Why is space three-dimensional?

Phys.org ^ | 3 May, 2016 | Lisa Zyga

[MtnClimber]

The question of why space is three-dimensional (3D) and not some other number of dimensions has puzzled philosophers and scientists since ancient Greece. Space-time overall is four-dimensional, or (3 + 1)-dimensional, where time is the fourth dimension. It's well-known that the time dimension is related to the second law of thermodynamics: time has one direction (forward) because entropy (a measure of disorder) never decreases in a closed system such as the universe.

In a new paper published in EPL, researchers have proposed that the second law of thermodynamics may also explain why space is 3D.

"A number of researchers in the fields of science and philosophy have addressed the problem of the (3+1)-dimensional nature of space-time by justifying the suitable choice of its dimensionality in order to maintain life, stability and complexity," coauthor Julian Gonzalez-Ayala, at the National Polytechnic Institute in Mexico and the University of Salamanca in Spain, told Phys.org.

..... The scientists propose that space is 3D because of a thermodynamic quantity called the Helmholtz free energy density. In a universe filled with radiation, this density can be thought of as a kind of pressure on all of space, which depends on the universe's temperature and its number of spatial dimensions.

Here the researchers showed that, as the universe began cooling from the moment after the big bang, the Helmholtz density reached its first maximum value at a very high temperature corresponding to when the universe was just a fraction of a second old, and when the number of spatial dimensions was approximately three. The key idea is that 3D space was "frozen in" at this point when the Helmholtz density reached its first maximum value, prohibiting 3D space from transitioning to other dimensions.

[Larry Lucido]

Not bad looking but kind of skinny.

Ann Coulter was going to be my other example.

[Califreak]

Ally McBeal

[disndat]

A third eye? Front or back? I always thought having an eye in the back of my head would be good. But knowing me I would always be wondering if I was coming or going.

[mountainlion]

Some say since some of the changing constants in this universe imply that we are a smaller part of a larger existence. Other branches say we may have 20 dimensions. We are little ignorant ameba with grandiose ideas of ourselves.

[kanawa]

Has no choice

[disndat]

I ain’t into skinny. I am from the land of corn fed women.

[DannyTN]

I can see where 2 dimensions could have it’s “draw”-backs.

But 6 dimensions could be interesting. The lingerie alone could be fascinating.

[MHGinTN]

If a point is real, space is four variable, not three.

[Just mythoughts]

Four dimensions, actually, including time. In any case, we are completely unable to perceive other dimensions, even if they did exist. With everything in the physical world describable in terms of the x, y, and z axes and time, what possible use is there for another dimension?

God created the flesh body, housing the soul/spirit intellect that is weighted by gravity cannot physically see other dimensions. Well, unless there is a purpose for any to be shown. But to say 'we are completely unable to perceive other dimensions,' is questioned by the Gospel. Christ was visible in His transfigured body, and yet in that body He went through a physical wall.

[Popman]

God seemingly has designed a lot of things using the number 3 (prime number)

Elements that make up the planet: Earth, wind, water...
Father, Son, Holy Spirit...
H2O...three molecules...
CO2....Three molecules...
Liquid, solid, vapor...

Just to name a few...

[disndat]

Right. So 2 dimensional. Must be why we have 3.

[tinyowl]

"And where would we be without ice cubes???"

When global warming melts the ice cubes, there will only be 2 dimensions because water is flat. Then the water will turn to steam and then shows over buddy, no more dimensions, no more polar bears because that's what polar bears eat and so on until the earth falls out of sky and splats on the ground like a bad egg.

[thoughtomator]

The Big Bang is a hypothesis that doesn’t hold up well to scrutiny, leaving everything that relies on it as a foundation in the realm of fantasy. The fudge factors involved would have long ago rendered any other hypothesis (save global warming) a laughingstock.

[smokingfrog]

The Universe is a Phi-based Dodecahedron

[disndat]

I thought polar bears ate latitudes because it is likes 90 degrees at the at the North Pole? Polar bears can’t survive long at 90 degrees.

[tinyowl]

I am such an idiot. You are totally right. I was thinking about the western poles. Don’t even listen to me. I’m a bad person, deep down inside.

[JoeProBono]

[lafroste]

There are 5 dimensions. (I’m serious)

[taxcontrol]

I would argue that time is not a dimension but a vector that can only be traveled in one direction.

[Reeses]

We only perceive three of them.

And our eyes only perceive three base colors. It's pretty hard to even imagine a new primary color. But computers have no problem imagining multi-dimensional objects and new colors. Maybe a computer generated virtual reality 5D world with dozens of base colors could be fed into a developing brain so someone could explore that kind of world and report back.