The planet Venus, which has been blazing high in the western sky since late winter, is now descending into the sunset. On Tuesday, beginning at five in the afternoon, our closest planetary neighbor will cross the face of the sun.

Those of us who wish to observe this not-to-be-repeated-in-our-lifetimes event must use the same precautions that were recommended for viewing the recent solar eclipse: smoked glass, a sun filter (my choice), or indirect projection. Direct, unshielded viewing of the sun can seriously and permanently damage eyesight.

Having taken proper precautions, we sky-gazers will be able to see, with the aid of binoculars or a small telescope or even, I am told, with the unaided (but shielded) eye, a planet almost the same size as our Earth crossing the face of our local star. Such an event will not happen again until 2117, when none of us will be around to see it. So it's now or never; see it on June 5, or never again.

Whatever, as my resident 17-year-old might say. Why should something that will happen 40 million miles away distract him from more important local concerns, his girlfriend of the moment, cool cars and his chronic cash flow problem? Why should his more serious elders pause in their efforts to prohibit gay marriage or tax the rich, and watch the skies?

In a word, perspective.

Consider this: Although such a transit will not occur again in our lifetimes, transits of the inner planets across the face of the sun are common occurrences in our solar system's more spacious time frame.

They have happened more than 20,000 times during the estimated lifespan of the human race, and more than 40 million times during the lifetime of the Earth. By my calculations, transits of Venus have occurred 54 times since the beginnings of human history, and only once before, in 2004, during my own history. Man that is born of woman does indeed live but a little while.

Or let's take another word, proportion. Venus is almost exactly the same size as our Earth, but silhouetted against the sun it is as a BB to a basketball. And lest we imagine our sun, known in astronomical circles as a "yellow dwarf," is some kind of supergiant, let us remember that Old Sol is to a real supergiant like Antares as a BB is to a beach ball.

Yet even Antares is composed, as are we, of atoms so much smaller than the photons by means of which we see that they are invisible to our eyes. And these atoms are composed of much smaller subatomic particles, which are composed of yet smaller quarks, which are, so we are told, composed of vibrating superstrings a billion times smaller than the smallest atom.

The universe does seem to go down as far into the small as it goes up into the large, and our solar system, which has endured for five-thousand-million years, seems good for another five-thousand-million more. And here we are, improbably yet exactly in the middle of all this time and space, living lives that we call normal, lives to which we feel entitled.

In other words, the sight of this tiny Earth-sized point of rock passing across the sun can pop our bubble of the ordinary and leave us beholding the wonder and mystery and sheer improbability of our lives.

It is said that, in the last summer of his life, John Adams pointed to a flowering shrub and told his son that the queen of France in all her jewels could not compare with this simple thing. Now even the smallest thing, he said, can send his imagination to roaming the Milky Way.

"Rejoice ever more," he cried out, doing an arthritic dance. "Oh that this had been ever on my tongue and in my heart. Rejoice ever more."

And so on the fifth of June, all you libertarians and progressives, you Tea Party and Occupy Wall Street activists, drop what you're doing and behold a small thing, a world as improbable as our own, crossing the face of our unlikely local star.

And rejoice.

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Michael Nesset, of North St. Paul, is a teacher.