Discover the Hertzsprung-Russell diagram, a key tool graphing the brightness of stars against color in astronomy.

HR Diagram If you look at the HR-Diagram (attached to this post), you can see many dots. Each dot represents a star. The Universe has many stars in it; hence there are many dots on the diagram ...

This makes red giants at the TRGB point of the HR diagram something that astronomers call a " standard candle." Hubble trouble solved by stars that boil and bubble?

Stars come in different types, and most stars will change types throughout their lifetimes. Stars are often organized using what's known as the Hertzsprung-Russell (H-R) diagram.

First, astronomers place each star in the cluster on a Hertzsprung-Russell (HR) diagram, which plots a star’s brightness and color (which is related to temperature).

NGC 6397 contains more than 400,000 stars, which gives us a lot of points. Using the color and magnitude of each star, we can convert to temperature and luminosity and put them on the H-R diagram.

And now my friend Stuart who runs Astronomy Blog has done it one better: he’s created an H-R diagram of media stars. It’s awesome: That’s really funny, and I wish I had thought of it. The ...