It took an additional 220 years before another of the greatest minds in physics, Albert Einstein, altered Newton's theory of gravitation further with his description of general relativity. Although the precision of general relativity is not required to describe many of the motions of the planets, one observational effect, the observed precession of the orbit of Mercury, eluded even Newton's mechanics and can only be explained using relativistic effects.

So now that man can predict the motion of the planets with remarkable accuracy, planetary conjunctions lose some of their mystique. In fact, using modern tools, such as Starry Night, we can see that planetary conjunctions are in a sense just optical illusions, visual alignments along arbitrary lines . . . serendipity at its finest!

So why, then, are amateurs still interested in conjunctions? Because they provide a chance to see several beautiful celestial objects all at once!