September 15th, 2022

Big Bang to Humankind

  • The full moon in September is called the “Harvest Moon”, but it’s just a regular full moon (in September).
  • The moon closer to the horizon looks red because there’s more atmosphere you’re looking through, and red light isn’t as scattered by it.
  • Cosmic Microwave Background Radiation: microwave light in all directions that’s left over from the Big Bang.
    • Evidence for the Big Bang — the theory predicts this radiation, and they found it.
  • The data support not only an expanding universe, but also accelerated expansion of the universe.
  • The universe is expanding at a rate greater than the speed of light.
  • You would predict that the center of galaxies should rotate much faster than the edges. But that’s not what’s observed. So we explain that with dark matter — there’s 10x more mass than we can observe.
  • Galaxies are expanding from each other, but stars and planets aren’t (the scale is too small).
  • Galaxies start as discs because they collapse and then spin out.
    • Other shapes (like footballs) are formed from merging galaxies.