Most likely, this is the best-known picture of a flag ever taken: Buzz Aldrin standing next to the first U.S. flag planted on the Moon. For those who knew their world history, it also rang some alarm bells. Only less than a century ago, back on Earth, planting a national flag in another part of the world still amounted to claiming that territory for the fatherland. Did the Stars and Stripes on the moon signify the establishment of an American colony?