This kind of appeal to reality as the ultimate arbiter of scientific disputes is anathema to some sociologists of science, whose work we will discuss briefly at the beginning of the next chapter. Successful discoverers often pursue a network of related enterprises. Still, the search for Planet X was one of the legacies he left the observatory. Clyde Tombaugh, who was hired by the observatory and given new equipment to search for Planet X, found Pluto at a position close to Lowell's predictions in 1930. The controversy raged for years.
Successful discoverers have to be lucky.
One can be persistent, have a mental model which prepares one to make a discovery and the best possible equipment, but still fail because there simply isn't anything to be discovered. Of course, even a failed search can generate lots of important information. Tombaugh continued to search for planets beyond Pluto, and he was able to determine that none existed above the 16th magnitude. This kind of negative information is very important. Obviously, one cannot teach students to be lucky, but one can remind them to be prepared to take advantage of surprises.