The document discusses changing models of the solar system. Originally, the geocentric model held that Earth was at the center of the universe with all other celestial bodies orbiting it in perfect circles. Copernicus introduced the heliocentric model in 1543, placing the Sun at the center. Galileo later provided evidence supporting this, observing Jupiter's moons orbiting it rather than Earth. Modern understanding is that planets follow elliptical, not perfectly circular, orbits around the Sun.

1. P1TOPIC 1 -VISIBLE LIGHT ANDTHE SOLAR SYSTEM
Changing Ideas ofThe Solar System
CVHS GCSE POWERPOINT SHARE
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2. Geocentric Model
Ancient Greek astronomers believed that the earth was at
the centre of the universe.
They believed that everything (sun, moon, planets and
stars) all orbited the earth in perfect circles.
The geocentric model was accepted up until the 1500s.
Copernicus published a book in
1543, which introduced the
Heliocentric model of the universe.
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3. Heliocentric Geocentric
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4. Heliocentric Model
Earth and planets orbit around the sun in perfect circles
Copernicus’ ideas weren’t popular and he was condemned
by the church
Galileo had good evidence for this theory...
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5. Galileo’s Evidence
In 1610, Galileo observed Jupiter's moons (using a newly
inverted telescope)
He found that they had moved the ‘wrong way’ around
the Earth, and later he saw one go behind Jupiter, and
another one appear.
These obviously orbited Jupiter, not the Earth.
Therefore, not everything orbited the Earth.
This proved the geocentric model wrong!
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6. Questions
When was the Heliocentric model first introduced, and
by who? (2)
Describe the geocentric model of the universe (3)
Compare the differences of the Geocentric and
Heliocentric models of the universe (2)
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7. Modern Day
Planets orbit the sun.
Elliptical orbits, rather than perfectly circular.
Discovery of new planets, such as uranus, with the
technology advances in telescopes.
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8. Questions
What do we know about orbits in the modern day (2)
Explain how ideas about the solar system have changed
from the time of the ancient greeks up until the modern
day (6)
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