Science Unit 3 Test- Units 1 and 2

What is the solar system?
It is the sun and all of the planets and other bodies that orbit the sun.
Who purposed the early models of the solar system?
Aristotle, Aristarchus, Ptolemy, Copernicus, Kepler, and Galileo.
What is the heliocentric model?
The earth and other planets that orbit the sun.
What is geocentric model?
The idea that the earth was the center of the solar system.
What is the parallax?
The apparent shift in the position of an object when viewed from different locations.
Who first observed the phases of Venus?
Galileo.
Who attempted to measure the relevant distance from the moon and to the sun?
Aristarchus.
Who replaced circles with ellipses in a heliocentric model of the universe?
Ptolemy.
Whose geocentric model of the solar system was accepted for 1,400 years?
Ptolemy.
Whose heliocentric model is seen as the first step in the development of modern models of the solar system?
Copernicus.
What are Kepler’s laws?
First law- planetary orbits are ellipses with the sun at one focus
Second law- planets move faster in their orbits when closer to the sun
Third law- relates the distance of a planet from the sun to the time it takes to go once around its orbit.
What is gravity?
Force of attraction between an object that is due to the masses and the distance between them.
What is an orbit?
A path that a body follows as it travels around another body in space.
What is aphelion?
When an object is farther away from the sun.
What is prehelion?
When the object is closest to the sun.
What is centripetal force?
The path that a body follows as it travels around another body in space.
What is the solar nebula?
A cloud of dust and gas that formed the solar system.
What are planetesimals?
Small bodies that formed the planets.
What are terrestrial planets?
The inner planets that are closer to the sun.
What are the gas giant planets?
The planets that were formed in the outer disk that have deep atmospheres of gas and ice.