smprather wrote:miturian wrote:there's an error on there, right? the arrow in the x-axis should be pointing to the left.
Hello fellow 1-poster. Yep. I came here to point out the same thing. I was at first confused about why the hydrogen bomb was on the far left at 100e6K.
The short answer is "tradition".
The H-R diagram was originally absolute magnitude against spectral class, with spectral classes going O,B,A,F,G,K,M,L,T with decreasing temperature, so you get a downwards slope. And when the scale got refined to use temperature rather than spectral classes, it stayed the "wrong" way round.