"This'll make a swell home for people who like cold weather." Jak tried to change the subject.
"Yes, just as Two will for those who like it hotter." Jon's eyes shone. "Pop sure picked a winner when he decided to explore this system. Even with just these two worlds he has a prize."
"If they accept our work as proof. Wonder what the fourth planet will be like?" Jak continued in a different tone.
"Cold. Lots colder, probably, than Mars."
"Then it won't do us any good?"
"Depends on what's on it in the way of metals that can be mined. Maybe we'll find something there. Might be natural gems or jewels, too."
"And anyway, cold never stopped man."
"That's right," Jon said admiringly. "They have mines on Pluto, even—although they're mostly worked by automatics while the men stay warm in their bubble-cities."
As the Star Rover approached closer to the distant, smaller planet they had named "Jon," their instruments showed it to have a diameter of about 4400 miles, and a density of about 4.6, a little lighter than Terra. This meant the gravity would be a bit weaker, and they would weigh less than on their home planet. Four was almost a quarter of a billion miles from the sun, and would be very cold, as Jon had said.
While their ship drove in closer, the boys' mother came into the control room. All three Carvers stared excitedly into their visiplates, watching their rapid approach to this new world. Would they find anything of value there, or was it simply a barren wasteland of ice and frozen air and rocks, far too cold and forbidding for men even to bother trying to explore it?