The Pale Blue Dot
On 14 February 1990 Voyager 1 looked back from about 6 billion km and photographed Earth. Our planet was a dot smaller than a single pixel, and Carl Sagan named the picture the Pale Blue Dot.
Available views: Orbit ✓ · Sky — (not visible in the sky)
The story
On 14 February 1990, with its planetary tour finished, Voyager 1 turned its camera back toward Earth. The astronomer Carl Sagan had been asking for this picture for years. At that moment Voyager 1 was about 40.5 AU from the Sun and about 6 billion km from Earth, a distance light takes about five and a half hours to cross.
Earth looked tiny. According to NASA it filled just 0.12 of a pixel, less than a single pixel. And because the camera was pointed fairly close to the Sun, sunlight scattered inside the camera made bright streaks across the picture. Earth appeared as a faint dot sitting in one of those streaks.
That day Voyager 1 took 60 pictures in all. Together they showed six planets: Venus, Earth, Jupiter, Saturn, Uranus and Neptune. This set of pictures, looking back at the solar system from outside, is called the Family Portrait. Mercury was too close to the Sun, Mars reflected too little light to show up, and Pluto was too small and faint.
After these pictures, Voyager 1's cameras were switched off for good. There was nothing else for it to fly past, and its shrinking power supply had to be saved. Move the orbit view to 14 February 1990 and it reproduces where Voyager 1 was when it looked back, and how small Earth would have appeared from there.
Mission goals
As scientific data, the picture is not worth much. Earth is less than a pixel, and a streak of sunlight runs across the frame. It became famous not for what it shows but for where it was taken from. For the first time, people could see with their own eyes what Earth looks like from 6 billion km away.
Looking at the picture, Carl Sagan wrote: “Look again at that dot. That's here. That's home. That's us.” He meant that every person we know and all of human history have played out on that tiny speck. He expanded the idea in his 1994 book, Pale Blue Dot, and the picture is often shown alongside the message that we should take care of our planet.
Since then other spacecraft have also looked back at Earth from far away. On 19 July 2013 Cassini, orbiting Saturn, photographed Earth beyond Saturn's rings. NASA invited people to wave toward Saturn that day and called it “the day the Earth smiled”.
Mission chronology and background
Sagan first proposed the picture in 1980, after Voyager 1 had passed Saturn. It did not happen right away. Some felt there was little science to be gained, and there were worries that pointing the camera toward the Sun could damage its sensor. Only in 1989, after Voyager 2 had passed Neptune and it was decided to switch the cameras off, was the picture taken as a last chance.
The image of Earth was made by combining pictures taken through three filters: blue, green and violet. Each exposure lasted less than a second, between 0.48 and 0.72 seconds. The pictures were stored aboard Voyager 1 and sent back to Earth little by little between March and May 1990.
Where to see it — sky and simulator
Follow Voyager 1 in the orbit view and move the date to 14 February 1990 to reproduce its position at the moment of the photograph. It was above the plane in which the planets orbit, about 40.5 AU from the Sun. From there Earth appears very close to the Sun, which is why it ended up inside a streak of sunlight.
In 2020, thirty years after the picture was taken, NASA released a new version made by reprocessing the original data with modern methods. In the new picture the dot inside the streak is sharper and Earth's blue tint is easier to see. Both the original and the new version can be viewed on NASA's website.
See this for yourself — replay the moment in the orbit view
FAQ
How far away was it taken from?
On 14 February 1990, from about 6 billion km from Earth and about 40.5 AU from the Sun, a distance light takes about five and a half hours to cross.
How big is Earth in the picture?
According to NASA, 0.12 of a pixel, less than one pixel. It appears as a dot inside a streak of scattered sunlight.
Why was the camera switched off?
There was nothing else for it to fly past, and its shrinking power had to be saved. Voyager 1's cameras have not been used since.
Which planets are missing from the Family Portrait?
Mercury was too close to the Sun, Mars reflected too little light, and Pluto was too small and faint.
Related
- Voyager 1 launch
- Voyager 1 enters interstellar space
- Voyager 2 at Neptune
- Voyager 1 — object index
- Earth — object index
Times and figures are approximate — verify with official sources when planning travel. Simulation uses J2000 mean elements.