Timelines you can cite and check

Exact times, sources on every moment, and how precise each date is, in files you can export and keep.

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Example timelines

Deep time: 4.5 billion years of Earth

@athan · Changed 27 Oct 2026

Earth's history on one line, from its formation to a single second in 1969. Eons and eras are durations in the colours of the International Chronostratigraphic Chart; times are exact offsets from 2000 CE, shown in millions of years.

Size: 17 moments
Span: -4540 – -0.0000304 million years

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The history of computer science

@athan · Changed 27 Oct 2026

From counting boards and the first algorithms to deep learning: the theory, machines, languages, algorithms, systems, networks, software practice, security and AI that make up computer science, in calendar dates. Moments are tagged and col…

Size: 87 moments
Span: 2700 BCE – 2022 CE

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IBM's Deep Blue, the chess computer that defeated Garry Kasparov in 1997, on display at the Computer History Museum

The history of artificial intelligence

@athan · Changed 28 Oct 2026

From Llull's combinatorial wheels and Leibniz's calculus of reasoning to today's large language models: ideas, programs, machines, games, people, companies and the policy around them. Moments are tagged (symbolic AI, machine learning, neur…

Size: 82 moments
Span: 1305 CE – 2025 CE

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Explore all public timelines

Watch

Play: Timeline software for research, with sources and exact dates

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What you can do

Record times exactly. Times are whole numbers or fractions, never rounded when you save or export. Show them as Gregorian dates, Julian years, millions of years, SI units such as 1.5 ks, or a format you script yourself.
Cite every moment. The Sources plugin keeps a moment's or duration's source links. Dating context says whether a date is a day marker or an estimate, and Historical dates keeps the date as the source gives it, such as a Julian date, beside the timeline's own.
Search and link. Search a timeline's titles and notes, and link to any moment, duration or search.
Compare datasets. Stack timelines on one axis, with a scale and offset for each, to line up ones that count time differently.
Export in open formats. An .ochx file is JSON with everything in the timeline, including its display settings and plugins. The desktop app saves .och SQLite files, and the HTTP API reads and writes timelines with an API key.

What you can count on

Nothing is rounded. A third of a second stays exactly a third, however far you zoom.
Notes never move data. Editing a date's precision or its original calendar never changes the moment's time.
Every save is kept. Each save to the server is a revision, listed under History, that you can open and export.
Run it yourself. Install a server for your group, or use the desktop app or the offline file without one.

Also for

Educators
Class timelines that students add to and you review.
Investigators
Events and causal factors, with sources and a history of every change.
Operations
Syslog, journald and log files, live and at their exact times.
Writers
Story timelines and canons, in your world's own calendar.
Developers
The HTTP API, keys, plugins and self-hosting.