Cosmology 101

This Isaac Arthur video is titled "The Compendium of Doom, Part 1". It's really a basic intro to cosmology. The part 2 of the video is continued on a different YouTube channel as part of a collaboration. Part 2 covers the ways in which the Universe could end in the distant future.

Listening to the video made me realize just how little humanity really knew about the Universe before the 1800s. 100 years ago it still hadn't been established yet that other galaxies existed. I think it used to be referred to as the "island universe" hypothesis. I was thinking about how I could have proven Andromeda was a separate galaxy before Hubble's research but I don't think I could have.

Near the end of the video it was pointed out that the Cosmic Microwave Background radiation used to be infrared and will eventually in the far future be in the radio spectrum. That's really interesting to think about. Radio is as long of a wavelength as you can realistically get in the electromagnetic spectrum. The far future and presumably the majority of the Universe's entire lifetime will have RF as the cosmic background.

This report was published via Actifit app (Android | iOS). Check out the original version here on

Daily Activity, Walking