"We couldn't get an answer?"

"Very unlikely. Besides, I am having the cube refitted for a
two-months' cruise. Rather thought I'd like to visit Mars and
Jupiter in person.

"But when it comes to leaving the solar system entirely the
telepathic method is the only one that will work; even the nearest
of the fixed stars is out of the question."

"How far is that?" Smith inquired.

"The nearest? About four and a half light-years."

"Yes, but what's a light-year?"

"It amounts to sixty-three thousand times the distance from here to
the sun!"

Smith whistled. "Nothing doing in the cube, that's sure. Besides,
could we expect to find any people like us in the neighborhood of
that star?"

"Not Alpha Centauri." The doctor reached for one of the Venusian
books, and pointed out certain pages. "It seems that the Class IIa
stars--that is, suns--are the only ones which have planets in the
right condition for the development of humans. The astronomers
already suspected as much, by the way. But the Venusians have
definitely named a few systems whose evolution has reached points