Question

In the late 1600s, English astronomer Edmond Halley presented a model of Earth’s structure. Halley originally claimed that Earth was composed of an outer rocky shell and an inner rocky sphere, separated by a wide gap filled with glowing air. He thought that Earth had two sets of magnetic poles: one permanent set that originated on the surface, and another set that originated in the inner sphere. Halley believed that the inner set of magnetic poles moved over time because the inner sphere rotated slightly slower than the outer shell. He also thought that the inner sphere was just as habitable as the surface.

Halley knew that his model was hypothetical and might not be completely correct, but he thought that it could explain some important observations, calculations, and inferences about Earth’s properties. His model was based on information and evidence available at the time, but it was also based on some nonscientific beliefs that many people at the time accepted. The idea that Earth is hollow was not new—many people thought that there were vast caverns that extended deep into Earth’s interior.

Suppose that you know very little about Earth’s interior and want to find out how accurate Halley’s model is. How would you go about evaluating the validity of the model? What sort of evidence would you need to collect and how could you collect it?

a) Which scientist proposed the model of Earth's structure in the late 1600s?
b) What were the main components of Edmond Halley's Earth model?
c) What were Halley's beliefs regarding the inner set of magnetic poles and their movement?
d) Why did Halley acknowledge that his model might not be completely correct?

Answer 1

Halley's model of Earth's structure in the late 1600s proposed an outer rocky shell, inner rocky sphere, and glowing air in between. He believed in two sets of magnetic poles that moved due to the rotation of the inner sphere. His model was based on scientific knowledge and nonscientific beliefs.

Step-by-step explanation:

Halley's model of Earth's structure in the late 1600s proposed that Earth was composed of an outer rocky shell and an inner rocky sphere, separated by a wide gap filled with glowing air. He believed that Earth had two sets of magnetic poles: one permanent set on the surface and another set in the inner sphere. Halley thought that the inner set of magnetic poles moved over time because the inner sphere rotated slightly slower than the outer shell. He acknowledged that his model might not be completely correct because it was based on both scientific knowledge and nonscientific beliefs of the time.