Geocentric vs Heliocentric

D) THE SOLAR SYSTEM HAS DEVELOPED
OVER TIME.

6.2 student will investigate and understand that the solar system is
organized and the various bodies in the solar system interact

Poll

How are you feeling today?

6.2D LEARNING TARGETS

I can evaluate changes in the understanding of the solar system over time as changes in technology
provided us more information.

I

6.2D KNOWLEDGE

Technological advances, breakthroughs in interpretation, and new
observations continuously refine our understanding of the Earth
and solar system

6.2 D KEY VOCABULARY

Earth-centered

robotic space craft

powerful Earth-
based telescopes
space telescopes
computer analyses
of huge data sets

TECHNOLOGICAL
ADVANCES

The invention of the telescope
provided powerful and confounding
observations that rapidly challenged
the Earth-centered model.

The development of mathematical
physics provided a scientific
explanation for the motion of the
nearby planets.

Multiple Choice

What invention changed the way people view the universe?

• space shuttle

• telescope

• satellites

• International Space Station

Multiple Choice

What did Scientists use to explain the movement of the planets?

• math and physics

• astronomy

• telescopes

• aliens

EARLY GREEK ASTRONOMER

Aristotle (384 – 322 BCE)

He believed the universe is a perfect sphere
with Earth in the center: Earth-Centered
(geocentric).

He also believed that objects in space also move
in perfect circles.

Multiple Choice

What is the geocentric model?

• Earth-Centered Universe

• Sun-Centered Universe

CHALLENGING ESTABLISHED IDEAS

Ptolomy (140AD)

Believed that Earth was the center of the
universe Earth-Centered (geocentric theory).

Noticed that Aristotle’s model did not explain
planetary movements.

Planets and stars move in Epicycles. In other
words, planets move in perfect circles within
circles.

This theory was used for almost 1600 years

Multiple Choice

Like Aristotle, Ptolemy believed in a geocentric model, but he added on-

• Sun centered model

• the movement of planets

• asteroids

REVOLUTIONARY IDEAS: CHALLENGING
ESTABLISHED IDEAS

Copernicus (1473 – 1543) A Polish Astronomer

Beginning of the Sun-Centered theory

Earth is not the center of “everything”

All the planets revolve around the Sun! (heliocentric
theory)

Still used “perfect” circles for the orbits

He waited until his own death before he published new
ideas.

On March 5th, 1616, Copernicus’ work was banned
from being taught and discussed by the Congregation
of Index “until corrected.” It stayed this list of
prohibited books and teachings until 1822!

Multiple Choice

Copernicus believed in a heliocentric model which is-

• Earth centered model

• Sun centered model

THE TELESCOPE

Galileo Galilei ( late 1500’s - early 1600’s)

First to point refracting TELESOPE towards the sky.

He studied the movements and orbits of many nearby planets
in our solar system.

Offered proof of Copernicus’s Sun centered model of our
Universe.

This led to the discovery of the moons of Jupiter.

Multiple Choice

What invention did Galileo use to prove Copernicus Sun centered model?

• microscope

• telescope

• math and physics

FROM CIRCULAR ORBITS
TO ELLIPTICAL ORBITS

Johannes Kepler early 1600’s

Used math to calculate that planets
moved in orbits and along ellipses.

Multiple Choice

Until Kepler, it was believed that the planets moved in perfect circles. He proved that they moved in ellipses using -

• telescope

• math

• a ruler and compass

TODAY! THE SUN IS CENTER OF UNIVERSE AND
PLANETS MOVE IN ELLIPTICAL ORBITS AROUND IT