This looked very impressive to me ....
I had ordered a MacBookAIR laptop on the Internet and it felt like
it was only one or two days ago when I found the box containing
the laptop sitting on my porch.
Even more impressive:
the FedEx printout showed that FedEx had picked it up at 11:35 a.m. on March 27,
and delivered it here in Pennsylvania at 10:18 a.m. on March 28 - less than 24 hours later !!!
Except that .... once again I forgot about the IDL (International Date Line)!
In fact, when the parcel left from Shanghai, China
(located at the edge of the Asiatic Continent or Tectonic Plate)
on Thursday March 27 at 12:15 p.m. on its way across the Pacific,
it just required 18 minutes to cross the entire Pacific
(the World's largest) Ocean c.q. Tectonic Plate - to arrive in Anchorage, Alaska
on the North American Continent/Plate -
still on Thursday March 27 at 12:33 a.m. WOW!
Unbelievable, unless you belief that packages can be tele-ported
or sent by radio-waves, laser beam, or whatever.
Just for kicks, let's see how long it would take if it traveled by tsunami?
The tsunami's speed would be the square root of gd,
[where g, the acceleration due to gravity, is about (10 meter per second)2
and d, the depth of the ocean, about 4 kilometer,] which equals (=) 200 meter/second,
while the distance from Shanghai to Alaska is some 7,000 kilometers.
(more exactly, 6,934 km in a straight line)
yielding as answer 35,000 seconds or 9.72! hours
(where the ! is a time saving device to avoid having to write down an infinite number of 2's fo which I
do not have time right now)
Wrong, however, because:
(1) although a tsunami is a progressive, shallow water wave,
one cannot put the laptop box on top of the wave
since it is said to be the wave form that moves at that speed,
not the water (and laptop) itself
(2) a tsunami is infinitely more likely to travel from Alaska to Shanghai than the other way
Back to the I.D.L., International Date Line.
Let's assume the box traveled from Shanghai to one millimeter before the IDL
and reached there at 22:30 local time on Thursday, March 27.
Going on another millimeter it is now suddenly 22:30 local time on Wednesday March 26 !!! which will
allow it (on its airplane, traveling at about the same order of magnitude in speed as the tsunami) another full
24 hours just to catch up and achieve the - previously - seemingly impossible to arrive in Anchorage
by 12:33 a.m. on
(the next day) Thursday March 27.
I recall my excitement when I learned about time zones in physics in Grammarschool.
Every 15 degrees longitude corresponded to a time zone (because the earth rotates 360 degrees in 24 hours)
If you travel due east it gets later, if you go west, earlier. WOW!
In the middle of the night I suddenly woke up and combined my limited knowledge of relativity,
time, longitudes and latitudes and came up with this unrefutable (?) brainstorm/invention:
If one goes to the North Pole (instantaneously) and at that very spot stands on his/her toes
and spins around, and then travel back (instantaneously), one would arrive as many days before
or after one's departure as the number of rotations performed !!!
So this was time travel, unadulterated!
Imagine my disappointment in the next Physics class when the teacher acquainted us with the
concept (reality) of the International Date Line -
no more time travel for me, it was all spoiled -
leaving only the irritation for someone keeping a journal to either miss out
on an entire day, or having to record the same day twice -
especially when the diary you use has one pre-ordained page per day! ....
Of course, I might have thought it through a bit more thoroughly (oxymoron?),
but in that respect I goofed as much as Jules Verne's hero , Tobias Fogg
who traveled around the World in Eighty Days -
for he, too, forgot about the International Date Line!!
By the way, I once referred a naive female student to the IDL when she expressed an interest
in dating one or more foreign students. Sort out yourself how to interpret that, and as additional
challenge or assignment, also sort out which way to spin around at the North Pole to travel back in time,
anti-clockwise or cum-sole? hints: