"I tell you again," swore Gary, "that camera did not move! The action you see depicted on those prints is but one of two things: either the motion of the comet, itself, or—" He breathed deeply, then plunged—"or the effect worked upon the comet's light-rays by its presence in our galaxy!"
Dr. Anjers glanced at him with swift concern. "What is that? Our galaxy! I am afraid you have been overworking, my young friend—"
"Just a moment, Doctor! I have further proof." The younger man's hands dug into his portfolio. "Dr. Bryant, let me ask you a question. If you were asked to declare the most baffling of all astronomical puzzles, what would you select?"
"Why—why, I suppose the 'red shift', Gary."
"Exactly! From the early Nineteenth Century to this day, one riddle which has amazed and confounded scientists is the apparent movement of our universe. According to all evidence, our universe is composed of a multitude of galaxies—each of which is running away from all others at unbelievable speed.
"This we know because of the 'red shift'—which one might call the 'Doppler effect' applied to light, rather than to sound. When one star, comet or galaxy approaches another, pressing its light waves upon its neighbor, the cosmic body's light waves are shortened. They shift toward the violet side of the spectrum.
"Similarly, a receding luminary pulls its waves—and the pitch of its light is indicated by a 'red shift.'
"Observation has taught us the tragic falsehood that everything in the universe is running away from all else. We have learned to believe in an 'expanding universe'.
"But—" Once again Gary placed his finger upon the photographs—"study these margins! These fine lines are the spectrographs of the comet you have just seen. Do they agree with our established theories?"