Ideas about the solar system Flashcards
Who came up with the geocentric model?
Ptolemy, a Greek astronomer.
What did astronomers use measurements of the movements of objects in the sky for?
To explain how the Sun, Moon and planets moved in circles.
What does the geocentric model state?
The earth is at the centre of the universe and the sun, moon, planets and stars all orbit the earth in perfect circles.
How long was the geocentric model accepted for?
From the time of Ancient Greeks until the 1500’s.
Who introduced the heliocentric model?
Nicolaus Copernicus, a polish astronomer (1543)
What does the heliocentric model state?
That the sun is at the centre of the universe and the earth and all the planets orbit the sun.
When did the heliocentric model replace the geocentric model?
In the 1600’s.
How did Ptolemy make observations?
Using the naked eye.
How did Copernicus make observations?
Using a telescope.
Why did Copernicus question Ptolemy’s idea?
Copernicus thought that Ptolemy’s measurements fitted a different model - one with the sun at the centre of everything.
How did Gailileo’s observations provide evidence for Copernicus’ theory?
Gailileo was observing Jupiter using a telescope when he discovered three stars in a line near the planet.
- he then plotted their movements and found that they were moving in the wrong direction.
- a fourth star appeared and when he found that they never moved away from Jupiter and seemed to be carried with the planet he realised that these four objects were actually moons orbiting Jupiter, not stars.
- this showed that not everything was in orbit around the earth, proving the geocentric model to be wrong.
How was Gailileo able to make his observations?
He invented a telescope towards the end of the 16th century, which allowed him to see objects in space in much greater detail than with the naked eye - thus allowing him to find new objects.
How has the improvements of technology helped us?
Our idea of the solar system and universe has changed.
