---
title: "Timestep · Library · Simulation Hypothesis"
url: https://simulation-hypothesis.com/library/timestep
description: "A timestep is the slice of simulated time between one update of a simulation and the next."
license: https://creativecommons.org/licenses/by/4.0/
credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)"
---

## Physics & computation

# Timestep

Definition

A timestep is the slice of simulated time between one update of a simulation and the next. Faster physics needs smaller timesteps: femtoseconds for atoms, attoseconds for electrons.

On this site

It’s why the Atom rung needs 10^15 updates per second for each atom.

Role in the model

Detail adds up twice: in how many things you track, and in how often you update them. Atoms need a new position every femtosecond, so an atom-level world runs at a quadrillion updates per second. That’s why finer matter floors take far more computing than the number of things alone would suggest.

Related

[Matter fidelity](https://simulation-hypothesis.com/library/matter-fidelity)[Molecular dynamics](https://simulation-hypothesis.com/library/molecular-dynamics)[Planck time](https://simulation-hypothesis.com/library/planck-time)

## The people behind the terms

14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading).

[Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers)