(electronic music)
- In 1977, NASA sent two golden records
into space aboard the Voyager One and Two spacecraft.
The Voyager probes have become two
of the farthest reaching objects ever launched by humanity.
And the golden records, real functioning LPs,
contained something utterly unique:
audio and images from Earth.
By 2030, both Voyager One and Two
will cease communications for good.
And while they won't be able to beam information
back to Earth, they're going to continue
sailing through space at almost 60,000 kilometers per hour.
The hopes are that one or even both
of these records will be intercepted
by another advanced civilization,
revealing a treasure trove of information
that will teach whoever finds them
about our pale blue dot of a home, light years away.
But in order for any one or any thing
to see the images contained on the record,
they'll have to decode this. (electronic tones)
And we're going to show you how.
(electronic tones)
(electric music)
If extraterrestrials do find the golden records,
the first thing they'll come across
is its cover which looks a lot like this.
It contains a handful of unique symbols
that properly explain how to play
the messages sent from Earth.
And at first glance, they're pretty complicated.
I tried to think how would an alien look at this picture?
And there are always two requirements.
You wanted things to be as easy
as possible to understand, as clear as possible.
But you also wanted in a limited number
of pictures to have as much information
as possible in each picture, so those
two requirements are kind of at odds.
That's Jon Lomberg, Carl Sagan's
long-time friend and collaborator.
Jon helped curate the contents
of the golden record and designed the cover.
- It's permeated the culture in a lot of different ways.
- The largest of the designs on the cover is the pulsar map.
It helps explain our location in the universe
by triangulating the Earth's distance
from various neutron stars, collapsed stars
that give off pulses of radiation or pulsars.
While this information doesn't help decode the record,
it would give anyone who finds it
a clue as to where it came from in the universe.
Every other symbol on the cover though
is there to explain how to properly play
the record and decode the audio.
Getting the songs and sounds
to play are pretty straightforward.
Figure out the correct rotation and speed
and they'll spin just like a normal record here on Earth.
Granted for an alien figuring out
how to work the record might be a challenge in itself.
- That should be very easy for them to discover.
But that's not all that's on the record.
And understanding the rest of it is a little bit harder.
- You might think that the images
included on the Voyager spacecraft
were printed out or included in some digital form.
But the golden record isn't a digital disc.
There are no jpegs or tifs included on it.
The Voyager's computer systems were only 69 kilobytes large,
barely enough for one image, let alone 115.
- And at that time in 1977 there
was no conventional technology
for putting pictures on adeline discs.
- NASA had to be a lot craftier
with the technology that they had available at the time.
Especially with the amount of data
they were looking to send and they managed
to encode that image data within
the audio waveforms themselves.
But in order for us to find that data,
we need to figure out the rest
of the symbols on the cover of the record.
Starting on the bottom right we
have a diagram depicting hydrogen,
the most abundant gas in the universe.
I spoke with Jacqueline Van Gorkom,
a professor of astronomy at Columbia University.
She explained to me that once in a blue moon,
the electron in a hydrogen atom
changes the direction of its spin.
- And so this transition which happens
spontaneously once every 10 million years,
it makes a little bit of energy.
So it emits at 21 centimeter wavelengths.
- The hydrogen atom depicted on the cover
of the record is undergoing that very unique change,
called a hyper-fine transition.
And what it emits, the 21 centimeter line,
is a very specific radio wavelength
that astronomers use to map the galaxy, 1420 megahertz.
- It's sort of mind-boggling.
- NASA uses that 21 centimeter line
as a constant for all the other symbols on the record.
If you convert that 1420 megahertz signal into seconds,
you get 7.042 times 10 to the negative 10 seconds.
Or .7 nanoseconds, and that one number
helps us unlock the rest of the record's symbols.
For instance here's a side-view of the record
that depicts this binary number around its diameter.
When converted to decimal and multiplied
by our hydrogen line constant,
we get 3229 seconds or roughly 53.82 minutes.
The total run time of the record from beginning to end.
And on the top-down view, converting
this binary number to decimal and multiplying
by .7 nanoseconds you get 3.59 seconds.
The time it would take for one rotation of the record.
So when we play the record that fast,
we should hear these sounds.
Greetings in 55 languages. (speaking foreign language)
Samples of music from around the world.
("Dark was the Night" by Blind Willie Johnson)
Sounds of Earth such as oceans,
birds, thunder and whales. (waves crashing)
And on the other side, this. (electronic tones)
It's that sound that contains all
of the image data for the photos
and drawings contained on the golden record.
And using the process described in the last few symbols
on the cover, we can render the images.
This is where things get really interesting.
The top right symbol shows how the waveform data
should be broken up with each section
of the waveform taking .008 seconds to play.
And according to the symbol below that,
each of those sections of data
completes one out of a total of 512 scan lines
that make up a completed image.
- To understand the rest of that diagram,
you have to understand how an old-fashioned
cathode-ray tube television worked.
And few enough people understood it
at the time when they were still in use.
Fewer understand it now. - And while I don't
understand cathode ray tubes, I tried an alternate method.
Using Audacity, a free audio program,
I selected .008 milliseconds of audio data
between each peak in the waveform
roughly corrosponding to the area
selected on the cover of the album.
I exported that data into a CSV file.
The data being exported is essentially
just number values based on the volume
of waveforms at different points
along that .008 millisecond section.
When you import the CSV into Excel,
you can use conditional formatting to assign
a different color value for different decibel levels.
Lower decibel samples translate into lighter grays
and higher decibels into darker grays and after doing
this for 12 hours and 512 times, we got this.
Now a circle isn't the most exciting thing in the world.
But it has a very important purpose.
If we look at the last image on the record's cover,
we'll see the calibration circle.
It's a major way point, if aliens manage
to decode a shape that matches this,
then they'll know that they're onto something.
There's no way we're going to do that
for the remaining 114 images.
But fortunately we live in a world
where code can help, and maybe aliens will too.
We reached out to Manuel Arturo Izquierdo,
an anthropologist who wrote his own code
in one night to make this process much, much faster.
- Basically the idea is take a thread of numbers
and fold them in a way you can convert
the thread into a kind of surface, yeah?
- Manuel's code takes these .008 millisecond symbols
and folds them as they would appear
in an old television set, rendering an image.
He uploaded the code to Github for others to use
and Emily Malec Brown, a developer on our product team,
helped get the code up and running on my computer.
To our astonishment, the images appeared
right before our eyes, proving
that even 40 years later and with
completely different technology,
the messages could still be properly decoded.
("Dark was the Night" by Blind Willie Johnson)
So with the help of an astronomer,
an artist, a coder, an anthropologist,
Microsoft Excel, and Python, we were
able to decode the golden record.
But let's not forget, we're not
the intended audience for this.
Is an extraterrestrial civilization
really going to have a shot at this?
For John that's really besides the point.
- Whatever happens to it in space,
whatever its unknown destiny is,
I think it represents a high water mark of our civilization
when we dreamed the biggest dreams, really.
And I hope it will serve as an example,
an inspiration for people to keep dreaming.
(acoustic guitar music)
- Hey everyone, thanks for watching our video.
Check out Vox.com's golden record video
where they have a selection of the images
and some of the audio and songs that played as well.
And don't forget to subscribe to our
Verge Science YouTube channel, thanks.