Hesperus Descending

In Manhattan, the beauty of the night sky is only a faded metaphor, the shopworn verse of an outdated love song. The stars shine no brighter at midnight in midtown than the ones depicted on the time-dimmed ceiling of the main concourse at Grand Central Terminal. But over the last few weeks it has been possible, even in Manhattan, to watch the evening star -- Venus -- descending in the west, presenting her orbit, edgewise, to viewers on Earth.

Venus is the luminous body hanging over New Jersey in the early evening, brighter than any heavenly object visible from Earth except the sun and the moon. For the moment, Venus becomes apparent at twilight, about a third of the way up the western sky, and it sets around 11. Every night people go to bed wondering what strangely bright star that is. In the morning no one remembers the question any longer.

To say, as one must, that Venus is not a star but a planet seems ungrateful, almost pedantic. It is the kind of technicality the English essayist Charles Lamb had in mind when defending the generosity of his personal ignorance almost 200 years ago. "I guess at Venus," he wrote, "only by her brightness." Lamb was no Copernican, and neither are most of us. We are little Ptolemies every one. The sun rises and sets upon us while the earth remains fixed beneath our feet. When one lies upon a meadow late at night, etherized by the fullness of the sky, it is all one can do to imagine the simplest of celestial motions -- the pivoting of constellations around the North Star. To impart to each point of light the motions that are proper to it -- to do the unimaginable calculus of all those interfering rotations, those intersecting gravities -- is simply impossible. It is easier to imagine that one is staring at the ceiling of a celestial concourse.

But at the moment, one can almost picture the motion of Venus in its orbit, as if one were looking at a diagram of the solar system. Imagine a line between the sun, at sunset, and Venus, glittering high above the horizon. That, roughly speaking, is the path of the Venusian orbit. When Venus moves toward Earth, as it is doing now, it is the evening star, and when it moves away from Earth, it is the morning star. The moment of transition will occur on June 10, when Venus passes between the sun and Earth. As May wears on, Venus will appear nearer and nearer the sun, until the planet is engulfed by twilight. Venus will come back into view, at dawn, sometime in late July.