Starquake.pdf

"With a decent-size crustquake every three or four turns at the poles, at least he will have some data to
analyze." Time-Circle sounded dejected. "But why bother predicting crustquakes? Except for a few
accidents when a high-speed glide-car hits the ground during a big quake, the only thing a crustquake
does is crack a few compound walls or underground utility mains. At least we don't have the problem of
a 'roof’ overhead the way the humans do."
"You sound just like the grant committee. Always wanting to know, 'What good is it?' " She drew the
edges of her tread back. "What good is a new hatchling?"
"I'm sorry," he said. "I'm just feeling pessimistic about everything."
'Tell me about it," she said, drawing closer.
"In the beginning the project was fun," he began, "I had two bright graduate students. One doing the
experiments and one working on the theory. We sent messages back and forth in small increments of
time—just a few turns at first. Then we set up a series of progressively larger jumps until we were
sending short messages over a whole great of turns. We could code the messages in such a way that the
essential data was certain to get through, while the remainder of the message contained codes that
allowed us to determine the number of bits the channel was able to pass. We showed that the number of
bits the channel could handle was inversely proportional to the distance in time the message was sent.
Except for slight statistical variations, the bit-time product was always 864 bit-greats."
"So you could send a yes-no answer over 864 greats of turns," she said.
"Or 124,416 bits over one turn," said Time-Circle, his tread'trumming out the familiar train of numbers.
"Then, as the climax to both of their doctoral projects, we simultaneously sent messages on the three
forward-time channels to times two, three, and four greats into the future. The fourth channel we always
keep clear in case an urgent message needs to be sent."
Four greats is a long time to wait before you can finish your thesis," she said.
"We didn't have to wait at all," said Time-Circle. "Somewhere there was a minor calibration error
between the forward-time channels and the back-time channels.Before we sent out the test signals, we
received a response back from the future saying that all the signals had been received and giving the
number of bits that had made it through each channel. They all agreed with the theoretical prediction of
864 bit-greats."
"But suppose you had then decidednot to send the test messages into the future?" she asked.
"One of the students suggested that," he replied. "But I had already trod their edges on that subject early
in the project. Until we have a theory for these machines so we can understand the implications of
creating a paradox, we can't afford to take a chance.My guess is that every major paradox causes a
bifurcation of the universe. But it would take a good theory to suggest an experiment that wouldprove
that bifurcation had taken place."
"And you have a good theory?" she asked.
"Until a few turns ago, I thought I did," he said dejectedly. "Now, I'm not so certain."
"What happened?"