Test 2 Flashcards
The time for one Earth rotation
Day
The time for one Earth orbit around the sun
Year
The approximate time for the moon to orbit Earth
Month
How could people of ancient times tell the time of the year?
They built ancient structures as a calendar to aid in farming and hunting
What two ways do planets move across the sky?
- Direct Motion
2. Retrograde Motion
What is Direct Motion?
Normal eastward movement
What is Retrograde Motion?
Occasional westward movement
What did Aristotle assert about the universe?
Asserted that the universe is governed by physical laws
How did Aristotle describe the model of the universe?
The Earth is at the center of the universe
What contributions did Copernicus add to astronomy?
- Developed a mathematical modal for a sun-centered solar system
- Proposed the retrograde motion was really a result of parallax
What is the apparent motion of a body due to motion of the observer
Parallax
What contributions to astronomy did Tycho Brahe make?
He made precise measurements of the positions of the planets
What did Kepler describe about planetary orbits?
The orbit of a planet about the sun is an ellipse
What are Kepler’s three laws?
- The orbit of a planet about the sun is an ellipse with the sun at one focus
- A line joining a planet and the sun sweeps out equal areas in equal intervals of time
- The closer the planet is to the sun in its orbit, the faster it moves. The further away, the slower it moves
What happens as the planets get closer to the sun during their orbits?
They move faster
What is the average distance of the earth from the sun?
Astronomical Unit
What was Galileo the first to use?
Telescope
What were Galileo’s discoveries?
The moons of Jupiter, the moon
What is speeding up?
Acceleration
What is the gravitational constant times the product of masses divided by the square of distance between the masses?
Force
What is the energy of motion?
Kinetic Energy
What is stored energy?
Potential Energy