Les
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Lecture 3 covers how dark matter makes its appearance from observation of orbital velocities of matter in a galaxy which should be faster near the center and slower further out. Instead most orbital velocities are about the same. The answer is that some spherical volume of matter much larger than the center must be taken into account. The Bullet Galaxy example was brought up. I was converted.
I got through lecture 4, which is pretty tough in some parts. But it had a lot of interesting stuff. In particular the difficult part had to do with the work done by pressure in 3-d on some container, and how energy density changes with the size of the container, then deriving the vacuum energy. Susskin uses a box. I was familiar with most of this from using gas welding tanks. It is amazing how much physics and chemistry you absorb by learning to weld.
Anybody interested in this stuff should get to lecture 4. A lot of things are pulled together. I am afraid I was also converted to the dark energy.
Part of what makes DM and DE interesting to me, is they say, we don't know half of what we should.
Meanwhile astronomy, which Susskin calls gas-tronomy is getting closer and closer to the period of early post recombination, and finds fully grown galaxies with supernova in the early matter dominated universe, close to 350,000yrs.
Well, and there is the great positive nature of this kind of learning. I am not learning about how rot-shit the US political world is, how rot-shit the environment is so we'll all drowned while the US government does its best to keep profits high and dry for the one percent, in the water world of dystopian tomorrow.
One does get tired of all that.
CG