"I don't know. We don't know how to do it, but it may be that our scientific progress wouldn't keep abreast of each other. We might know more than our minus counterparts in some fields, and they might know more in others. But their special knowledge enabled them to bridge the gap briefly—long enough to see us, and watch us—"
"And read our books." Red nodded.
"And perhaps learn our language—remember you got slapped."
"I'll watch it," said Red.
"There's no reason why the gap couldn't be bridged. Science and minds have done a lot of things that looked impossible."
We went to bed on that and all night long I dreamed of negative universes, with suns like old Sol except that they shone black in bright heavens and planets of space floating in vacuums of matter. Red must have dreamed about it too, because he had a question over the dehydrated ham and eggs the next morning.
"Does that explain the loss in mass for this asteroid?"
"I think it does. Either the method our minus counterparts have in bridging the gap, or perhaps some sort of space warp that permits them to do it. At any rate enough of the minus world has been projected through to our side of the equation to displace the mass of this planetoid. Our lab scales being haywire might be the result of a being's nearness to it, or something."
Red didn't digest it all, but I could see he was thinking. "I wonder what all this has to do with my whiskers," he mused.
We were busy making some further checks on the planetoid's mass later in the day when Red got a glimpse of the vision I'd seen. Red didn't take it quietly. He yelled loud and pointed.