it could do ... they would
require energy enough to break down the cohesive forces of molecules.
There isn't any way we know of to harness that kind of energy and
channel it in a hand weapon. Nobody on Earth...."

He broke off and stared at them.

"That's right," Johnny said. "Nobody on Earth."

"You mean ... extraterrestrial?"

"There isn't any other answer," Johnny said. "_Look_ at the thing,
Major. _Feel_ it. Does it feel like it was made for a human hand? It
doesn't fit, it doesn't balance, you have to hold it with both hands to
aim it...."

"_But where did it come from?_" the Major said. "We've never had
visitors from another star system ... not in the course of recorded
history. And we know that Earthmen are the only intelligent creatures in
our Solar System."

"You mean that they're the only ones _now_," Tom said.

"Or any other time."

"We don't know that, for sure," Tom said.

"Look, we've explored Venus, Mars, all the major satellites. If there
had ever been intelligence on any of them, we'd have known it."

"Maybe there was a planet that Earthmen haven't explored," Tom said.
"Even Dad tried to tell us that. The quotation from Kepler that he
scribbled down in his log ... 'Between Jupiter and Mars I will put a
planet.' Why would Dad have written that? Unless he had suddenly
discovered proof that there _had_ been a planet there?"

"You mean this ... this gun," the Major said.

"And whatever else he found."

"But there's never been any proof of that theory ... not even a hint of
proof."

"Maybe Dad found proof. There are hundreds of thousands of asteroid
fragments out there in the Belt, and only a few hundred of them have
ever been examined by men."

On the desk the strange weapon stared up at them. Evidence, mute
evidence, and yet its very existence said more than a thousand words. It
was there. It could not be denied.

And someone ... or _something_ ... had made it.

Slowly the Major pulled himself to his feet. "It must have happened
after his last message to me," he said. "It wasn't part of the scheme we
had set up, but he made a strike just the same ... an archeological
strike ... and this gun was part of it." He picked up the weapon, turned
it over in his hand. "But it was days after that last message before his
signal went off, and the Patrol ship moved in."

"It makes sense," Johnny Coombs said. "He found the gun, and something
more."

"Like what?"

"I wouldn't even guess," Joh