From leading astronomy writer, Phil Plait, on the Wisconsin H-Alpha Mapper: One of my favorite things is to learn something new. Especially when it’s something big. In this case, I mean it literally: The galaxy is filled with warm, ionized hydrogen gas, it forms a huge pancake-like structure 75,000 light years across and more than 6000 light years thick, and it has a name: the Reynolds layer. Even better, when it was discovered, it was a shock, briefly defying explanation until better physical models of the galaxy made it more clear.
Office of Strategic Communication