How do people know whats inside the earth?
Geophysicists study things like earthquakes and how the waves pass through the earth. The waves will usually travel faster in denser rocks, and some waves will not travel through liquids—therefore the interpretation that the outer core is liquid, because some EQ waves do not travel there. We can also measure things like changes in the earth’s gravitational attraction, the amount of heat that flows out of the earth, and various electrical properties of the rocks—even though they may be very deeply buried. Then scientists put all this information together and try to make some sense out of it. Sometimes it works, but sometimes we just get more questions.
