earth. On a synodic month it takes 29.5 days,and on a sidereal month it takes 27.3.
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What is a solar eclipse?
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A total solar eclipse occurs when the moon moves in a line directly between Earth and the sun. (We are in the moon's umbra) It casts a dark shadow on Earth.
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What is a lunar eclipse?
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A total lunar eclipse occurs when the moon moves within Earth's shadow or Umbra. During a total lunar eclipse, the moon appears to be blood red. This is because Earth's atmosphere bends and transmits some long wavelength light (red) into its shadow.
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Maria
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A dark relatively smooth surface. It is the ancient beds of basaltic lava, originated when asteroids punctured the lunar surface, letting magma bleed out.
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Highlands
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Densely pitted light colored mountain ranges.
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Regolith
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Soil like layer. Composed of igneous rocks, glass beads, and fine lunar dust. 3 meters think.
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Formation of the moon
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The most widely accepted model for the origin of the moon is that when the solar system was forming, a body the size of Mars impacted Earth. This would have sent debris everywhere and some never left Earth's orbit (the Moon)
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Apogee
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When the moon is farthest from Earth.
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Perigee
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When the moon is closest to the Earth.
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Aphelion
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When any planet is farthest from the sun.
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Perihelion
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When any planet is farthest from the sun.
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