So now we come to Week 8, the final week in our course. We'll start out as usual, with a quote of the week. And major topics this week, we'll build on some of the things we've been doing. First of all, traveling the galaxy, so this will come out of our analysis of the twin paradox last week. So we'll think a little bit more about that. Then talking about the famous equation, which of course is E=mc squared and how that fits in to things here a little bit. Traveling the galaxy part 2, once we know a little bit about the famous equation energy, we'll say a few more words about what we were doing here in terms of traveling the galaxy and how feasible it is, how much fuel we might need to actually get some place. Then we'll actually just spend a couple video lectures on the general theory of relativity, just introduce a few of the key concepts here. We can't go into the details. This course isn't about that, plus it requires a lot more math than we want to tackle. But we'll start with the happiest thought, what Einstein termed the happiest thought of his life, or the most fortunate thought of his life. So actually we'll find out what that happens to be. And then another consequence of this happiest thought actually is the bending of light and the gravitational field, so we'll look at that. And then end up with making a few final comments on some topics we've touched on here and there. But want to emphasize a few points such as the role of crucial experiments in science and in physics, such as the 1919 eclipse expedition that we'll talk more about. So the role of crucial experiments, the nature of genius, a few words on that, a few thoughts on that. Question of relativity versus relativism, what the difference between those is and how they are confused sometimes. And then end it off with a few comments on Is this all really real? When we talk about time dilation, length contractions, some of these weird results, the twin paradox, is it really real? And so that's where we're going this week. And we'll also, of course, have a weekly summary at the end and one final video summarizing some of the key concepts of the whole course. We won't try to recap everything, but just hit the high points, so our journey through the course, a road map, as it were. So the quotes of the week though, for this week, are actually particularly apt, in terms of some of the things we'll be talking about. The first one is, if the facts don't fit the theory, change the facts. And this probably wasn't said by Einstein, but it certainly could have been said by him, as we'll see in some of our final comments when we talk about these crucial experiments. Another comment, he says, it strikes me as unfair and even in bad taste to select a few individuals for boundless admiration, attributing superhuman powers of mind and character to them. This has been my fate. And the contrast between the popular assessment of my powers and achievements and the reality is simply grotesque. And so again, that will come into play over, keep that in mind when we talk about, in your final comments, the nature of genius. Certainly in some respects, we'd say Einstein was one of the supreme geniuses of all time in terms of scientific thought. But he had a somewhat different view of his powers and achievements as it were. Then two other short ones here. When he was introduced to an 18-month-old baby, the baby screamed when introduced to him. And Einstein's response was, you're the first person in years who has told me what you really think of me. Again, when you're lionized like Einstein was, sometimes it's hard to have people actually say what they think around you. And then finally good advice for anyone is try to become not a person of success but try rather to become a person of value. And with that more solid foundation, success in various ways will usually occur. So those are the quotes of the week. Here's where we're heading. And so in the next video, we'll talk about traveling the galaxy.