Imagine for a moment that despite all the evidence, Earth actually is not rotating and orbiting the Sun. Which of these hypothetical observations (none of them are real) would be inconsistent with our Sun-centered view of the solar system?
A) We find that we are unable to measure any parallax for a distant galaxy.
B) We discover an Earth-sized planet orbiting the Sun beyond the orbit of Pluto.
C) We discover that the universe is actually contracting, not expanding.
D) We discover a small planet beyond Saturn that rises in the west and sets in the east each day.
Question 2
What is the common trait of all main-sequence stars?
A) They are all spectral type G.
B) They generate energy through hydrogen fusion in their core.
C) They all have approximately the same mass.
D) They are in the final stage of their lives.
The greenhouse effect: heat trapping by earth's atmosphere.
Schematic of the Earth–Moon system (without a consistent scale)
Tides on Earth
Hierarchy of scientific evidence
Earth’s Major Lithospheric Plates
Early Earth