Along with solutions to old puzzles, however, come new riddles, as most of our Universe appears to be in the form of some kind of unseen "dark matter" and incomprehensible "dark energy" whose natures and origins remain unfathomable. Yet with all our questions - and knowing that there are questions still to be asked - we have learned the most important lesson: that all of this Universe is our home, that it took all of it to make us, that it is ours to behold and enjoy.While this course stands on its own, it is also an ideal complement to the first course of the set (Astronomy: Earth, Sky, and Planets), which covers celestial motions, constellations, telescopes, and planetary astronomy, all of it then integrated into a full picture of space and time.