We close in. From one million kilometers the Earth-Moon system make a pretty pair set against the blackness of space. They look like they have always looked: a blue-white marble and a chunk of grey rock, much smaller than its primary.

We continue to close in. From one hundred thousand kilometers Earth is a small orb, still smaller than a fist held at arm's length. We recall how fragile our world is. Earth is a nest, and all the eggs of humanity, back in our time, are contained within it. A fist held at arm's length can cover it up; a small change in solar output, or a vagabond body can freeze it, burn it, hurl it away from the sun, or smash it to bits.

At ten thousand kilometers, the continents and cloud patterns become visible. The blues of the oceans, the white wisps of cloud formations, the greens and browns of the land ...

Something is wrong. As we pull into geostationary orbit thirty-five thousand, seven-hundred kilometers above North Africa, we see the continent outlines seem to be shifting; sometimes when we look they make one formation; sometimes they make others. The oceans appear to be receding and flooding spontaneously, chaotically. The color of the land, too, seems to be changing, from green to green-brown to brown to black to green again ... as if we were watching a slide show and someone mixed all the slides together, and now we have to make the sense out of it all for ourselves.

The future Earth is "fuzzy." This is a quantum mechanical effect; we are observing a wave function: a composite of all possible results. We cannot collapse the wave function (and see what the Earth will really be like in 2091), because we are not really here. We see a superposition of every possible Earth that there is, allowing for every possible event that causes a change from present time to 2091.

The "fuzziness" comes from trying to predict the future. The future is all probabilities. No one can say what Earth will be like; but anyone can say what it might be like, and every proposition is equally "valid." Only time will tell what the Earth will look like in a century, or a decade, or tomorrow; only waiting will determine what it really is like, as we collapse wave functions.

But we can still look at the possible Earths in 2091 AD

But we are not concerned with these Earths. At any rate, back in 1991 we know these Earths not to correspond with ours -- we do not see dinosaurs blinking on and off in our vision now. In some other parallel universe they exist (or so the Everett -- or "manyworlds" -- interpretation of quantum mechanics tells us), but not in the Universe we inhabit. Indeed, in many other universes the Big Bang itself never happened or happened differently, and so the laws of physics themselves are different. According to some of these laws, atoms cannot form, and so life itself is impossible -- certainly a depressing prospect. But these certainly do not reflect our Universe.

We've collapsed wave functions -- solidified the real from the imaginary -- merely be observing the world around us, and eliminated the possibilities of intelligent dinosaurs, the lifeless Earths, and the Big Bangs that were in actuality Small Puffs. Looking at the conglomerate of Earths in 2091, we concentrate on those that will come out of our world -- Earth in 1991.

A portion of these "conventional" Earths -- the ones that are similar, at least in basic form, to ours -- are overpopulated, diseased, poisoned, polluted to the point of toxicity. If population continues to increase, exponentially, unchecked at the rate it is now, then in 2091 the world population of Earth will be 35 billion. In the most pessimistic versions of this Earthtype, the seas are filled with sludge and garbage, and will be rising to drown everything, because of greenhouse effects; the air is brown and filled with unburnt hydrocarbons, acids, and other compounds typical of industrial pollution; the average temperature is dozens of degrees higher due to greenhouse effects. It is unlikely that life would last much longer in this scenario -- the destruction of the biosphere is far past the point of no return. A change in humanity's ways at this point would not stop the coming doom.

A smaller fraction are more optimistic. On some worlds technology has saved our descendants -- whether it take the form of a pollution-eater -- gene-tailored bacteria that consume waste and release oxygen (and possibly energy that we can use) -- or the form of a device which can convert matter directly to energy, yielding enormous energies and zero waste. (On some of these worlds, however, a new kind of pollution has come into play -- heat pollution.) Unfortunately, we cannot count on technology to rescue us this time.

But not all of the conventional Earths we see are absolutely beautiful or frighteningly horrible. The largest portion, probably, are more like our world today -- population just threatening to get out of hand; pollution just threatening to become dangerous. People have the unnerving tendency to address a problem only just before it becomes an epidemic, and even then only to half-heartedly tend to it: guaranteeing that a decade or two down the line, it will once again rear its ugly head.

Some of these Earths also have room-temperature superconductors, or at least use superconductors (room-temperature or not) in main trunk lines. Now not only is the power cheap and safe, but it is efficient as well -- there is little power lost to heat or resistance in wires. Will these technologies, which almost certain are waiting just around the corner, save us from environmental problems? Probably not. But they mean that pollution from powerplants is probably going to be less of a problem in the future.

But the most important environmental dangers are not powerplant emissions. Among them are greenhouse gas emissions -- gases which cause the "greenhouse effect," heating our planet up; vehicular and industrial pollution; ozone problems; overpopulation.

The prospect of these Earths are promising, but alas, we must realize that they are probably not likely, at least within our lifetime. Countries hold onto their power and sovereignty too hard to let a "higher authority" dictate what they can and cannot do. But one day we will have to adopt this kind of philosophy. It's just a matter of when -- in a year, a decade, or -- as our crystal ball gazing tells us -- a century.

But are these worlds desirable? Are we facing paradise only if we begin to act now? Perhaps. The planet management authorities (on most Earths it is like the UN -- delegates from all countries, since one country that gained a majority in the PMA could have an advantage over others) of these worlds execute their mandates in different ways. On some worlds they penalize countries not following their emission guidelines by imposing sanctions; on some more drastic Earths they move troops in. (The threat of violence, we realize, must be included at some point. A country is unlikely to follow PMA guidelines if they cannot be enforced.)

A committee in charge of deciding who can have children (Larry Niven called it the Fertility Board) is in place on many of these worlds, since population increase must be checked. Would you like the government dictating if you can or cannot have children? ... Yet it must be done. Some PMAs enforce this by giving tax breaks to people who follow their guidelines, and fine people who do not. Some are less lenient: a slap on the wrist, which of course would mean nothing. The more hostile PMAs take the child from the parents; some forcibly sterilize the illegal parents. Others execute the child. Still others execute the parents.

But on the whole the more lenient worlds with planet management authorities seem benign. Possibly a terminal for every citizen, in connection with networks which cover the planet -- and some have space stations, the Moon, and other planets as well, connected into Worldnet. Life is clean. Work is cerebral: robots and machines do all the manual labor, and humans do the thinking. Every person has a voice. Perhaps as countries learn more about their respective peoples, the boundaries between countries will begin to disintegrate: and these Earths are a "global village" (as it has been phrased).

Utopia? Perhaps things are not so beautiful on the inside as they seem on the outside. Perhaps life is so repetitive, without responsibilities or worries, that people are like insects ... they eat and drink, they eliminate, they sleep. But little else. Perhaps addictions are common -- not just to drugs, but to anything else that can break the monotony: sex, sleep, food, networking, even music and other seemingly harmless endeavors.

On others of these "utopias" the system is rotting from the inside out. Crime is common. Happiness is not.

Inevitable? Certainly not ... but possible? Absolutely.

Some Earths have spread out into the solar system. Some are actively exploiting the massive amount of raw materials in the form of high-grade metal ores in the asteroid belt; some have gone to the massive gas giants to collect hydrogen and helium and other gases. Some are even now settling planets around other stars ... but probably not very many. Interstellar travel is an expensive and unprofitable business -- Earth probably cannot expect colonies to return their investment, and probably can expect rebellions to set up sovereign states ... and Earth could not do anything about it, without faster-than-light travel. (A punishing force would be horribly expensive and probably fruitless. It would take decades to arrive: the colony that rebelled might very well be extinct, or reverted back to ally status, or might forget about their rebellion altogether.)

Some Earths have met extraterrestrial intelligences. Many of these Earths have struck upon a mutually-beneficial relationship, and there are "aliens walking among us." Most alien ships entering our solar system came as friends. Some did not. Some wiped out Earth's population altogether, or enslaved it ... and some Earths are fighting for their lives even as we watch, in 2091.

A very few have made drastic technological advances -- some Earthers are flitting across time itself via the parallel universes; others have invented devices to warp space and allow instantaneous travel (and some of these have made drastic errors and destroyed the fabric of spacetime, and the rest of the Universe with it).

In almost every possible Earth people are exactly the same. Homo sapiens sapiens: an intelligent, bipedal, immature primate (characteristics of humans are very similar to those of pre-adult apes and gorillas) with an insatiable curiosity and an intense desire to learn and to understand. Humanity is not going to go away, not in the short term. Even on the drastic worlds -- those where a nuclear war has taken place, or aliens have taken over -- humanity will likely not be wiped out, only set back (although perhaps forever).

What about the countries, though? Will the divisions of the world be the same as they are today?

Yes, and no, and maybe. (According to quantum mechanics, the Universe contains a maybe ...) In a number of Earths, very soon from now, the Soviet Union becomes completely capitalist. Perhaps in 2091 the Soviet Union (they may very well change their name back to Russia or some other name that we 20th century dwellers would not understand) will be outproducing every other country in economic, technological, and social markets ... in some the United States goes bankrupt, and Americans are the feared and despised immigrants to other countries.

But, again, in most future Earths things are basically the same as they are now -- or at least they face the same problems, though perhaps not in exactly the same ways and numbers. The country outlines might change a little, and some of the names and alignments may change, but overall it will be the same situation as it is now: countries with people of all nationalities, creeds, and races ... all competing for time and money and food, and all wary of each other. And all wondering what the future will bring.

But which of these Earths will we give our descendants? We cannot avoid some of these possibilities -- but we can try to avoid all of them. If we act now. This is not a new warning; people have been warning about the future for centuries. Many have been mistaken, or at least misled. They emphasized the wrong aspects, or jumped to the wrong conclusions, and no one listened.

But things are different now. Science has shown without a doubt that things will go from bad to unimaginably horrible -- if we don't do anything about them. Now. We've got plenty of problems to contend with -- and none of them have an easy, cost-effective solution (or they'd have been implemented already). Yet we must solve them.

But which planet will we inherit? "Maybe," the Universe answers, ambiguously.