One interesting wrinkle of contemporary astronomy is that we're finding planets everywhere we look. It's now inescapable that there are more planets in the universe than there are stars.
And how many stars are there? Well, current estimates range from ten sextillion to 1 septillion. To get an idea of how big a septillion is, if you had been spending 1000 dollars a minute since the age of Charlemagne, and if your septillion dollars were in a bank making two percent interest, you wouldn't have touched the principal yet. Nor would you. Ever.
(I made that up, so don't break out the old calculator, but I think it's true, with a lot of change to spare.)
The point is there's an unimaginable number of stars, and that number is smaller than the number of planets. You could visit a different planet each second for a billion years and still have room in your passport for more stamps. Not to mention frequent-flyer miles like you couldn't believe. You could take a plane to work every morning and still not use them all up.
Of course, you wouldn't want to visit most of these worlds, and in fact you wouldn't survive your one-second drop-in on the vast majority of the ones we've discovered so far. Many of them are all gas, others are barren rocks, some are frozen at almost absolute zero, others are literally boiling. Some are boiling on one side and frozen on the other. Some of them are covered entirely in thick liquefied gases, a never-breaking tidal wave circling them, staying on the side facing their star as they rotate. Some are so big their gravity would instantly turn you into a glistening film a couple of molecules thick. Hundreds of millions of them don't even have a star to call their own; they got yanked out of orbit and floated away and now wheel silently through the freezing dark, waiting for some foolish space traveler to rear-end them. Some of them are exactly like Trenton, New Jersey. (With numbers--probabilities--as vast as these, it's hard to imagine any possibility that isn't going to be actualized somewhere.)
Making up for those planets that have deserted their stars, it's widely believed that about half the universe's stars are in binary or even trinary arrangements, orbiting each other, so zillions of planets have two or three suns. Some planets are so close to their sun that they gradually spiral into its surface. Some have suns that expand and contract, brighten and dim, regularly. Some planets cling hopelessly to radio stars, massive lightless objects that sizzle with radioactive energy, a kind of dark sunshine. Some of these planets, if the image below is to be believed, look like a marble orbiting a pizza.
When the discussion turns to exoplanets, lots of people want to cut to the biological chase: is life a local phenomenon, like the weather, or distributed through the universe? If it's the latter, how many of these newly-discovered worlds could sustain life? I think there are three or four possible motivations for this question: to find out whether we're alone in the universe; to raise a sticky issue for religious fundamentalism; to expand our dating possibilities; to hear how the other person might answer the question. Me, I don't much care.
As astonishing and full of grace as individual human beings can be, as a whole we're polluters and wastrels of the worst kind. It's hard for me to believe that the inhabitants of exoplanets are high-foreheaded, shimmering translucent beings who emit music as they move and think in benign algorithms. I'm more inclined to believe that they're a little like us, since we're all likely to be made out of the same materials. About the most I can work up is a mild interest in hearing the poetry and music from those worlds, learning whether their inhabitants have solved the problems of pain and death, and whether they've found a way to create political structures that, over time, don't ineluctably shed the principles that once inspired them and evolve into ever more efficient ways of exploiting the weak.
Nature, as Tennyson observed, is red in tooth and claw. But not on Mars, it's not. There's something pristine and crystalline about that still, silent stone-littered worldscape. I'll bet the vast methane ice-caves of Titan are breathtaking, if there were any breath in the vicinity to take. As we cut down the last of the old-growth forests, as we burn off the chaotic genetic tangle of the Amazon basin, as we kill each other over insane belief systems that were antiquated centuries ago, I sort of hope all those gazillions of planets, or at least most of them, are as untouched as the crystals in the center of an uncut geode. Just there. Emptiness is okay.
The planet we inhabit came into being about four and a half billion years ago, and life erupted on it about a billion years later. This means that the universe did just fine without us or our terrestrial forebears for ten and a half billion years. Things beyond our imagining expanded, condensed, formed, ignited, exploded, froze, boiled, and did the gravity dance with no supervision, or at least none I'm willing to accept. From the tiniest quark to the Great Attractor, everything seems to have worked as it should. And in addition to all that, it was beautiful.
So glisten away, exoplanets. Sweep through the heavens empty and immaculate. Let's hope no one is coming to plunder your treasures and darken your skies.
Tim -- Sundays