Stats about our universe (in 199 words – didn’t make sense to split):
- there are 200 billion stars in Milky Way;
- age of universe between now and Big Bang is about 100 billion dog years;
- universe was very smooth in the distant past;
- entropy is the number of ways we can rearrange the constituents of a system so that it looks the same macroscopically;
- entropy increases (2nd law of thermodynamics) because there are many more ways to be high entropy than to be low entropy;
- every difference between past and future is because of increased entropy: that we can remember past but not future;
- 380.000 years after Big Bang, hydrogen and helium nuclei captured electrons to form stable atoms;
- gravity started compacting helium and hydrogen clouds, and once temperatures exceeded 10 million degrees, protons started fusing -there was a huge release of energy – the first star was born;
- from about 200 million years after the Big Bang, stars started appearing through the universe.
- when large stars die, they create temperatures so high that protons start fusing into all sorts of combinations creating new types of atoms.
- Goldilocks’ conditions of life: right amount of energy, diverse chemical elements, liquids (water).
- 1 billion years ago, first multicellular organism appeared.