Throwback
This person discovered the moons of Jupiter and the phases of Venus
Who is Galileo Galilei?
This element is the most common in the Universe
What is hydrogen?
Apollo 11 landed in one of these dark regions
What are Mare?
This person described the laws of motion and the theory of gravity
Who is Isaac Newton?
Where stars form
What are giant molecular clouds?
Our Moon is the outcome of this traumatic event
What is the giant impact with Thea?
This model had Earth at the center of the universe
What is geocentric model?
The three categories of worldbuilding materials, in order of decreasing density
What are rocks, ices, and gases?
This person calculated the first known estimate of the circumference of Earth using shadow lengths
Who is Eratosthenes?
The property of Earth's outer core that prevents S-waves from propagating
What is being liquid?
The planets of the Solar System formed out of this dusty structure 4.5 billion years ago
What is a protoplanetary disk?
This is the real reason Pluto isn't deemed a planet
What is not clearing its orbit?