🚀 go-pugleaf

http://www.people.fas.harvard.edu/~djmorin/book.html
Introduction to Classical Mechanics
David Morin
Cambridge University Press
Chapter 11, p. 14: "Twin A stays on the earth, while twin B flies
quickly to a distant star and back. Show that B is younger than A when
they meet up again. Solution: From A's point of view, B's clock is
running slow by a factor gamma, on both the outward and return parts
of the trip. Therefore, B is younger than A when they meet up again.
This is the answer, and that's that. So if getting the right answer is
all we care about, then we can pack up and go home. But our reasoning
leaves one large point unaddressed. The "paradox" part of this
example's title comes from the following alternate reasoning. Someone
might say that in B's frame, A's clock is running slow by a factor
gamma, and so A is younger than B when they meet up again. It's
definitely true that when the two twins are standing next to each
other (that is, when they are in the same frame), we can't have both B
younger than A, and A younger than B. So what is wrong with the
reasoning at the end of the previous paragraph? The error lies in the
fact that there is no "one frame" that B is in. The inertial frame for
the outward trip is different from the inertial frame for the return
trip. The derivation of our time-dilation result applies only to one
inertial frame. Said in a different way, B accelerates when she turns
around, and our time-dilation result holds only from the point of view
of an inertial observer. (...) For the entire outward and return parts
of the trip, B does observe A's clock running slow, but enough
strangeness occurs during the turning-around period to make A end up
older. Note, however, that a discussion of acceleration is not
required to quantitatively understand the paradox, as Problem 11.2
shows."

The moment a rational scientist comes to find the following excerpt
consistent he becomes irrational, that is, he becomes a Believer:

"For the entire outward and return parts of the trip, B does observe
A's clock running slow, but enough strangeness occurs during the
turning-around period to make A end up older. Note, however, that a
discussion of acceleration is not required to quantitatively
understand the paradox, as Problem 11.2 shows."

http://www.haverford.edu/physics/songs/divine.htm
No-one's as dee-vine as Albert Einstein
Not Maxwell, Curie, or Bohr!
He explained the photo-electric effect,
And launched quantum physics with his intellect!
His fame went glo-bell, he won the Nobel --
He should have been given four!
No-one's as dee-vine as Albert Einstein,
Professor with brains galore!
No-one could outshine Professor Einstein --
Egad, could that guy derive!
He gave us special relativity,
That's always made him a hero to me!
Brownian motion, my true devotion,
He mastered back in aught-five!
No-one's as dee-vine as Albert Einstein,
Professor in overdrive!

http://www.youtube.com/watch?v=5PkLLXhONvQ
We all believe in relativity, relativity, relativity.
Yes we all believe in relativity, 8.033, relativity.
Einstein's postulates imply
That planes are shorter when they fly.
Their clocks are slowed by time dilation
And look warped from aberration.
We all believe in relativity, relativity, relativity.
Yes we all believe in relativity, 8.033, relativity.

Pentcho Valev
pvalev@yahoo.com