From an online article:
When [Rod] Serling started the opening credit narration in 1959, he initially said that there were six dimensions, but to avoid backlash, they changed it to five. “There is a fifth dimension beyond that which is known to man. It is a dimension as vast as space and timeless as infinity. It is the middle ground between light and shadow, science and superstition, and it lies between the pit of man’s fears and the summit of his knowledge. This is the dimension of imagination. It is an area we call the Twilight Zone.”
Backlash over “six dimensions”?
Comics I Don't Understand 
I think they were bowing to pressure from fans of Mr. Mxyzptlk.
Or, because time was generally called the fourth dimension, there was concern that mobs of angry viewers with pitchforks and torches would storm the studios demanding to know what the fifth was. Marilyn McCoo was only 16 years old, and Billy Davis wouldn’t form the band for another 7 years, after all.
My first thought was the band, too . . . altho I couldn’t figure out how to tie that in for a facetious comment.
I googled (interesting how that’s now a common verb) ‘sixth dimension’ and all sorts of mathematical/scientific explanations came up, but nothing I could see that would cause a backlash, but then, I’m not a mathematician or a scientist, so what do I know about their mindset.
Divad at 2 seems to have a good explanation. The objection wouldn’t be to the six per se, but to saying there are five known.
For the experts: how many dimensions are now used in the worst “wrapped extra dimensional” geometries for string theory?
I remember 13 (including 2 time dimensions).
The Big Dimension lobby was very powerful in the 1950s and 1960s.
I heard a story about this. but the version i heard was one writer saying “what if we talk about an extra dimension as well as time, so instead of four or five there are six”. The other writer said “but there’s only three dimensions; four if you include time”. And the first writer said “No there’s four normal ones; times the fifth and we’ll make up a new spooky one”. They asked a third writer and he agreed with the first.
At least that’s what I read…..
FWIW the pilot episode seems to carry the original narration featuring a “sixth dimension”.
The linked article mentions no backlash, just that Mr. Serling had written the line as sixth without any real thought behind it. Only after discussion with a producer did he change it to the more familiar “fifth”.
https://thenightgallery.wordpress.com/2013/10/02/a-sixth-dimension/
Grawlix…. yeah, that’s the story I heard.
M-theory (the result of various string theories being combined) is 11 dimensions – 10 space and 1 time.
My theory is 11 known dimensions of space plus 1 known dimension of time, so 100 total.
My theory is 11 known dimensions of space plus 1 known dimension of time, so 100 total.
“My theory is 11 known dimensions of space plus 1 known dimension of time, so 100 total.”
There are 10 types of people who will understand that joke.
Wait…there aren’t an infinite number of dimensions?
BTW, I don’t believe in parallel universes, but I am pretty sure there are perpendicular ones.
That’s my story anyway…
:-P
Dimension schooling
As a teenager, I remember getting angry when 3D movies were all the rage. “ALL MOVIES ARE IN 3D! Length, width and time!” I shouted to an empty bench in the school’s cafeteria.
Length, width and *depth, not time. So you were lucky the bench was empty 😂