All of Chapter 7 Flashcards
What shape is our solar system’s orbit?
Elliptical
How many stars does our solar system contain?
100-400 billion stars
What is an astronomical unit (AU)
The average distance between the sun and the earth
What is our nearest star named? How far away is it?
Proxima Centari, 4.3 light years away
What is a light year?
The distance light travels in a year
What is the Nebular Hypothesis?
The theory that the solar system was developed from a primeval nebula
What is Geocentric?
The idea that earth is the center of the universe
Who had a working model with the EARTH as the center of the solar system?
Ptolemy (Ideas commonly accepted for 1500 years)
Why did Ptolemy’s idea’s survive?
The theory fit the observations of the day
What is Heliocentric?
The idea that the sun is the center of our solar system
Who was first to propose the SUN centered model?
Copernicus
What was Galileo’s 2 greatest contributions?
1) The improved telescope
2) The new observation/evidence that the earth is not the center of the universe
Who was Kepler and what was his contribution to the idea of our solar system?
He was a mathematician that correctly described how planets move around the sun
What were the 3 laws Kepler discovered?
1) Planets do not move in perfect circles
2) When an object is closer to the sun it moves faster
3) Third law is used to determine distance planets are away from the sun.
What are 2 reasons why the ideas of our solar system changed?
1) Technology improved
2) Better observations led to better understanding