Physics Discussion Continues
June, ’80
"All right already, enough," Jade said. "We need to start at the beginning.
Best I can remember it all began with Max Planck's black body radiation
experiments at the turn of the century. He discovered that radiation
or light propagates in discrete packets. Those packets are called the
quantum of action. The energy in a quantum of action varies, but its
discreteness doesn't. That discreteness is known as Planck's constant.
Particles in classical physics evolve in a continuous manner, and in
three dimensions of space, but in atomic physics that just doesn't
seem to be the case. With the discovery of the quantum of action,
there was a merging of the dynamic state of the elements under study
with their localization. The particles' independence dissolved, as it
became impossible to simultaneously determine position and momentum,
an impossibility for which the uncertainty relations of Heisenberg
became the precise expression. After the uncertainty principle,
Cartesian space and time co-ordinates ceased to be applicable, and
physicists were forced into learning new rules for a new game. In
fact, all the conjugate variables of analytical mechanics--energy,
time, momentum, position, had to be dealt with as approximations; they
had to be dealt with in terms of statistical analysis. Ultimately,
with the loss of space and time localization, physicists were forced
to abandon their concept of a deterministic physical universe."
"Oh yeah, and what about Einstein," Don said. "Did he abandon the
concept of determinism? What happened to his space and time?"
"Well, not exactly," Jade replied. "His space and time are still
there, only it's not just his space-time any longer, it's everybody's."
“I’ve always wanted to know about relativity. Fill me in why don’t
you,” Don said.
“I’d really like to except it’s all a little fuzzy for me, too,”
replied Jade. “I really don’t understand much about it. That’s a whole
different physics, one that doesn’t fit in well with quantum
mechanics. That was the problem that haunted Einstein his entire life.
He never stopped trying to solve it. And if he couldn’t do it, don’t
expect help from me. You’re right, though; Einstein never did give up
his belief in a deterministic universe. In his physics, determinism
was preserved, everything else fell apart.”
“So tell me about it,” Don said. “If a ball is still a ball and we can
calculate its velocity and position in Einstein’s universe, then what
do you mean; fall apart how?”
“Basically, relativity doesn’t come into significant play until
you’re working with velocities at close to the speed of light,” replied Jade.
“When those speeds are approached, compared to say, the speed of
a bullet, space and time measurements become radically different when
measured relative to each other. In Einstein’s Special Theory Of
Relativity the space and time measurements of the system under study
are tied to the frame of reference of the observer. A yardstick and a
clock traveling at close to the speed of light will measure thirty-six
inches and identify twelve o’clock to an observer in that reference
frame, but when the same yardstick and clock are measured against
other frames of reference, say like here on earth, earth clocks will
run slow and yardsticks will measure less than thirty-six inches. Sir
Isaac Newton’s absolute space and time collapsed under the weight of
Einstein.”
“Oh yeah, now I understand,” replied Don. “Bullets are small compared
to the sun, so their length is measured with a short yardstick while
sun spots are large compared to bullets, so they’re measured with long
yardsticks, right!”
“That’s not exactly what I said, Don. Measuring rods traveling at
close to the speed of light,” said Jade, “when compared to measuring
rods here on earth measure short, and the same goes for clocks, they
run slow. And, vice versa, when earth clocks are compared to clocks
traveling at close to the speed of light, then those clocks run slow.
I don’t know why. I’m not an Einstein. I guess it has something to do
with the constancy of the velocity of light, but other than that it’s
a mystery to me, just like it must be a mystery to you. Look, I can
see we’re not getting anywhere here, especially since I’ve already
admitted I don’t know much about Einstein’s theories. Let’s just say
that by using Einstein’s equations, a person can figure out how to
measure both the length and speed of an earth bullet and the length
and speed of a bullet traveling at close to the speed of light and
then communicate that knowledge to an alpha centurion provided that
the alien understands the equations. Once again, I don’t now how that
can be done, but I do know it has something to do with Einstein’s
General Theory of Relativity, which further develops the concept of
the space-time interval. A space-time interval, when measured relative
to different reference frames, does not vary, but don’t ask me to
explain that because I can’t.”
“Fair enough,” Don replied. “Don’t explain.”
“Now that I think of it, though,” said Jade, “I need to put a little
perspective on what I just said.”
“Do you really?”
“Have another drink, Don,” Jade replied.
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