The Quiet Galaxy

Explanations · They were never there

We are early: the universe has barely started making civilisations, and we are among the first

Proposed by Robin Hanson, Daniel Martin, Calvin McCarter and Jonathan Paulson, with an earlier version by Abraham Loeb, Rafael Batista and David Sloan, 2021 fl smallerfi smaller

The universe is about 13.8 billion years old, but most of the stars that will ever shine have not yet been born, and the small, dim, long-lived stars that make up most of the galaxy will keep their planets warm for trillions of years. Measured against that span, we have arrived absurdly early. One reading is simple: civilisations are something the universe will do mostly in the future, and we are the first in our neighbourhood because there has not yet been time for many. A sharper reading, the "grabby aliens" model of 2021, says our earliness is itself a clue: we are early because if we were any later, someone expanding fast would already have filled our part of the sky and taken our place. Either way, the sky is quiet because the party has not started.

Two arguments share this page because they reach the same conclusion by different roads.

The first is a matter of timescales. Star formation in the universe peaked about ten billion years ago and has been declining since, but the stars being made now, and most stars already made, are small red dwarfs that will burn for hundreds of billions to trillions of years. If planets around such stars can carry life, then almost all the life-years the universe will ever offer lie far in the future. Abraham Loeb and his colleagues worked this through in 2016 and found that, counted that way, a typical civilisation should appear in the far future around a small star: the chance of life per unit of time peaks around the smallest stars some ten trillion years from now, at about a thousand times its value around the Sun today. A civilisation appearing now around a star like the Sun is early by a factor of about a thousand. Either red dwarfs are poor homes, which would make us typical, or we are among the first.

The second argument, from the economist Robin Hanson and three collaborators in 2021, starts from the same puzzle and adds the idea that advanced civilisations, once they appear, tend to expand and keep expanding, grabbing every star they reach and changing its appearance so that later observers can see where they have been. The authors call such civilisations grabby. If grabby civilisations exist, they set a deadline: any planet they reach stops producing new civilisations. The reason we see no grabby civilisations yet, and the reason we arrived so early in the universe's life, are then the same fact seen from two sides. We are early because the deadline is coming. The model fits three numbers together, how fast expansion goes, how many hard steps evolution must pass, and how early we are, and the fit says each grabby civilisation will eventually come to control somewhere between about a hundred thousand and thirty million galaxies, so they are rare; that they expand at over half the speed of light; that they already control something like 40 to 50 percent of the universe's volume; and that we could meet one in roughly 200 million to 2 billion years. Loud civilisations are thus rare, and the paper's title notes that quiet ones must then be rare too, since otherwise the loud ones would not be so few.

The bearing on the Drake Equation is through the factors that govern how often life and intelligence appear per planet per unit of time. The model does not say those steps are impossible, only that the whole chain is slow enough that very few planets have finished it yet. In the equation's terms it lowers the share of suitable planets on which life has started so far, and the share on which intelligence has appeared, while leaving open that both will be much higher a few billion years from now.

The objections are of two kinds. Against the timescale argument: red dwarfs flare, strip atmospheres, and lock their planets' rotation, so they may be poor homes, in which case we are not early but ordinary. Against the grabby model: it rests on the assumption that advanced civilisations expand and stay visible, which every explanation in the "unseen" family of this catalogue denies, and it uses the hard-steps picture of evolution, which is itself an argument from Earth's single history. The grabby model's defenders reply that the assumptions are explicit and the numbers that come out are testable, which is more than most explanations offer. The model also makes a striking prediction: when we do see a grabby civilisation, it will already be enormous, filling a large part of the sky, because anything smaller would be too young for its light to have reached us.

What it says about the equation

Every explanation is a claim about one or more of the seven pieces that are multiplied to give the number of detectable civilisations. This one bears on 2 pieces:

The test: what would strengthen or weaken it

Would strengthen it: Evidence that planets around red dwarf stars can hold atmospheres and water, which makes our early arrival harder to explain by chance; a deep survey finding no large-scale engineering anywhere in the visible universe, consistent with grabby civilisations not yet in view; further support for the hard-steps picture of the timing of evolution on Earth.

Would weaken it: Evidence that red dwarf planets are generally uninhabitable, which would make us typical rather than early; the discovery of an old civilisation nearby; the detection of a distant region of sky altered by an expanding civilisation that is small, which the model says should not be seen.

These two lines are what the record is read against when a new paper or discovery is logged. A result of the kind named here, published with its evidence, is what would settle it; a press claim on its own settles nothing.

The last reading

Once a week the records are read against the news, each against the test above. Open a line to see what that week held. Every reading ever made of this record is on the reading page.

  • 2026-10-16 Logged, no change By hand

    No update to the grabby-aliens model. On red dwarf planets holding atmospheres, the strengthening test: TRAPPIST-1 e is unresolved (Glidden and others, 2025-09-05) and the Rocky Worlds programme's GJ 3929 b result is unpublished on its own site. Against the hard-steps picture the explanation leans on, Mills and others (2025-02-14) argue the steps were not hard. Both logged.

    Glidden, 2025Mills, 2025 source 1source 2

How seriously it is taken

The timescale puzzle is widely accepted as real. The grabby aliens model is recent, discussed seriously, and admired for being precise and testable; it is not a consensus view, and critics question its assumption that civilisations expand and stay visible.

The papers that bear on it

Books, films and other work that take it up

Read next

Notes

Checked against sources on 2026-10-16. Corrected: (1) The grabby-aliens numbers. The abstract of Hanson, Martin, McCarter and Paulson (https://arxiv.org/abs/2102.01522; full text read from https://arxiv.org/pdf/2102.01522) says loud civilisations 'now control 40-50% of universe volume, each will later control ~10^5 - 3x10^7 galaxies, and we could meet them in ~200Myr - 2Gyr'; the conclusion says they expand at over half the speed of light. The text had said grabby civilisations appear 'about once per million galaxies' (the paper gives no such rate; the range of galaxies per civilisation is the nearest figure, and 'one-in-a-million-galaxies' appears there only in a remark about a 'rare Earth') and that they 'fill the universe within a few hundred million to a billion years' (the 200 million to 2 billion years is the time until we could meet one, not the time to fill the universe). The body now states the paper's figures. (2) Loeb, Batista and Sloan (https://arxiv.org/abs/1606.08448; full text read from https://arxiv.org/pdf/1606.08448): the paper says the probability of life per unit of time peaks around the lowest-mass stars (lifetime about 10 trillion years) at a value 'a thousand times larger than for the Sun'; the text had said early by a factor of 'a thousand or more', now 'about a thousand', and states what the thousand compares. The citation was filled out to 2016 (08), article 040 (doi 10.1088/1475-7516/2016/08/040). Confirmed with no change: The Astrophysical Journal 922, 182 (2021-11-30; Crossref doi 10.3847/1538-4357/ac2369); star formation peaked about 3.5 billion years after the Big Bang, which is about ten billion years ago (Madau and Dickinson 2014, Annual Review of Astronomy and Astrophysics 52, 415-486, https://arxiv.org/abs/1403.0007).

Think this page gets the explanation wrong, or misses an objection? Say so, or read how disagreement gets folded in. The record itself is data/explanations/we-are-early.toml in the public repository. This page's address will never change; if the explanation is ever retired, the address will say what replaced it.