The year is 2117. The United World Science Foundation has sanctioned a team of geologists to explore the remote minor planet known as Sedna. About one-half the diameter of Pluto, Sedna orbits twice as faraway from Earth as Pluto is, and at this distance, it receives only weak sunlight and is dark, cold, and forbidding. Discovered in the first decade of the twenty first century, the first astronauts landed on its surface in 2087. This geological team will be the first scientists to explore the surface of this remote icy world. Astronomers have been unable to explain the unusual mass,...