Instead, let me break it down for you like a true casual science communicator would do.

So what is this “Ricci” thing anyway? Well, it’s basically a way to describe how space and time are curved in our universe (or any other spacetime). And when we talk about curvature, we usually think of things like circles or spheres but in general relativity, the curvature is much more complicated.

To understand this better, let’s take a look at an example. Imagine you’re standing on a curved surface (like a sphere), and you want to measure how “curvy” it is. One way to do this would be to draw a line segment between two points on the surface, and then calculate the angle between that line and a straight line connecting those same two points in flat space. The smaller the angle, the more curved the surface is at that point.

Now let’s apply this idea to general relativity. Instead of measuring angles between lines, we measure something called “Ricci curvature” which tells us how much spacetime curves around a given point or direction. And just like with circles and spheres, the more curved spacetime is in one place, the less it’s curved somewhere else (because all that extra curviness has to go somewhere).

So what does this have to do with Ricci decomposition? Well, as it turns out, there are actually two different ways to measure Ricci curvature and they give us very different insights into how spacetime behaves. The first way is called “Ricci scalar” (or just plain old “scalar”), which tells us the overall amount of curviness in a given region of space. And the second way is called “Ricci tensor”, which gives us more detailed information about where and how that curviness is distributed.

Now, you might be wondering why do we need both scalar and tensor? Can’t we just use one or the other? Well, as it turns out, there are actually some situations where using only one of these measures can lead to problems (like when spacetime has “negative curvature” in certain places). But by combining them into a single decomposition called “Ricci decomposition”, we can get a much more complete picture of how spacetime behaves and that’s what makes it such an important tool for understanding the universe.