Origins of the universe

Everything orbits around the earth. What is this theory called?

Everything orbits around the sun. What is this theory called.

Why is gravity greater on the earth than on the moon? Answer with number.
1. Because of the size difference
2. Because moon is closer to the sun
3. Because Earth contain more substances that cause gravity

What is the very beginning of the universe called?

What happened a few seconds after the moment of singularity

When did the Big Bang happen?

What kind of elements started to form shortly after the moment of singularity? Answer with number.
1. complex
2. small
3. simple

What era did lights start to form?

When did radiation era begin in the Big Bang? Answer in the form shown: "-----years later"

When did first stars start to form? Answer in the form shown: "----- years later". Also, what is this era called? Separate answers with ("/ "). Add space after slash.

Who proved that the space was increasing its size?

Non-contact force of attraction between objects

what evidence suggests that Big Bang actually happened?

what is cosmology?

who was the first person to propose the geocentric model of the solar system?

who was the first person to discover the heliocentric model?

famous prussian mathematician who agreed with the heliocentric model

who proved that planets' orbits were elliptical

How did Galileo prove the heliocentric model? and when?

Newton

who made the big pendulum