The conversation between human and AI assistant.
Who discovered plate tectonics and how?
How did Harry Hess come up with the idea of seafloor spreading?
Harry Hess proposed the idea of seafloor spreading based on his observations of the mid-Atlantic Ridge. He noticed that the rocks on either side of the ridge were different ages, with younger rocks closer to the ridge and older rocks further away. He suggested that this was because new crust was forming at the ridge and spreading outwards, carrying the older rocks away from the ridge.