Models and Theories
Long ago people thought Earth was at the center of everything.
What is the geocentric model?
Our solar system is inside this galaxy.
What is the Milky Way?
Mercury, Venus, Earth, and Mars are called these because they have rocky surfaces.
What are the inner (rocky) planets?
The force that pulls objects together and toward larger masses.
What is gravity?
Made of ice and dust; these often grow tails when they get close to the Sun.
This model says the Sun is at the center of our solar system.
What is the heliocentric model?
The Milky Way is just one of billions of these huge collections of stars.
What are galaxies?
Jupiter, Saturn, Uranus, and Neptune are called these because they are large and made of gas or ice.
What are the outer planets?
The tendency of an object to keep moving unless something stops it.
What is inertia?
Rocky objects mostly found in the belt between Mars and Jupiter.
What are asteroids?
The theory that the universe began from one tiny, hot point and has been expanding.
What is the Big Bang Theory?
Put these in order from smallest to largest: planet, star, solar system, galaxy.
What is planet → star → solar system → galaxy?
The largest planet in our solar system.
What is Jupiter?
Two words: the two things that work together to keep planets in orbit.
What is gravity and inertia?
A small rock in space (smaller than an asteroid).
What is a meteoroid?
This Italian scientist used a telescope to study the skies and gave evidence that supported Copernicus’ heliocentric model.
Who is Galileo?
The name for everything that exists — all matter, energy, galaxies, and space.
What is the universe?
The only planet we know of that supports life.
What is Earth?
If gravity suddenly disappeared, planets would travel in this kind of path instead of curved orbits.
What is a straight line?
When a meteoroid burns up in Earth's atmosphere and looks like a "shooting star."
What is a meteor?
This Polish scientist first suggested that the Sun, not Earth, was at the center of the solar system.
Who is Copernicus?
Compared to a galaxy, the Sun is this.
What is much smaller?
This inner planet is known as the "Red Planet."
What is Mars?
Which two factors determine how strong gravity is between two objects?
What are mass and distance?
When a space rock survives and lands on Earth, it is called this.
What is a meteorite?