Humans love classifying things into different groups. Whether it is tiny single celled organisms or literal galaxies in space, humanity just wants to put each item into its own bucket to help understand it better.

Normally, this is a very useful way of learning about various things. In almost all cases, however, there are going to be outliers, that just don’t fit nicely into any category. For example, the platypus. Sure, it’s a mammal, but it lays eggs, but it also has a pouch, oh, and it is venomous. Yeah, it is just a weird outlier that doesn’t fit nicely into any group.

Well, the same thing sometimes happens with galaxies, and that is the case with galaxy NGC 2775.

Astronomers have set up four main categories of galaxy that has been observed.

First, there is the spiral galaxy, which is very common and happens to be the type of galaxy that our own Milky Way is. Spiral galaxies have ‘arms’ that stick out from a center that is more densely populated with stars. Most of the time, spiral galaxies also have lots of gas and dust, which means it is much more active when it comes to creating new stars.

Next up is the elliptical category, which is also quite common. Elliptical galaxies are usually older and larger than spirals. The stars are not distributed uniformly across a disk, but in a more spherical arrangement. Astronomers have found that this type of galaxy is often the result of two (or more) galaxies merging in the past.

The third is the lenticular galaxy, which is much rarer. This type has some characteristics of both spiral and elliptical galaxies. They often have a bulge in the center, and a disk extending out, but no spiral arms. These are normally very old galaxies and have very little new star formation. The stars are a lot older, on average.

Then there is the always fun ‘other’ category for anything that doesn’t fit in anywhere else. Astronomers don’t like to use this category because it is basically just giving up and saying they don’t know. That, however, is where NGC 2775 seems to fit.

The outer area of the galaxy looks like a spiral galaxy, with gas and dust sticking out in a disk. The central area, on the other hand, seems just like an elliptical galaxy. Due to the fact that we can only see it from one angle, astronomers can’t determine whether the distribution of stars is flat or spherical.

It could be that this is actually two galaxies in the process of combining. Or it is an older galaxy that has gone through an unusual lifecycle. Or it could be transitioning from a spiral galaxy into a lenticular one.

The bottom line is that astronomers just don’t know at this point, so for now at least, it will just have to sit in the ‘other’ category, frustrating researchers.

If you think that’s impressive, check out this story about a “goldmine” of lithium that was found in the U.S. that could completely change the EV battery game.