Page 141, Thought questions and problems 1. Over time the plate tectonic theory had to survive scientific tests. As we learned more about the Earth's interior and more bits of the fossil record were discovered it was found that the plate tectonic theory was consistent with all the new data. Identical land animal fossils on several continents implied that these continents were once closer together which implies that the continents move. The discovery of the mid ocean rifts showed that new material is flowing up towards the surface while the discovery of the subduction zones shows where the material sinks below.
Astronomers are still uncertain about how the Earth's atmosphere formed.
The problem with our current models is that there is not enough data to allow us to determine which of the popular models are best. A model may come to be accepted if new data supports it, while at the same time contradicting other models. Collecting area is the area over which a telescope focuses and collects light from a particular object. Generally this is the size of the opening of the telescope. The greater the collecting area, the more photons per second the telescope can collect from the area of interest.