There’s a lot more to Earth than meets the eye. Far from being just a roundish rock barreling through space, our planet is composed of several layers held together by intense forces of gravity.
Our planet’s interior is much too deep and hot to explore with probes, so scientists rely on seismic waves to understand and model its structure. Seismic waves are shock waves that propagate through Earth’s layers after an earthquake or explosive event, traveling at different speeds depending on the density and state of the material. The time it takes for these shock waves to bounce back up to Earth’s surface reveals aspects of the composition and physical properties of the rocks beneath.
Geologists today have a good understanding of Earth’s interior, based on pioneering work by Isaac Newton and Danish seismologist Inge Lehmann in the late 17th century and early-to-mid 20th century, respectively.
But how good is your knowledge of Earth’s inner structure? Find out by taking this quiz. If you need a hint, hit the yellow button. Good luck!
—Equator quiz: Can you name the 13 countries that sit on Earth’s central line?
—Antarctica quiz: Test your knowledge on Earth’s frozen continent
—Moon quiz: What do you know about our nearest celestial neighbor?
—Evolution quiz: Can you naturally select the correct answers?
—Conspiracy theory quiz: Test your knowledge of unfounded beliefs, from flat Earth to lizard people
