From time to time in this blog, I take a moment to celebrate fine writing. Here is an example I came across in an article in Smithsonian magazine from May 2014.
The author, Corey Powell , was trying to explain how astronomers use gravitational “tug” to indirectly reveal the existence of planets. In other words, they can’t see the planets, but they know that they are there. But how do they know it? Here is his analogy:
Picture a black dog at nighttime, yanking on its owner’s leash. The only way you can tell the dog is there is by the owners herky-jerky movements.
What a brilliant way to illustrate this important scientific concept.