The Quiz: On average, the distance between the Earth and the moon is…
A Getting smaller
B Getting bigger
C Unchanging
The moon has an elliptical orbit, not a circular one, so sometimes it is farther away and sometimes closer. On average, the distance between the Earth and moon is about 239,000 miles. Yet that average distance is becoming greater all the time. The moon has drifted away from Earth since its creation and continues to do so at a rate of 1.5 inches per year. In theory, the lunar distance will continue to increase until the moon is so far away that a lunar orbit will take 47 days. At that point, the Earth and moon will have become tidally locked and the two bodies would have reached equilibrium. No need to adjust your calendar, though—it’s thought that this process would take around 50 billion years.
The correct answer to this quiz is Getting bigger.