The Earth forms
Dust and rock around the young Sun gather into a planet. The figure comes from lead in meteorites and the oldest lead ores, and it is good to about 1%.
0 m along the pathThe Walk
4.54 billion years, one metre at a time.
Every metre on this path is a million years. The whole walk is 4.54 km, about an hour on foot. One screen is 100 metres.
The Solar System’s first solid grains are older still, 4,567 million years, 27 metres behind where you are standing. Dates are from the official chart of geological time and the papers listed at the end.
The Archean eon begins4,031 Ma
The Proterozoic eon begins2,500 Ma
The Tonian begins1,000 Ma
The Cryogenian begins720 Ma
The Ediacaran begins635 Ma
The Phanerozoic eon begins538.8 Ma
The Ordovician begins486.85 Ma
The Silurian begins443.1 Ma
The Devonian begins419.62 Ma
The Carboniferous begins358.86 Ma
The Permian begins298.9 Ma
The Mesozoic era begins251.902 Ma
The Jurassic begins201.4 Ma
The Cretaceous begins143.1 Ma
The Cenozoic era begins66 Ma
The Neogene begins23.04 Ma
The Moon
Most researchers think a body about the size of Mars hit the young Earth, and the Moon formed from the debris. When exactly is still argued over, so take this date as rough.
40 m along the pathThe oldest piece of Earth
A grain of zircon smaller than a full stop, found in Jack Hills, Western Australia. Its chemistry hints that there was already liquid water on the surface.
136 m along the pathThe oldest rock
The Acasta Gneiss in northern Canada. The start of the Archean eon on the official chart is set by this rock’s age.
509 m along the pathLife, in reefs
Layered mounds built by microbes in shallow water, preserved in the Pilbara of Western Australia. Older claims exist, but these are among the best accepted.
1,110 m along the pathOxygen in the air
Microbes have been making oxygen by photosynthesis, and now it starts to build up in the air. It took about 200 million more years to stay for good.
2,110 m along the pathSnowball Earth
Ice reaches the tropics, perhaps the whole planet. It happens twice: about 717 to 660 million years ago, and again in a shorter spell that ends about 635 million years ago. The Cryogenian period is named after it.
3,823 m along the pathAnimals everywhere
The Cambrian begins. Within a few tens of millions of years, almost every major animal body plan alive today has appeared in the fossil record.
4,001 m along the pathThe first great extinction
At the end of the Ordovician, an ice age drains the shallow seas and most species in the sea die out.
4,097 m along the pathEngland meets Scotland
By the late Silurian, the Iapetus Ocean that lay between the land that became England and the land that became Scotland has all but closed. The join lies deep under the Solway Firth area.
4,115 m along the pathBritain on the equator
For much of the Carboniferous, Britain lies near the equator. Tropical swamps leave the coal that later powered the industrial revolution.
4,181 m along the pathThe Great Dying
The worst extinction in Earth history ends the Permian. Most species in the sea and most on land are lost. Huge eruptions in Siberia are the leading suspect.
4,288 m along the pathThe first dinosaurs
Small, two-legged dinosaurs appear in the Late Triassic. For their first 30 million years or so they share the world with many other reptiles.
4,310 m along the pathDinosaurs take over
Another mass extinction ends the Triassic, and dinosaurs fill the gaps. The Jurassic begins.
4,339 m along the pathThe Jurassic Coast begins
The cliffs of Dorset and East Devon record about 185 million years of Earth history, from the Triassic to the Cretaceous. Mary Anning dug ichthyosaurs out of them at Lyme Regis in the 1800s.
4,355 m along the pathThe asteroid
A rock about 10 km across hits what is now Mexico. The non-bird dinosaurs, and about three-quarters of all species, are gone.
4,474 m along the pathMagnified
The last 3 metres
You are 4,537 metres along. Everything below happens in the length of a big stride.
- 2.58 million years ago · 2.58 m from the end
The ice ages
The Quaternary begins. Ice sheets grow and shrink again and again. At their largest they cover most of Britain.
- 300,000 years ago · 0.3 m from the end
People like us
The oldest known Homo sapiens fossils, from Jebel Irhoud in Morocco, are about 300,000 years old.
- 11,700 years ago · 11.7 mm from the end
The Holocene
The last ice age ends. Farming starts soon after. All of written history fits in the last 5,000 years.
Sources for this page
Boundary dates and colours are from the International Commission on Stratigraphy’s chart, version 2026/06, and the standard colour set that goes with it. Where the chart gives an uncertainty, the date is shown without it here; the chart has the details. The page’s background takes a pale tint of the current period’s colour.
- Age of the Earth US Geological Survey (Dalrymple)Earth is 4.54 billion years old, give or take about 1%
- The age of the Earth in the twentieth century: a problem (mostly) solved (2001) G. B. Dalrymple, Geological Society of London Special Publications 190How the 4.54 billion year age was reached from meteorites
- Age of meteorites and the earth (1956) C. Patterson, Geochimica et Cosmochimica Acta 10The first lead-isotope age of 4.55 billion years
- Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago (2001) S. A. Wilde and others, Nature 409The oldest known piece of Earth, a 4,404 million year old zircon from Jack Hills, Western Australia
- Priscoan (4.00–4.03 Ga) orthogneisses from northwestern Canada (1999) S. A. Bowring and I. S. Williams, Contributions to Mineralogy and Petrology 134The Acasta Gneiss, the oldest known rock, about 4,030 million years old
- International Chronostratigraphic Chart, v2026/06 International Commission on StratigraphyEvery boundary date for eons, eras, periods and epochs
- Stromatolite reef from the Early Archaean era of Australia (2006) A. C. Allwood and others, Nature 441Microbial reefs about 3,430 million years old in the Pilbara
- A 200-million-year delay in permanent atmospheric oxygenation (2021) S. W. Poulton and others, Nature 592Oxygen starts to build up in the air about 2,430 million years ago
- Snowball Earth climate dynamics and Cryogenian geology-geobiology (2017) P. F. Hoffman and others, Science Advances 3The two global glaciations, about 717 to 660 and about 650 to 635 million years ago
- Iapetus Suture, South of Scotland British Geological Survey, EarthwiseThe Iapetus Ocean closed and the two continents joined in the Silurian; the suture lies under the Solway area
- Bedrock Geology UK South: Carboniferous British Geological Survey, EarthwiseBritain lay just south of the equator early in the Carboniferous and a few degrees north later
- Dinosaur facts and the age of the dinosaurs Natural History Museum, LondonWhen dinosaurs first appear and which groups lived when
- Dorset and East Devon Coast UNESCO World Heritage CentreThe Jurassic Coast shows about 185 million years of Earth history
- The Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary (2010) P. Schulte and others, Science 327An asteroid impact at Chicxulub caused the extinction 66 million years ago
- New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens (2017) J.-J. Hublin and others, Nature 546The oldest known Homo sapiens fossils, about 300,000 years old
- Standard colour codes for the geological time scale (RGB set) Commission for the Geological Map of the World, via the Geologic TimeScale FoundationThe colour of every period and eon on the site