Duality

Yours truly is fascinated by mirrors but you, my loyal readers, already know that as reflections garnered from such objects, whether they be natural or artificial, reveal subtle qualities of the reality they reflect, something physics takes very seriously when trying to discover the true nature of reality from the subatomic to the multiverse.

When you look in the mirror, the image you see looks a lot like you—not exactly the same, because when you raise your right hand, your mirror-self raises its left. What’s more, the mirror image is merely an assemblage of reflected light, without a physical body behind it. Despite these differences, you can see an important connection between you and your reflection.

This type of mirror relation is a familiar and powerful form of symmetry. We can say that a Valentine heart is symmetrical because the left side is a reflection of the right. But the symmetry of your mirror image is different and deeper. A heart is symmetrical because the left and right side happen to have a similar shape. The symmetry between you and your reflection is due to the laws of physics. The nature of light requires your reflection to be symmetrical to you. It is an example of a powerful and subtle type of symmetry known as duality.

It gets better.

Perhaps the most powerful duality in physics is known as the holographic principle. This principle is often misrepresented as the idea that the universe is actually a hologram, but it is more accurate to say there is a duality between a volume of space and the surface enclosing that volume. The holographic principle states that all the information contained within a region of space can be determined by the information on the surface containing it. Mathematically, this means the volume of space can be represented as a hologram of the surface, hence the idea’s name.

This idea is less crazy than it sounds at first. Imagine a hotel with a guard at the entrance. Since everyone entering or leaving the hotel must pass the guard, he can count the number of people entering or leaving to know how many people are in the hotel. Thus information gathered by the guard (at the surface) tells us about the number within (the volume). (This example is obviously much simpler than considering all of the information in a three-dimensional space, but it illustrates how this information could be imprinted on the surface.)

Read the Nautilus piece in it's entirety, worth the time to learn a lot, I know I did.

Curiosity, when properly applied, never kills the cat. - Robert E. :)