Even though
The Guide is supposed to serve as a “repository of all knowledge and wisdom” in the Galaxy, the book’s report of Earth is short and rather uninformative. Indeed, it’s hard to think of this single-word (and the new two-word) entry as actual “wisdom.” At the same time, it’s worth noting that knowing whether a planet is harmless or not is probably one of the first and most important things a galactic hitchhiker would want to know. In this way, the entry is rather effective, though it’s understandable that its brevity upsets Arthur, who is suddenly nostalgic for his home planet.