The Big Bang Theory, Geocentric, and

Heliocentric Models of the Solar System

The Big Bang Theory

We often think of this…

In Science, though, this is what we mean…

The Big Bang Theory (Write)

What does this theory tell us?1. What occurred at the beginning of the

universe – about 14 billion years ago.2. Everything was packed into a small, dense

singularity. 3. Eventually, the singularity exploded sending

space and time in all directions.4. After explosion, the universe was very hot.

When it cooled, galaxies and stars began to form.

5. Universe is expanding.

The Big Bang Theory Comparison (Don’t Write – Just Listen)

Raisin Bread

Before placing the dough in the oven, the raisins are very close

together. After adding heat, however, the raisins spread farther

and farther away from each other. According to the Big Bang

Theory, the same thing happened in the universe. It was like

the dough, very compact, and then exploded (adding heat) and

expanded.

Space Exploration (Write)

• In the beginning, people made observations of the Sun, Moon, and the first five planets with their naked eyes.

Turn and talk…

At night, when you look at the sky, what do you see? During the daytime, when you look at the sky, what do you see? Do you think we would know all we know about space if we still only used our eyes?

Geocentric Model of the Solar System (Write)

The Ancient Greeks (Ptolemy) tried to explain what they saw in the sky. Because they saw the Sun, stars, and Moon moving through the sky, they believed they were revolving, or orbiting, the Earth. This was the Geocentric Model of the Solar System.

Geocentric Model of the Solar System (Write)

• Let’s break this thing down…– The prefix “geo-”

means Earth.

– “centric” means centered.

– So, geocentric means earth-centered.

Heliocentric Model of the Solar System (Write)

In the early 1500s, the Polish astronomer Copernicus proposed the heliocentric view of the solar system.

Heliocentric Model of the Solar System (Write)

With more careful observations and the invention of the telescope, people began to understand that the heliocentric model of the Solar System was accurate.

Heliocentric Model of the Solar System (Write)

• Let’s break this thing down…– The prefix “helio-”

means Sun.

– “centric” means centered.

– So, heliocentric means sun-centered.

Did you know…?? (Don’t write, just listen)

• In the 1630s, Galileo (an Italian scientist) published a book that included both the geocentric and heliocentric views. Because the book favored the heliocentric view, Galileo was sentenced to permanent house arrest.

Turn and talk, Part II

How do you think we could relate what we’ve learned about the scientific method to the discoveries made by Copernicus and other astronomers?