# Could 2-D & 3-D & 4-D atoms interact?

• Lren Zvsm
Lren Zvsm
Most of us have probably read Edwin Abbot's "Flatland," which was published in 1884.

https://www.gutenberg.org/cache/epub/201/pg201.txt

In this novella, sapient and motile polygons & circles inhabit a two-dimensional world. Late in the story, a sapient sphere presents itself to the two-dimensional characters. As it passes through the plane, the 2-D characters see the sphere as the edge of a circle that appears out of nowhere, grows larger then smaller, and then disappears.

In modern terms, we have three-dimensional atoms interacting with two-dimensional atoms.

Sometimes I write about my own original superheroes for my own amusement. One of my characters has the power to take on the characteristics of a four-dimensional creature. Obviously, I could make a comic-book character any way I wanted to, given the prevalence of pseudoscience in the genre. (Arc-reactors, anyone?) But I would like to write this character with as little handwaving as possible.

So, my question should read "Is it possible for atoms that have different numbers of spatial dimensions to interact, assuming that spaces with different numbers of dimensions can intersect each other?

Also, when my character switches from 3-D to 4-D, what happens to his/her/its size?

I don't see why not. The narrator did it in Flatland.
He simply interacted as a cross-section through Flatland.

There was another story, whose provenance I forget, wherein a 4D creature did the same thing in our 3-dimensions. The hero stabbed the creature through the foot, pinning it to the ground so it couldn't leave the 3D dimension.

BTW, I stumbled across this list of reading material:
https://www.theguardian.com/books/2020/jun/03/top-10-four-dimensional-novels-mark-blacklock-hinton
Some are apt, some are not.I didn't actually read this article but just the blurb gave me idea of a Flatlander donning a "skinsuit" that would make his 2D body have a thin 3D dimension, allowing him to enter the 3D world without harm and interact as a 3D shape.

Lren Zvsm
Lren Zvsm said:
Also, when my character switches from 3-D to 4-D, what happens to his/her/its size?

If the character's atoms have the same diameter and properties in 4D and are somehow rearranged so that the character becomes 4D then the character's height is about three millimeters. Their surface area goes up by a factor of three hundred. (I have a thread about this in this subgroup.)

If the character's atoms are not rearranged then they flop to the ground while all their bodily fluids flow out into the new dimension.

Lren Zvsm
A lot of setting sci-fi rules comes down to what you want to do with your characters and story. Edwin Abbot wanted to talk mathematics, and sidestepped into some social commentary. As Hornbein suggests, dimensional interaction lends itself to body horror. I'm not into that, but some people are.

I can't imagine the addition of an extra dimension being anything but devastating to the lower one. Since they have zero in the missing dimension, their mass is zero relative to the higher dimensional object. Even on the atomic scale, that is going to be a mess. It's probably best to hand wave it all away, as Edwin Abbot does, and stick to what your story is about.

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Lren Zvsm and DaveC426913