Question

Lesson 4: Theories about the Universe
Word Bank-you may use a word more than once.

Element

same

sun

Geocentric

Andromeda

telescope

math

gravity

out

radiation

older

single

Heliocentric

How is the universe organized? There are many theories. The **Geocentric** Model states the Earth is at the center of the universe. This was one of the **older** theories and made sense to people because people did not feel like they were on a moving object and they saw objects (sun, stars, moon) move across the sky. In this theory all objects move at the same speed. A blank with the geographic model was the observation that objects were in blank locations in the sky on different days.

Answer 1

In the **Geocentric** Model, there was a notable observation that objects appeared in **same** locations in the sky on different days, but their positions slightly changed due to their movements. This led to the realization that the Earth is not the only object in the universe.

In contrast, the **Heliocentric** Model proposed by Copernicus suggested that the **sun** is at the center, with planets, including Earth, orbiting around it. This model explained observations more accurately, such as the retrograde motion of planets, which the **Geocentric** Model struggled to account for. The **telescope** was a crucial tool that helped to support the **Heliocentric** theory, revealing more about the positions and motions of celestial bodies.

Additionally, advancements in **math** allowed astronomers to calculate the gravitational influences of these bodies, leading to our understanding of **gravity** and how it governs the movements of planets in the cosmos.

The discovery of galaxies like **Andromeda** shows that there is not just a **single** universe, but many, each with their own elements and structures, further expanding our understanding of the cosmic scale and the **radiation** emitted by distant stars and galaxies.

In revisiting these models, it's clear that while the **Geocentric** Model was foundational, the **Heliocentric** Model provided a more accurate representation of how the universe is organized and its vastness.