Tag Archives: 2D space

Flat Space of the Torus

Flat Earth!

To describe how space could be flat, finite, and yet unbounded, science writers sometimes use an analogy involving the surface of a torus (the mathematical abstraction of the doughnut shape). Such a surface has no boundary — no edge.  And despite being embedded in three-dimensional space, the torus surface, if seen in terms of compensating surface metric, is indeed flat.

Yet a natural issue people have is that the three-dimensional embedding is clearly curved, not flat. It’s easy to see how wrapping a flat 2D sheet into a cylinder doesn’t distort it, but hard to see why wrapping a cylinder around a torus doesn’t stretch the outside and compress the inside.

In fact it does, but there are ways to eat our cake (doughnut).

Continue reading


Expanding the Middle

My blog has such low engagement that it’s hard to tell, but I get the sense the last three posts about configuration space were only slightly more interesting than my baseball posts (which, apparently, are one of the least interesting things I do here (tough; I love baseball; gotta talk about it sometimes)).

So I’m thinking: fair enough; rather than go on about it at length, wrap it up. It’ll be enough to use as a reference when I mention configuration space in the future. (There have been blog posts where I couldn’t use the metaphor due to not having a decent reference for it. Now the idea is out there for use.)

And, at the least, I should record where the whole idea started.

Continue reading


SF or Fantasy, Pick One?

It’s Science Fiction Saturday, so today I want to consider a fairly common question a fan might encounter: “Science Fiction or Fantasy?” The implication is that one tends to exclude the other. In these polarized times, it can amount to a declaration of your tribe.

One problem is there’s a spectrum from hard SF to pure fantasy with everything in between. But let’s take them as two legitimate poles and consider the question in terms of configuration space. (See posts #1 and #2 if you need to catch up.)

I think you’ll see that using a space give us a new take on the question.

Continue reading