Science has come a long way, especially in the field of astronomy. What early civilizations could only speculate, mankind can now know for certain thanks to modern advancements. Science has given precise measurements of unimaginable distances, images of objects billions of kilometers away, and detailed information about planets and moons humans have never visited.
Astronomers use various methods to determine the composition and atmosphere of a planet. One method to determine the composition is sending probes or astronauts to the surface. Astronauts brought rocks from the moon, which were studied to determine that the moon's composition is similar to Earth's. A more recent mission to find information about extra-terrestrial bodies is the Cassini-Huygens