The
Pale Blue Dot is
a photograph of planet Earth taken on February 14, 1990, by
the Voyager
1 space probe from
a record distance of about 6
billion kilometers
(3.7
billion miles,
40.5 AU),
as part of that day's Family Portrait series of images of
the Solar System.
In
the photograph, Earth's apparent size is less than a pixel;
the planet appears as a tiny dot against the vastness of space,
among bands of sunlight reflected by the camera.
Voyager
1,
which had completed its primary mission, was leaving the Solar
System. It was commanded by NASA to turn its camera around
and take one last photograph of Earth. Across the great expanse of
space, at the request of astronomer and author Carl Sagan, (the
phrase "Pale Blue Dot" was coined by Sagan) in his
reflections on the photograph's significance, documented in his
1994 book of the same name
In
September 1977, NASA launched Voyager
1,
a 722-kilogram (1,592 lb.) robotic spacecraft on a mission
to study the outer Solar System and eventually interstellar
space after the encounter with the Jovian System in
1979 and the Saturian System in 1980, the primary mission
was declared complete in November of the same year. Voyager
1 was
the first space probe to provide detailed images of the two largest
planets and their major moons.

The
spacecraft, still travelling at 64,000 km/h (40,000 mph),
is the most distant human-made object from Earth and the first one to
leave the Solar System. Its mission has been extended and
continues to this day, with the aim of investigating the boundaries
of The Solar System, including the Kuiper Belt,
the Heliosphere and Interstellar Space. Operating for
43 years, 10 months and 28 days as of 2 August 2021,
it receives routine commands and transmits data back to the Deep
Space Network.
Voyager 1 was
expected to work only through the Saturn encounter. When
the spacecraft passed the planet in 1980, Sagan proposed the idea of
the space probe taking one last picture of Earth.[8] He
acknowledged that such a picture would not have had much scientific
value, as the Earth would appear too small for Voyager's
cameras to make out any detail, but it would be meaningful as a
perspective on humanity's place in the universe.
Although
many in NASA's Voyager Program were supportive of the idea,
there were concerns that taking a picture of Earth so close to the
Sun risked damaging the spacecraft's imaging system irreparably. It
was not until 1989 that Sagan's idea was put into practice, but then
instrument calibrations delayed the operation further, and the
personnel who devised and transmitted the radio commands to Voyager
1 were
also being laid off or transferred to other projects. Finally, NASA
Administrator Richard Trudy interceded to ensure that the
photograph was taken. A proposal to continue to photograph Earth
as it orbited the Sun was rejected.
Voyager
1's
Imaging Science Subsystem (ISS) consists of two cameras: a
200 mm focal length, low-resolution wide-angle
camera (WA), used for spatially extended imaging, and a 1500 mm
high-resolution narrow-angle camera (NA) – the one that took Pale
Blue Dot –
intended for detailed imaging of specific targets. Both cameras are
of the slow-scan vidicon tube type and were fitted with
eight colored filters, mounted on a filter wheel placed in front of
the tube.
The
challenge was that, as the mission progressed, the objects to be
photographed would increasingly be farther away and would appear
fainter, requiring longer exposures and slewing (panning)
of the cameras to achieve acceptable quality. The telecommunication
capability also diminished with distance, limiting the number of data
modes that could be used by the imaging system.
After
taking the Family Portrait series of images, which
included Pale
Blue Dot,
NASA mission managers commanded Voyager
1 to
power its cameras down, as the spacecraft was not going to fly near
anything else of significance for the rest of its mission, while
other instruments that were still collecting data needed power for
the long journey to interstellar space
The
design of the command sequence to be relayed to the spacecraft and
the calculations for each photograph's exposure time were developed
by space scientists Candy Hanson of NASA's Jet
Propulsion Laboratory and Carolyn Porco of the University
of Arizona. The command sequence was then compiled and sent
to Voyager
1,
with the images taken at 04:48 GMT on February 14, 1990.
The
data from the camera was stored initially in an on-board tape
recorder. Transmission to Earth was also delayed by
the Magellan and Galileo missions
being given priority use of the Deep Space Network. Then, between
March and May 1990, Voyager
1 returned
60 frames back to Earth, with the radio signal travelling
at the speed of light for nearly five and a half hours to cover the
distance.
Three
of the frames received showed the Earth as a tiny point of light in
empty space. Each frame had been taken using a different color
filter: blue, green and violet, with exposure times of 0.72, 0.48 and
0.72 seconds respectively. The three frames were then recombined to
produce the image that became Pale
Blue Dot.
Of
the 640,000 individual pixels that compose each frame,
Earth takes up less than one (0.12 of a pixel, according to NASA).
The light bands across the photograph are an artifact, the
result of sunlight reflecting off parts of the camera and its
sunshade, due to the relative proximity between the Sun and the
Earth. Voyager's point
of view was approximately 32° above the ecliptic. Detailed
analysis suggested that the camera also detected the Moon,
although it is too faint to be visible without special processing.
Pale
Blue Dot,
which was taken with the narrow-angle camera, was also published as
part of a composite picture created from a wide-angle camera
photograph showing the Sun and the region of space containing the
Earth and Venus. The wide-angle image was inset with two narrow-angle
pictures: Pale
Blue Dot and
a similar photograph of Venus. The wide-angle photograph was taken
with the darkest filter (a methane absorption band) and the shortest
possible exposure (5 milliseconds), to avoid saturating the camera's
vidicon tube with scattered sunlight. Even so, the result was a
bright burned-out image with multiple reflections from the optics in
the camera and the Sun that appears far larger than the actual
dimension of the solar disk. The rays around the Sun are a
diffraction pattern of the calibration lamp, which is mounted in
front of the wide-angle lens.
Pale
blue color
Earth
appears as a blue dot in the photograph primarily because of Rayleigh
scattering of sunlight in its atmosphere. In Earth's
air, short-wavelength visible light such as blue light is scattered
to a greater extent than longer wavelength light such as red light,
which is the reason why the sky appears blue from
Earth. (The ocean also contributes to Earth's blueness, but to a
lesser degree than scattering.) Earth is a pale blue
dot, rather than dark blue, because white light reflected by clouds
combines with the scattered blue light.
Earth's reflectance spectrum
from the far ultraviolet, to the near infrared, is
unlike that of any other observed planet. And is partially due to the
presence of life on Earth Rayleigh scattering, which causes
Earth's blueness, is enhanced in an atmosphere that does not
substantially absorb visible light, unlike, for example, the
orange-brown color of Titan, where organic haze particles absorb
strongly at blue visible wavelengths.
Earth's
plentiful atmospheric oxygen, which is produced
by photosynthetic life forms, causes the atmosphere to be
transparent to visible light, which allows for substantial Rayleigh
scattering and hence stronger reflectance of blue light.
UAD
Voyager is how far away! Position of Voyager
1 on
February 14, 1990. The vertical bars are spaced one year apart and
indicate the probe's distance above the ecliptic.
According
to NASA's Jet Propulsion Laboratory’s HORIZONS tool, the
distances between Voyager
1 and
the Earth on February 14 and May 15, 1990, were as follows:
|
Distance
of Voyager
1 from
Earth
|
|
|
Unit
of measurement
|
February
14, 1990
|
|
Astronomical
Units
|
40.472229
|
|
Kilometers
|
6,054,587,000
|
|
Miles
|
3,762,146,000
|
Reflections
In
his 1994 book, Pale
Blue Dot,
Carl Sagan comments on what he sees as the greater significance of
the photograph, writes:
Look
again at that dot. That is here. That's home. That is us. On it
everyone you love, everyone you know, everyone you ever heard of,
human beings who ever was, lived out their lives. The aggregate of
our joy, and suffering, thousands of confident religions, ideologies,
and economic doctrines. Every hunter, and forager, every hero and
coward, every creator and destroyer of civilization. Every king and
peasant, every young couple in love, every mother and father, hopeful
child, inventor and explorer, every teacher of morals, every corrupt
politician, every "superstar," every "supreme leader,"
every saint and sinner in the history of our species lived there--on
a mote of dust suspended in a sunbeam.
The
Earth is a very small stage in a vast cosmic arena. Think of the
rivers of blood spilled by all those generals and emperors so that,
in glory and triumph, they could become the momentary masters of a
fraction of a dot. Think of the endless cruelties visited by the
inhabitants of one corner of this pixel on the scarcely
distinguishable inhabitants of some other corner, how frequent their
misunderstandings, how eager they are to kill one another, how
fervent their hatreds.
Our
posturing, our imagined self-importance, the delusion that we have
some privileged position in the Universe, are challenged by this
point of pale light. Our planet is a lonely speck in the great
enveloping cosmic dark. In our obscurity, in all this vastness, there
is no hint that help will come from elsewhere to save us from
ourselves.
The
Earth is the only world known so far to harbor life. There is nowhere
else, at least in the near future, to which our species could
migrate. Visit, yes. Settle, not yet. Like it or not, for the moment
the Earth is where we make our stand.
It
has been said that astronomy is a humbling and character-building
experience. There is perhaps no better demonstration of the folly of
human conceits than this distant image of our tiny world. To me, it
underscores our responsibility to deal more kindly with one another,
and to preserve and cherish the pale blue dot, the only home we have
ever known.
In
2015, NASA acknowledged the 25th anniversary of the photograph. Ed
Stone, Voyager project scientist, commented: "Twenty-five years
ago, Voyager
1 looked
back toward Earth and saw a "pale blue dot", an image that
continues to inspire wonderment about the spot we call home."
In
2020, for the image's 30th anniversary, NASA published a new version
of the original Voyager photo: Pale
Blue Dot Revisited
obtained using modern image processing techniques "while
attempting to respect the original data and intent of those who
planned the images." Brightness levels and colors were
rebalanced to enhance the area containing the Earth, and the image
was enlarged, appearing brighter and less grainy than the original.
The direction of the Sun is toward the bottom, where the image is
brightest.
To
celebrate the same occasion, the Carl Sagan Institute released
a video with several noted astronomers reciting Sagan's "Pale
Blue Dot" speech.
What is Voyager 1's distance from earth
today?As of early 2026, Voyager 1 is about
162–163 astronomical units (AU) from Earth.
Here’s what that means in more human terms:
Voyager 1 is moving away from the Sun at roughly 17 km/s
(~61,000 km/h), so it gains about 3.6 AU per year.
That’s why any quoted number is always an approximation—it’s
drifting farther every hour.
Context that makes the number hit harder:
It’s well beyond the heliopause, the
boundary where the Sun’s influence gives way to interstellar
space.
No human-made object has ever been farther from Earth.
The “Pale Blue Dot” image was taken at ~40 AU. Voyager is
now 4× farther away than it was then.