The third planet

Earth

Every other world in this catalogue is somewhere you would die in seconds. This is the one where you can stand outside without a suit on, and the only reason is a shell of gas so thin it barely shows up when you draw it to scale.

art002e008486 - Commander Reid Wiseman looks back through an Orion window on the way to the Moon, April 2026. NASA titled the frame "Thinking of You, Earth".

An astronaut silhouetted against an Orion spacecraft window, looking back at Earth
01

Discovery

We came all this way to explore the Moon, and the most important thing is that we discovered the Earth.
Bill Anders, Apollo 8, 1968

Anders was not supposed to take that photograph. Earthrise was not on the flight plan, there was no procedure for it, and the crew had to scramble for a colour magazine while the Moon rolled underneath them. It became one of the most reproduced images ever made, and it is usually credited with starting the modern environmental movement.

The point was never the Moon. The point was the first time anyone looked back.

Between 1968 and 1972 about two dozen people were far enough away to hold the whole planet in one glance. After Apollo 17 came home in December 1972, nobody was - for more than fifty years. Every full-disc photograph in between was taken by a machine.

The hero image on this page is a person doing it again, out of a window, by hand.

The control

02

Three rocky planets formed in the same disc, out of the same material, within about forty million years of each other. Two of them are uninhabitable. Nobody is entirely sure why we are the exception.

Earth Venus Mars Surface temperature 15 °C average 464 °C, top to bottom -63 °C average Surface pressure 1 bar 92 bar 0.006 bar Atmosphere 78% nitrogen, 21% oxygen 96.5% carbon dioxide 95% carbon dioxide Liquid water Covers 71% of the surface Boiled off, then lost to space Ice at the poles, none flowing One rotation 23h 56m 243 days, backwards 24h 37m Magnetic field Global, and still running None Lost it, roughly 4 billion years ago Known life Everywhere we have looked None found None found
03

The thin part

Draw Earth to scale and the entire breathable atmosphere is thinner than the line you drew the planet with.

INTERNATIONAL SPACE STATION 408 km KÁRMÁN LINE - SPACE BEGINS 100 km EVEREST 8.8 KM AND A CRUISING AIRLINER 11 KM - THE SAME HAIRLINE 10 km SEA LEVEL EARTH, RADIUS 6,371 KM - DRAWN TO SCALE

Everything you have ever breathed sits in the bottom eight kilometres of that. Half the mass of the atmosphere is below the summit of Everest. On Venus the only layer at Earth pressure and temperature is fifty kilometres up, floating above a surface that would crush you.

Backing away

04

Five real photographs, ordered by how far the camera was from the subject. The frame gets smaller because the planet does.

  1. 408 kmLow Earth orbit - International Space Station

    Close enough that the aurora is beside the window rather than below it, and the curve of the horizon is something you notice rather than something you see.

    The aurora borealis over Earth, photographed from the International Space Station
  2. 45,000 kmApollo 17, on the way out - the Blue Marble

    The whole planet, fully lit, in one frame. Shot by hand out of a window five hours after launch, on a Hasselblad, by a crew who were not primarily there to take it.

    The Blue Marble, the full disc of Earth photographed by the Apollo 17 crew
  3. 384,400 kmLunar orbit - Apollo 8, Christmas Eve 1968

    Earthrise. Not in the flight plan, not on the checklist, and the reason anyone started arguing about the whole planet as one object.

    Earth rising over the lunar horizon, photographed from Apollo 8
  4. 1,500,000 kmLagrange point 1 - DSCOVR, continuously

    A camera parked at the gravitational balance point between Earth and the Sun, photographing the sunlit face once every couple of hours, indefinitely.

    The full sunlit disc of Earth photographed by the EPIC camera on DSCOVR
  5. 6,000,000,000 kmVoyager 1, 1990 - the Pale Blue Dot

    Everyone who has ever lived, in a single pixel, caught in a band of scattered sunlight. The camera was turned around for this and then switched off for good.

    The Pale Blue Dot: Earth as a single pixel in a beam of scattered sunlight, photographed by Voyager 1
Buzz Aldrin standing on the lunar surface, Apollo 11
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Moon

Three days out, a quarter of a million miles, and back. Six crews landed between 1969 and 1972, and the only piece of Apollo equipment you can still buy in a shop was the watch on their wrists.

Explore the Moon