Seth Borenstein

Astronaut Gene Cernan traced his only child’s initials in the dust of the lunar surface. Then he climbed into the lunar module for the ride home, becoming the last person to walk on the moon. It was a moment that defined the Apollo 17 commander in both the public eye and his own. “Those steps up that ladder, they were tough to make,” Cernan recalled in a 2007 oral history. “I didn’t want to go up. I wanted to stay a while.” His family said his devotion to lunar exploration never waned, even in the final year of his...

WASHINGTON — In James Cameron’s fantasy films, like “Avatar” and “The Abyss,” the unexplored is splashed in color and fraught with alien danger. But on his dive to the deepest place on Earth, reality proved far different: white, barren and bland. Yet otherworldly — and amazing. “I felt like I literally, in the space of one day, had gone to another planet and come back,” Cameron said Monday after returning from the cold, dark place in the western Pacific Ocean, seven miles below the surface. “It was a very surreal day.” Cameron is the first person to explore the...