If you look out the windows at a busy airport, or maybe out the porthole on your next airplane ride, you might notice that many planes are mostly white but the ring at the forward tips of their engines is always silver. There’s a reason for that, and it’s not just style.

In this video, YouTuber breaks down an explanation for us. According to him, and he’s wearing a pilot’s uniform so he seems to know what he’s talking about, there a few reasons why this piece of a jet engine is left unpainted.

Mainly, it’s about heat. Or, really, heat as it applies to safety. Ice forming on the front of jet wings and their engines is a real risk when flying through cold clouds, so jets have the ability to redirect some hot air they’re already generating to this front ring to keep it hot and prevent ice from forming.

Anti-icing systems, as they’re called, are pretty cool and interesting in their own right. If you’re curious to dig into that, here’s a good video on that subject too:

If you don’t feel like watching, basically, the engine can bleed off some hot air to melt ice through little holes inside the wings and in that ring around the engine tip. Here’s a cutaway from aeronautical YouTuber Captain Joe:

Getting back to why that piece is unpainted, it’s simply that metal is a good heat conductor and paint would hinder that, making the anti-icing process less effective.

A secondary reason jet manufacturers don’t paint this piece is to prevent the unlikely but potentially catastrophic possibility of a paint chip flaking off and getting swallowed by the sensitive and expensive engine.

Finally, the aerodynamics of this engine tip piece is critical for efficiency, and painting it would just add one more layer of potential imperfections in the shape.

The Mentour Pilot clip also gets into why so many planes are white, and it’s exactly the same reason I prefer white trucks for desert driving. The air conditioning doesn’t have to work quite as hard because a white vehicle reflects more light than one painted a dark color.

There’s also a cost factor. It’s not cheap or quick to paint something as large as a commercial airliner, so doing a simple design with a mostly-white livery makes the decorating process easier and also makes it a little less of a pain for owners to change branding if a jet is sold from one airliner to another. Which is apparently not at all uncommon.

So now you know–and if anybody tries to sell you a dark-painted plane, maybe see if you can talk the price down. And definitely don’t paint over the metal tips of the jet engines and wings.