Where the Names Run Out

scalemetrologyepistemologywebgl

Sixty-five steps, each one ten times smaller than the last, from the largest unit the metric system has down to the Planck length. Nothing in between is skipped.

The names run out before the world does. That largest unit — the quettametre — describes nothing that exists: the observable universe, everything near enough for its light to have reached us, is a thousandth of one. And the smallest, the quectometre, still leaves sixty thousand times further to fall. Every step is drawn according to how we actually know what is there: photographed, measured, or only inferred.

quettametre · names nothing
1 × 10³⁰ m
1 quettametre
extrapolation
QuettametreCGPM 2022

The largest prefix ever coined. Nothing has ever been this big.

29.8 orders of magnitude larger than you

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The descent starts on its own; take it over by scrolling, dragging the image, dragging the ruler, or using the arrow keys. Travel is linear in log space — every decade costs the same. The empty stretches are not skipped.

How the image was made
  • extrapolation beyond the horizon — unobservable in principle, not merely unobserved
  • survey positions reconstructed from redshift and statistics, never photographed in one frame
  • light formed by visible photons landing on a detector — a photograph exists
  • instrument measured, but the image is a computed map — electron microscopy, scanning probe, crystallography
  • scattering no image at any resolution — a cross-section, a form factor, a charge distribution
  • theory never probed — nothing here has been measured, by anyone, ever
Sources
  • CODATA 2022 — CODATA Internationally Recommended Values of the Fundamental Physical Constants, 2022 adjustment. link
  • PDG — Particle Data Group, Review of Particle Physics — compositeness and substructure limits. link
  • Planck 2018 — Planck Collaboration, Planck 2018 results VI: Cosmological parameters. Comoving distance to the particle horizon. link
  • CGPM 2022 — 27th General Conference on Weights and Measures (2022), Resolution 3: extension of the range of SI prefixes. link
  • NASA/JPL — NASA/JPL planetary and solar system fact sheets. link
  • Abbe criterion — Abbe diffraction limit, d = λ / (2 NA). For violet light at NA 1.4 this is ~143 nm; practical optical systems land near 200 nm.
  • PDB / crystallography — Protein Data Bank and standard crystallographic constants for molecular geometry. link
  • Gaia DR3 — ESA Gaia Data Release 3 — stellar distances and Galactic structure. link
  • Natural Earth — Natural Earth 1:50m land vectors, public domain. Rasterised to Earth's coastline mask by scripts/build-earth-mask.py. link
  • Terrain Tiles — AWS Terrain Tiles (terrarium encoding), derived principally from SRTM. Elevation pyramid centred on Everest, built by scripts/build-terrain.py. link
  • derived — Derived from other listed sources by the stated relation; the relation is given in the anchor note.
Reading the numbers

Every size here is written as a power of ten. 10310^3 is a thousand — a one with three zeros after it. 10−310^{-3} is a thousandth. The raised number just counts the zeros, and it is the only notation that can hold both ends of this page on the same line.

The metric system gives those powers names, and you already use several: the kilo in kilometre is 10310^3, the milli in millimetre is 10−310^{-3}, the nano in nanometre is 10−910^{-9}. There are twenty-four in all, part of the international standard known as the SI, and the outermost pair are recent — quetta, 103010^{30}, and quecto, 10−3010^{-30}, were both coined in 2022.

Neither end fits the thing it was built to describe. The observable universe — the whole region close enough that its light has had time to reach us — measures 8.8×10268.8 \times 10^{26} metres, roughly a thousandth of a single quettametre. The Planck length is 1.616255×10−351.616255 \times 10^{-35} metres, about sixty thousand times smaller than a quectometre. The notation overshoots at one end and runs out at the other.

What the colours are claiming

Almost nothing on this page was seen. Most of it could not have been.

So every scale carries a tag for how an image there is actually produced, and the way it is drawn follows from that tag rather than decorating it. The coloured strip beside the visualisation is a map of those tags — it shows, before you travel anywhere, how much of the ladder is photograph and how much is inference.

Where photography stops. Light cannot resolve detail much finer than its own wavelength. In practice that limit lands near 2×10−72 \times 10^{-7} m, two ten-millionths of a metre — the Abbe limit, d=λ/(2 NA)d = \lambda / (2\,\mathrm{NA}), which for violet light through a good lens works out at roughly 143 nm. Below that no photograph has ever been taken, or can be.

Where structure stops. Below 10−1010^{-10} m there is nothing left to picture. An electron orbital is a probability density — a description of where the electron is likely to be found — not a picture of a thing sitting in a place. Below 10−1510^{-15} m there is not even a surface: what exists is a scattering cross-section, so every rendering of a proton, here and everywhere else, is a convention.

Where measurement stops. The smallest scale any experiment has ever reached is around 10−1910^{-19} to 10−2010^{-20} m, at the Large Hadron Collider. Between that floor and the Planck length lie fifteen powers of ten that no instrument has ever touched.

And where observation stops going the other way. Past 4.4×10264.4 \times 10^{26} m nothing can ever be seen. Not with better telescopes; not in principle. Light from further away has not had time to arrive.

Why the empty stretches are not skipped

Moving one step on the slider always multiplies or divides by the same amount. Crowded stretches and empty ones therefore take exactly as long to cross.

Almost every wrong intuition about scale is manufactured by pictures that quietly compress the empty parts to fit them on a page. From an atom’s nucleus out to the edge of the atom is five powers of ten of nothing at all: if the atom were a stadium, the nucleus would be a marble on the centre spot, and everything between would be empty.

Drawn honestly, that emptiness is most of the journey. It is the content, not the gap between the content.