The entire Earth is but a point, and the place of our own habitation but
a minute corner of it.
As the astronomers unanimously teach, the circuit of the whole earth, which
to us seems endless, compared with the greatness of the universe has the likeness
of a mere tiny point.
The spacecraft was a long way from home, beyond the orbit of the outermost
planet and high above the ecliptic plane which is an imaginary flat surface
that we can think of as something like a racetrack in which the orbits of the
planets are mainly confined. The ship was speeding away from the Sun at 40,000
miles per hour. But in early February of 1990, it was overtaken by an urgent
message from Earth.
Obediently, it turned its cameras back toward the now-distant planets. Slewing
its scan platform from one spot in the sky to another, it snapped 60 pictures
and stored them in digital form on its tape recorder. Then, slowly, in March,
April, and May, it radioed the data back to Earth. Each image was composed of
640,000 individual picture elements ("pixels"), like the dots in a newspaper
wire-photo or a pointillist painting. The spacecraft was 3.7 billion miles away
from Earth, so far away that it took etch pixel 5.5 hours, traveling at the
speed of light, to reach us. The pictures might have been returned earlier,
but the big radio telescopes in California, Spain, and Australia that receive
these whispers from the edge of the Solar System had responsibilities to other
ships that ply the sea of space among them, Magellan, bound for Venus, and Galileo
on its tortuous passage to Jupiter.
Voyager 1 was so high above the ecliptic plane because,
in 1981, it had made a close pass by Titan, the giant moon of Saturn. Its sister
ship, Voyager 2, was dispatched on a different trajectory,
within the ecliptic plane, and so she was able to perform her celebrated explorations
of Uranus and Neptune. The two Voyager robots have explored
four planets and nearly sixty moons. They are triumphs of human engineering
an. one of the glories of the American space program. They will be in the history
books when much else about our time forgotten.
The Voyagers were guaranteed to work only until the Saturn encounter. I thought
it might be a good idea, just after Saturn, to have them take one last glance
homeward. From Saturn, I knew the Earth would appear too small for Voyager to
make out any detail. Our planet would be just a point of light, a lonely pixel,
hardly distinguishable from the many other points of light Voyager
could see, nearby planets and far-off suns. But precisely because of the obscurity
of our world thus revealed, such a picture might be worth having.
Mariners had painstakingly mapped the coastlines of the continents. Geographers
had translated these findings into charts and globes. Photographs of tiny patches
of the Earth had been obtained first by balloons and aircraft, then by rockets
in brief ballistic flight, and at last by orbiting spacecraft giving a perspective
like the one you achieve by positioning your eyeball about an inch above a large
globe. While almost everyone is taught that the Earth is a sphere with all of
us somehow glued to it by gravity, the reality of our circumstance did not really
begin to sink in until the famous frame-filling Apollo photograph of the whole
Earth, the one taken by the Apollo 17 astronauts on the last journey of humans
to the Moon.
It has become a kind of icon of our age. There's Antarctica at what Americans
and Europeans so readily regard as the bottom, and then all of Africa stretching
up above it: You can see Ethiopia, Tanzania, and Kenya, where the earliest humans
lived. At top right are Saudi Arabia and what Europeans call the Near East.
Just barely peeking out at the top is the Mediterranean Sea, around which so
much of our global civilization emerged. You can make out the blue of the ocean,
the yellow-red of the Sahara and the Arabian Desert, the brown-green of forest
And yet there is no sign of humans in this picture, not our reworking of
the Earth's surface, not our machines, not ourselves: We are too small and our
statecraft is too feeble to be seen by a spacecraft between the Earth and the
Moon. From this vantage point, our obsession with nationalism is nowhere in
evidence. The Apollo pictures of the whole Earth conveyed to multitudes something
well known to astronomers: On the scale of worlds (to say nothing of stars or
galaxies) humans are inconsequential, a thin film of life on an obscure and
solitary lump of rock and metal.
It seemed to me that another picture of the Earth, this one taken from a
hundred thousand times farther away, might help in the continuing process of
revealing to ourselves our true circumstance and condition. It had been well
understood by the scientists and philosophers of classical antiquity that the
Earth was a mere point in a vast encompassing Cosmos, but no one had ever seen
it as such. Here was our first chance (and perhaps also our last for decades
Many in NASA's Voyager Project were supportive. But from the outer Solar
System the Earth lies very near the Sun, like a moth enthralled around a flame.
Did we want to aim the camera so close to the Sun as to risk burning out the
spacecraft's vidicon system? Wouldn't it be better to delay until all the scientific
images from Uranus and Neptune, if the spacecraft lasted that long, were taken?
And so we waited (and a good thing too) from 1981 at Saturn, to 1986 at Uranus,
to 1989 when both spacecraft had passed the orbits of Neptune and Pluto. At
last the time came but there were a few instrumental calibrations that needed
to be done first, and we waited a little longer. Although the spacecraft were
in the right spots, the instruments were still working beautifully, and there
were no other pictures to take, a few project personnel opposed it. It wasn't
science, they said. Then we discovered that the technicians who devise and transmit
the radio commands to Voyager were, in a cash-strapped NASA, to be laid off
immediately or transferred to other jobs. If the picture were to be taken, it
had to be done right then. At the last minute actually, in the midst of the
Voyager 2 encounter with Neptune, the then NASA Administrator, Rear Admiral
Richard Truly, stepped in and made sure that these images were obtained. The
space scientists Candy Hansen of NASA's Jet Propulsion Laboratory (JPL) and
Carolyn Porco of University of Arizona designed the command sequence and calculated
the camera exposure times.
So here they are, a mosaic of squares laid down on top of the planets and
a background smattering of more distant stars. We were able to photograph not
only the Earth, but also five other of the Sun's nine known planets. Mercury,
the innermost, was lost in the glare of the Sun, and Mars and Pluto were too
small, too dimly lit, and/or too far away. Uranus and Neptune are so dim that
to record their presence required long exposures; accordingly, their images
were smeared because of spacecraft motion. This is how the planets would look
to an alien spaceship approaching the Solar System after a long interstellar
From this distance the planets seem only points of light, smeared or unsmeared,
even through the high-resolution telescope aboard Voyager. They are like the
planets seen with the naked eye from the surface of the Earth, luminous dots,
brighter than most of the stars. Over a period of months the Earth, like the
other planets, would seem to move among the stars. You cannot tell merely by
looking at one of these dots what it's like, what's on it, what its past has
been, and whether, n this particular epoch, anyone lives there.
Because of the reflection of sunlight
off the spacecraft, the Earth seems to be sitting in a beam of light, as if
there were some special significance to this small world. But it's just an accident
of geometry and optics. The Sun emits its radiation equitably in all directions.
Had the picture been taken a little earlier or a little later, there would have
been no sunbeam highlighting the Earth.
And why that cerulean color? The blue comes partly from the sea, partly from
the sky. While water in a glass is transparent, it absorbs slightly more red
light than blue. If you have tens of meters of the stuff or more, the red light
is absorbed out and what gets reflected back to space is mainly blue. In the
same way, a short line of sight through air seems perfectly transparent. Nevertheless,
something Leonardo da Vinci excelled at portraying, the more distant the object,
the bluer it seems. Why? Because the air scatters blue light around much better
than it does red. So the bluish cast of this dot comes from its thick but transparent
atmosphere and its deep oceans of liquid water. And the white? The Earth on
an average day is about half covered with white water clouds.
We can explain the wan blueness of this little world because we know it well.
Whether an alien scientist newly arrived at the outskirts of our solar system
could reliably deduce oceans and clouds and a thickish atmosphere is less certain.
Neptune, for instance, is blue, but chiefly for different reasons. From this
distant vantage point, the Earth might not seem of any particular interest.
But for us, it's different. Look again at that dot. That's here. That's home.
That's us. On it everyone you love, everyone you know, everyone you ever heard
of, every human being 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, ever 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 momentary masters of a fraction of a dot. Think of the endless
visited by the inhabitants of one corner of this pixel 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 posturings, 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
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've ever known.
"Because of the reflection of sunlight off the spacecraft, the Earth seems
to be sitting in a beam of light, as if there were some special significance
to this small world. But it's just an accident of geometry and optics. The Sun
emits its radiation equitably in all directions. Had the picture been taken
a little earlier or a little later there would have been no sunbeam highlighting
) passed away on December 7, 2016.
Because it is Christmas
month, here are the lyrics of his song:
They said there'll be snow at christmas
They said there'll be peace
But instead it just kept on raining
A veil of tears for the virgin's
I remember one christmas morning
A winters light and a distant choir
And the peal of a bell and that christmas tree smell
And their eyes full
of tinsel and fire
They sold me a dream of christmas
They sold me
a silent night
And they told me a fairy story
'till I believed in the
And I believed in father christmas
And I looked to the sky with
'till I woke with a yawn in the first light of dawn
saw him and through his disguise
I wish you a hopeful christmas
wish you a brave new year
All anguish pain and sadness
Leave your heart
and let your road be clear
They said there'll be snow at christmas
said there'll be peace on earthHallelujah noel, be it heaven
or hellThe christmas we get, we deserve
It’s alive! By firing a set of thrusters that have been gathering dust for more
than 3 decades, NASA has extended the lifetime of the
Voyager 1 mission by a few years.
The interstellar probe is 13 billion miles
away, moving at a speed of over 17 kilometres per second, but it still manages
to send messages back to Earth. In order to do that, it needs to keep its
antenna pointed towards us.
After 40 years in space, the thrusters that orient
the spacecraft and keep its antenna aiming in the right direction have started
to break down.
NASA engineers decided to try firing the craft’s backup
thrusters, which have been dormant for 37 years. Then, they had to wait 19 hours
and 35 minutes to get a signal from Voyager 1 at the edge of our solar system.
The long shot worked, and NASA scientists plan to fully switch over to the
backup thrusters in 2020.
The Voyager flight team dug up old records and studied
the original software before tackling the test. As each milestone in the test
was achieved, the excitement level grew, said propulsion engineer Todd Barber.
“The mood was one of relief, joy and incredulity after witnessing these
well-rested thrusters pick up the baton as if no time had passed at all,” he
said in a statement.
By switching out the thrusters, Voyager 1 may be able to
keep sending us messages for a little while longer, until around 2025. Launched
in 1977, Voyager 1 is the only spacecraft travelling through interstellar space,
the region beyond our solar system. Voyager 2 is close on its heels, nearly 11
billion miles from Earth. The thruster test worked so well that NASA expects to
try it on Voyager 2 in the future.