I suspect it is also a play on Yahoo Serious who played Einstein in http://www.imdb.com/title/tt0096486/

This also has to do with the fact that Hawking, at one point, proposed that matter could be destroyed in a black hole. This runs contrary to the principle that Einstein was adamant about. He has since been dis-proven and has rescinded his this theory.

The actual meaning is that very few people live in Alaska. And a home school is a school where parents teach their children only. Therefore, being the governor of Alaska is comparable to being a principal over two or three students.

Also note how slowly these lines are delivered. The Cat, recognizing he can not rap faster than the Bard, instead opts to rap more slowly.

“Green Eggs and Ham,” a book written by Dr. Seuss, also heavily uses repetition in its characters' dialogue.

Or just a reference to the speed at which Shakespeare just delivered his 2nd round. Esspecially since he hasn’t yet referenced either Things

The gesture that Sarah Palin made in this line may also be a reference to one of Queen’s renowned songs, Radio Ga Ga.

This is a play on words on Lady Gaga’s stage name. Palin suggests that she may be “Gaga”, but she’s not a “Lady” (referencing, as above, her alleged transvestism). Also, just after she says “Gaga”, clapping is heard, referencing the Queen song “Radio Gaga”, where Lady Gaga took her stage name from.
http://www.youtube.com/watch?v=UiuD6i8dN1g

It’s also a joke on her name, ‘Lady Gaga’. Sarah says that her name is not true: she’s not lady Gaga, she’s just Gaga.

This is also an example of Hawking “stretching out the rhyme,” or rapping over the musical bar.

I find this very offensive. I will suck all of you up with my black hole that I created from the spare parts of my wheelchair.

Since Hawking says the word, “million” nine times, it would have made more sense for him to say the world “billion” nine times. That’s 10⁸¹ which is more accurate.

That’s 100000000000000000000000000000000000000000000000000000000000000000000000000000000000 particles, approximately.

10⁸³ particles to be more exact.

To surmise: One of the currently held estimates is 10⁸⁰ particles in the known universe, under a google number of particles

There are something like ten million million million million million million million million million million million million million million (1 with eighty zeroes after it) particles in the region of the universe that we can observe. Where did they all come from? The answer is that, in quantum theory, particles can be created out of energy in the form of particle/antiparticle pairs. But that just raises the question of where the energy came from. The answer is that the total energy of the universe is exactly zero. The matter in the universe is made out of positive energy. However, the matter is all attracting itself by gravity. Two pieces of matter that are close to each other have less energy than the same two pieces a long way apart, because you have to expend energy to separate them against the gravitational force that is pulling them together. Thus, in a sense, the gravitational field has negative energy. In the case of a universe that is approximately uniform in space, one can show that this negative gravitational energy exactly cancels the positive energy represented by the matter. So the total energy of the universe is zero.
— Stephen W. Hawking
A Brief History of Time: From the Big Bang to Black Holes (1988), 129.