I still remember seeing this for the first time when I was a kid. Though it's still hard for me to fully grasp the concept of what higher dimensions would look like, this demo really blew my mind.

I never viewed the world the same way after watching "Cosmos". It was a life-altering series to me.

Tags for this video have been changed from 'carl, sagan, explanation, 4th, fourth, dimension, tesseract' to 'carl, sagan, explanation, 4th, fourth, dimension, tesseract, cosmos' - edited by kronosposeidon

^Exact same experience. I remember rewinding the 4th dimension part over and over and just not being able to understand it. I just randomly bumped into at youtube and it still blows my mind.

This is a high-quality dupe of:

http://www.videosift.com/video/Carl-Sagans-Cosmos-Tesseract

Sorry.

I once attempted to explain an aspect of quantum theory by showing that higher dimensions we can't see can hide interactions that we only see the results of. It sounded plausible to me, but mathematician friends laughed at me. I brought up flatland and they patiently explained that it's a teaching tool, not a "real" representation, and you can only truly see it numerically. If you try to apply physics using your imagined flatland, you get some serious issues. Something to keep in mind, and yet another reason to get serious about math!

'Theories such as string theory and M-theory predict that physical space in general has in fact 10 and 11 dimensions, respectively. The extra dimensions are spacelike. We perceive only three spatial dimensions, and no physical experiments have confirmed the reality of additional dimensions. A possible explanation that has been suggested is that space is as it were "curled up" in the extra dimensions on a very small, subatomic scale, possibly at the quark/string level of scale or below.'
wiki

for instance the big bang had to have happened in another form of time or causality means it would never have happened. our universe has to exist in some framework, with gravity, time and our own few dimensions working the way that they do.

*kill

Permanently discarding this video - kill requested by submitter dystopianfuturetoday.