12 July 2013
Vol 341, Issue 6142

About The Cover

Cover image expansion

COVER Rendering of the Voyager 1 spacecraft that left Earth in September 1977. Last summer, when it was 18.5 billion kilometers away and still embedded in the solar magnetic field, Voyager 1 entered an unexpected region, where it observed a sharp decrease of charged particles from the Sun and an abrupt increase in particles from interstellar space. See pages 144, 147, and 150. Image: NASA