The Window: Why We May Be Living in the Moment of Firsts

A 500-Year Window in a 5-Billion-Year Road

The Sun has roughly 5 billion years of hydrogen-burning life left, so that is the outer limit on how long humanity could exist on or near Earth, and in practice it is much shorter: a brightening Sun is expected to boil away the oceans in about 1 to 1.5 billion years. Suppose the whole run were available to us. The 500 years around the present, in which we split the atom, left the planet, read and rewrote our own genome, and began building minds that are not biological, would be about 0.00001% of it. If a person were dropped into that span at random, the chance of landing in this particular window would be about one in ten million.

That is the puzzle. One reading is that the timing is luck. Another is that a civilization which has just crossed these thresholds is simply the kind that notices it has, and that few such moments exist. A third, which this issue explores, is that the window is short because the civilization inside it is short-lived. The rest of the issue is the evidence that these really are firsts, followed by what the Drake equation has to say about it.

What if L Is Short?

The Drake equation, written by Frank Drake for a 1961 meeting at Green Bank, West Virginia, multiplies seven terms to estimate how many civilizations in our galaxy are communicating at any moment. The last is L, the average length of time a civilization releases detectable signals. Drake's original estimate for L was 10,000 years, and modern guesses range from about 100 to 1,000,000. Because the equation is a product, L scales the answer directly: a shorter lifetime means fewer civilizations at once, even if life itself is common.

Three lines of argument point toward that possibility. The doomsday argument, proposed by astrophysicist Brandon Carter in 1983 and championed by John Leslie, says that a randomly chosen human is unlikely to be among the very first, so the total number of humans is unlikely to be vastly larger than the number born so far. Robin Hanson's 1998 essay "The Great Filter" notes that the sky looks empty, so something must keep dead matter from becoming a lasting, expanding civilization, and asks how much of that filter is still ahead of us. And a 2018 paper by Anders Sandberg, Eric Drexler and Toby Ord, "Dissolving the Fermi Paradox," argues that once the equation's uncertain terms are treated as wide distributions instead of point estimates, there is a substantial chance that we are alone in the observable universe, which removes the paradox without needing a short L.

None of this proves that our window is short. Each argument has serious critics, and the observer-selection reasoning behind the first is disputed. But it gives a way to read the timeline: if L is long, then finding ourselves in the first 500 years of a possible 5-billion-year run is a coincidence of about one in ten million. If L is short, this window is most of the story, and these firsts are not early signs of a long future but the main events of a brief one.

The Thread

Every item above is a first that cannot be repeated: the first controlled release of nuclear energy, the first complete genome, the first gene-editing drug, the first error correction that improves with scale, the first look at the early universe, the first deflected asteroid. They arrive within about 80 years of one another. Whether that clustering is chance, selection, or a sign of something short-lived is an open question, and this issue has tried to keep what is established separate from what is argued.

The one conclusion that does not depend on any of the arguments is that these thresholds, once crossed, stay crossed. What we do with them is the only part still undecided Opinion.