Home › CAST — California Science Test › Science › Earth as a Planet › Scientists work out the layered structure of Ear…
Scientists work out the layered structure of Earth's interior mainly by measuring what?
ASeismic waves passing through it
BOcean currents flowing over it
CSunlight reflecting off it
DMagnetic storms above it
Answer & Solution
Correct answer: A. Seismic waves passing through it
1. No one can drill deep enough to see the inside of a planet directly.
2. Waves from earthquakes travel right through the interior and change speed in each material.
3. Recording those seismic waves at many stations builds a picture of the layers they crossed.
4. Nothing at the surface, such as ocean currents or sunlight, carries information from that depth.
_Source: OpenStax Astronomy (CC BY 4.0), section 8.1 The Global Perspective_
Related questions
The Tunguska body carried the punch of a 5-megaton bomb, yet dug no crater. What explains The greenhouse effect currently lifts Earth's surface temperature by about 23 degrees CelsCarbonate rocks would release about 70 bars of carbon dioxide if heated, against a presentThe Pacific plate slides past the North American plate at about 5 centimeters a year, and About 2 square kilometers of new ocean floor form every year. What does that rate imply?Earth's bulk density is about 5.5 grams per cubic centimeter while its surface rocks are nA worldwide sediment layer from 65 million years ago is rich in which rare metal?Earth was struck as often as the Moon, yet shows far fewer craters. What removed them?