it cropped up in the early part of the twentieth century and it has been with us ever since.

Even our modern approach to unified theory, something called string theory, evokes the

possibility of more dimensions than the three that we experience, right. So we all know

about left-right, back-forth and up-down, right. Those are the three dimensions that

are all around us. We all move through them freely in day to day life. These other dimensions

suggested by theoretical considerations. There is no experimental evidence for any of what

I’m about to tell you. But the theoretical considerations suggest that in addition to

left-right, back-forth and up-down there may be other spatial dimensions. It’s hard to

picture like where could they be? There doesn’t seem to be any room left and that’s really

the point. They are new places that our experience doesn’t allow us to access directly but

according to this theoretical ideas might be there.

I have a little analogy that helps to understand this. Think of a garden hose is one that we

love to use. So think about a garden hose that’s nice and long. Now from far away

the garden hose is going to look one dimensional because that’s the only part that you have

the visual acuity to see because the circular part is just too small for your feeble eyes

to detect. But then if you take a pair of binoculars from a faraway vantage point now

you see that there is a circular dimension, a circular part that wraps around the garden

hose that you missed when you just used your feeble senses. So dimensions can be big, obvious

and easy to see or they can be curled up and tiny, much more difficult to detect. Now the

garden hose is an object in our universe. But this idea might apply to space itself,

right. So it could be that left-right, back-forth and up-down are the big easy to see dimensions

like the horizontal extent of the garden hose. But just as the hose has a curled up dimension,

maybe space itself has curled up dimensions all around us, just curled up to such a fantastically

small size that we can’t see them with our eyes. We can’t see them even with today’s

most powerful microscopes. But the possibility according to the mathematics well motivated

by these attempts of realizing Einstein’s dream of unified theory, the math suggests

this as a real possibility that there may be more dimensions than the ones that we directly

experience.