"That might be so," declared the Engineer. "It is a theory we have often pondered. But we have no way of knowing. We have so little knowledge…"

A little silence fell upon the room, a silence filled with awe. This talk of universes and super-universes. This dwarling of values. This relegating of the universe to a mere speck of dust in an even greater place!

"The universes, even as the galaxies, are very far apart," the Engineer went on. "So very far apart that the odds against two of them ever meeting are almost incomprehensibly great. Farther apart than the suns in the galaxies, farther apart, relatively, than the galaxies in the universe. But entirely possible that once in eternity two universes will meet."

He paused, a dramatic silence in his thought. "And that chance has come," he said. "We are about to collide with another universe."

They sat in stunned silence.

"Like two stars colliding," said Kingsley. "That's what formed our solar system."

"Yes," said the Engineer, "like two stars colliding. Like a star once collided with your Sun."

Kingsley jerked his head up.

"You know about that?" he asked.

"Yes, we know about that. It was long ago. Many million years ago."

"How do you know about this other universe?" asked Tommy. "How could you know?"

"Other beings in the other universe told us," said the Engineer. "Beings that know much more in many lines of research than we shall ever know. Beings we have been talking to for these many years."

"Then you knew for many years that the collision would take place," said Kingsley.

"Yes, we knew," said the Engineer. "And we tried hard, the two peoples; We of this universe and those of the other universe. We tried hard to stop it, but there seemed no way. And so at last we agreed to summon, each from his own universe, the best minds we could find. Hoping they perhaps could find a way… find a way where we had failed."

"But we aren't the best minds of the universe," said Gary. "We must be far down the scale. Our intelligence, comparatively, must be very low. We are just beginning. You know more than we can hope to know for centuries to come."

"That may be so," agreed the Engineer, "but you have something else. Or you may have something else. You may have a courage that we do not possess. You may have an imagination that we could not summon. Each people must have something to contribute. Remember, we had no art, we could not think up a painting; our minds are different. It is so very important that the two universes do not collide."

"What would happen," asked Kingsley, "if they did collide?"

"The laws of the five-dimensional inter-space," explained the Engineer, "are not the laws of our four-dimensional universe. Different results would occur under similar conditions. The two universes will not actually collide. They will be destroyed before they collide."

"Destroyed before they collide?" asked Kingsley.

"Yes," said the Engineer. "The two universes will "rub," come so close together that they will set up a friction, or a frictional stress, in the five-dimensional inter-space. Under the inter-space laws this friction would create new energy… raw energy… stuff that had never existed before. Each of the universes will absorb some of that energy, drink it up. The energy will rush into our universes in ever-increasing floods. Unloosed, uncontrollable energy. It will increase the mass energy in each universe, will give each a greater mass…"

Kingsley leaped to his feet, tipping over a coffee cup, staining the table cloth.

"Increase the mass!" he shouted. "But…"

Then he sat down again, sagged down, a strangely beaten man.

"Of course that would destroy us," he mumbled. "Presence of mass is the only cause for the bending of space. An empty universe would have no space curvature. In utter nothingness there would be no condition such as we call space. Totally devoid of mass, space would be entirely uncurved, would be a straight line and would have no real existence. The more mass there is, the tighter space is curved. The more mass there is, the less space there is for it to occupy."-

"Flood the universe with energy from inter-space," the Engineer agreed, "and space begins curving back, faster and faster, tighter and tighter, crowding the matter it does contain into smaller space. We would have a contracting rather than an expanding universe."

"Throw enough of that new energy into the universe," Kingsley rumbled excitedly, "and it would be more like an implosion than anything else. Space would rush together. All life would be destroyed, galaxies would be wiped out. Existent mass would be compacted into a tiny area. It might even be destroyed if the contraction was so fast that it crushed the galaxies in upon each other. At the best, the universe would have to start all over again."

"It would start over again," said the Engineer. "There would be enough new energy absorbed by the universe for just such an occurrence as you have foreseen. The entire universe would revert to original chaos."

"And me without my life insurance paid," said Herb. Gary snarled at him across the table.

Caroline leaned her elbows on the table and cupped her chin in her hands. "The problem," she said, "is to find out how to control that new energy if it does enter the universe."

"That is the problem," agreed the Engineer.

"Mister," said Gary, "if anyone can do it, this little lady can. She knows more about a lot of things than you do. I'll lay you a bet on that."

CHAPTER Eight

The suits were marvelous things, flexible and with scarcely any weight at all, not uncomfortable and awkward like an ordinary spacesuit.

Herb admired his before he fastened down the helmet. "You say these things will let us walk around on your planet just as if we were at home?" he asked the Engineer.

"We've tried to make it comfortable for you here," the Engineer replied. "We hope you find them satisfactory. You came so far to help and we are so glad to see you. We hope that you will like us. We have tried so hard."

Caroline looked toward the Engineer curiously. There was a queer, vague undertone to all his thought-messages, an inexplicable sense of pleading, of desire for praise from her or from Kingsley. She shook her head with a little impatient gesture, but still that deep, less-than-half-conscious feeling was there. It made no sense, she told herself. It was just imagination. The thought-messages were pure thought, there was nothing to interpret them, nothing to give them subtle shades of meaning… no facial expression, no change of tone.

But that pleading note!

It reminded her suddenly — with a little mounting lump in her throat — of her bird dog, a magnificent mahogany-and-white Chesapeake retriever, dead these thousand years. Somehow she felt again as she used to feel when the dog had looked up at her after placing a recovered bird at her feet.

He was gone now, gone with all the world she'd known. Her ideas and her memories were magnificent antiques, museum pieces, in this newer day. But she felt that if, somehow, that dog could have been granted eternal life, he'd be searching for her still… searching, waiting, hungering for the return that never came. And rising in queerly mixed ecstasies of gladness and shyness if she ever came back to him again.

Kingsley spoke and the rising feeling snapped.

"Gravity suits," said Kingsley, almost bursting with excitement. "But even more than that! Suits that will let a man move about comfortably under any sort of conditions. Under any pressure, any gravity, in any kind of atmosphere."

"With these," Gary suggested, "we would be able to explore Jupiter."

"Sure," said Tommy, "that would be easy. Except for one little thing. Find a fuel that will take you there and take you out again."