Contents

23 July 2021
Vol 373, Issue 6553

About The Cover

Cover image expansion

COVER Vital clues to a planet's geologic history are contained in its interior. For 2 years on Mars, the InSight lander has recorded seismic data to constrain the planet's interior structure. The data reveal a layered crust, a mantle with a thick lithosphere, and a liquid iron-nickel core enriched in light elements, suggesting that Mars formed and evolved differently from Earth. See pages 388, 434, 438, and 443.
Illustration: C. Bickel/Science; Data: InSight Mars SEIS Data Service (2019)