"I don't care about the details. Just try to give me a simplified version of the principle."
Professor Duchard gazed into the younger man's eyes. Caught the fierce light within them—the gleam of spirit that marks those who will not be downed for long, no matter what the odds. The ray of struggle that only death could take away.
For a long moment, then, the old man sat buried in thought. At last he looked up again. Broke the silence.
"Have you ever seen the physical experiment in which a wave of sound is used to break a glass?"
"No. But I've heard of it. I know what you're talking about."
"Very well, then. Imagine, if you can, that the barrier between space and time is that glass. It is apparently impenetrable."
"I see." Elaine's fiance nodded eagerly.
"Then try to conceive of a terrific wave of energy being concentrated against it, just as the sound wave is concentrated on the glass. But this time, the wave must be so manipulated as to strike the barrier as a pebble strikes and breaks a window. Otherwise it would be too weak to break through. Or, if it was strong enough, it would break down the entire space-time relationship."
Again Mark nodded, this time more slowly.