Cosmic Models and Thinkers
This early historical model placed a stationary Earth at the center of the entire universe.
What is the Geocentric Model?
This is the correct order of the first four inner planets, starting closest to the Sun.
What are Mercury, Venus, Earth, and Mars?
All four terrestrial planets share this specific physical surface feature, meaning a spacecraft could land on them.
What is a solid, rocky surface?
This invisible force holds millions or billions of stars, gas, and dust together inside a galaxy.
What is gravity?
This scientific discipline is defined as the study of stars, planets, moons, and the physical universe as a whole.
What is astronomy?
This Polish astronomer challenged ancient beliefs by mathematically outlining a Sun-centered model of the solar system.
Who is Nicolaus Copernicus?
This ring of space debris separates the four inner rocky planets from the four outer gas giants.
What is the Asteroid Belt?
Out of the four terrestrial planets, this one is the largest in size and volume.
What is Earth?
Galaxies that rotate with a central hub and curving outer arms resemble this rotating toy.
What is a pinwheel (Spiral Galaxy)?
Put these four cosmic structures in order from smallest to largest: Universe, Earth, Milky Way Galaxy, Solar System.
What is Earth - Solar System - Milky Way Galaxy - Universe
German mathematician Johannes Kepler improved the heliocentric model by proving planetary orbits are not perfect circles, but this oval shape.
What is an ellipse (or elliptical)?
Compared to the inner rocky planets, which are spaced close together, the four outer gas giants are spaced this way relative to one another.
What is much farther apart?
Out of the four terrestrial planets, this tiny, heavily cratered body is the smallest.
What is Mercury?
These smooth, featureless galaxies resemble 3D egg shapes or ovals and contain mostly older stars.
What are Elliptical Galaxies?
This term describes a simplified representation of a complex natural system used by scientists to make predictions.
What is a scientific model?
In 1610, Galileo Galilei used this tool to observe these the moons of Jupiter and the phases of Venus, proving that not everything orbits Earth.
What is the telescope?
Starting from the Sun, this planet sits as the 8th and farthest official planet in our solar system.
What is Neptune?
This specific atmospheric characteristic makes Earth unique among the terrestrial planets and allows life to survive.
What is an oxygen-rich atmosphere (and liquid water)?
Galaxies with no clear, symmetrical shape—often distorted by gravitational collisions with larger neighbors—belong to this category.
What are Irregular Galaxies?
This all-encompassing concept includes all of space, time, matter, energy, galaxies, stars, and planets that exist anywhere.
What is the Universe?
This ancient Greek thinker developed an early geocentric system based on five fundamental elements seeking their "natural place."
Who is Aristotle?
This general trend describes what happens to a planet's surface temperature as its distance from the Sun increases.
What is getting colder (receiving less solar energy)?
Despite being farther from the Sun than Mercury, Venus is the hottest planet in the solar system due to this atmospheric process.
What is a runaway greenhouse effect (trapping heat with thick carbon dioxide and sulfuric acid)?
This is the specific name given to our home galaxy.
What is the Milky Way Galaxy?
Because distances in deep space are too vast to measure in miles or kilometers, astronomers use this unit—defined as the distance light travels in one Earth year.
What is a light-year?