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  • Hey, Vsauce. Michael here. This is Earth as seen from Saturn. That is us right there.

  • And if you look closely, ok, see this little protuberance? That's the Moon.

  • This image was taken by the Cassini spacecraft on July 19th, 2013 at 21:27

  • Coordinated Universal Time. The thing is, NASA gave the public advanced warning

  • of when it would be taken, which means that this image of Earth was the first

  • ever taken from space that some people on Earth were actually posing for. Our planet

  • looks so small, insignificant, fragile. I recently attended the premiere of Sky

  • 1's upcoming "You, Me and the Apocalypse" with some cool YouTubers and it got me

  • thinking. In the show, the characters find out that they're only 34 days left before

  • a comet smashes into Earth that's likely to end humanity. They all react in

  • different interesting ways, but what would I do if I found out that there

  • were only 34 days

  • of human history left? Ok, my first priority would be to get back to America to be

  • with my family.

  • But after that? I don't really have a bucket list. Except that is exactly what

  • I would want to spend my last few weeks doing. Making a list to put in a bucket

  • that I would then send far out into space away from Earth's impending

  • vaporization. The list would contain information about us, all Earthlings. So

  • that if libraries and monuments and YouTube videos were all destroyed, a

  • record would still exist somewhere

  • of what and who we were. Like a stone thrown into a lake, the ripples your life

  • causes last long after you vanish, the tree you planted is climbed by future

  • generations, the books you donated inform future readers. But what if it's not just

  • your stone that vanishes, but the entire pond? Perhaps it's arrogance or vanity, but

  • getting cosmic messages in a bottle out there, before the end, diversifies our

  • archive and gives a better chance for future alien visitors, or whatever is

  • left of humanity, to find out that we were once here,

  • to show what we learned. Maybe even to warn future life forms of what we did or what

  • we didn't prepare for. We have already sent some messages about humanity out

  • there, beyond Earth, and if Earth is completely destroyed, those messages will

  • be all that's left of us. What are they? Ok, first things first. How do you write

  • something for the future? I mean, the distant future. The message might not be

  • found for millions of years or billions. It might be discovered by an audience

  • that's completely different, not only in language, but in senses? What if

  • they can't see or hear or feel or taste or smell like we do, or at all.

  • What if their bodies destroy the very material we write the message on? What language

  • do you even write it in? Well, in general, math and physics, which are believed to be the

  • same everywhere in the universe, have been what we write outer space bound

  • messages in.

  • Like the Arecibo message, written by Frank Drake, Carl Sagan and others, which

  • was blasted towards the M13 star cluster in 1974. It's composed of a semi prime

  • number of binary digits conveying some info about us and it should reach the

  • center-ish of the M13 cluster in about 25,000 years, at which

  • point, if something intelligent lives there and detects it, they can respond

  • and their response will return to us another 25,000 years later. We won't be

  • around for that. But Earth has also been broadcasting its radio and TV signals

  • into space. Currently it's about 200 light-years in diameter. Compared to the

  • Milky Way, it's about this big. Aliens within that bubble could tune in and listen to

  • programs we sent out through our airwaves, but these signals thin out as the

  • bubble expands. Across very large distances they may be essentially

  • impossible to tune into.

  • Maybe a physical time capsule would be more permanent, but it can't be buried on

  • Earth if Earth is about to be ravaged. A time capsule in orbit might be smart,

  • like LAGEOS-1, a satellite put into orbit in 1976 that allows for very precise

  • laser measurements of positions on Earth, but also contains a plaque designed by Carl Sagan, upon

  • which is written the numbers 1 to 10 in the binary, and the arrangement of the Earth's continents 250 million years ago,

  • today and their estimated arrangement in 8.4 million years, which is how long we believe

  • the satellite's orbit will be stable. Drag caused by the thin atmosphere up where it orbits and

  • influences like solar activity

  • will eventually cause it to fall back down to Earth, but its plaque will serve as a

  • time capsule - a message from us today to whatever happens to be alive or

  • intelligent here on Earth

  • 8 million years in the future. To put that in perspective, the pyramids

  • were only built about 5,000 years ago. 8 million years ago, there weren't even

  • humans on the Earth. The latest common ancestor of humans and chimpanzees was around though.

  • 8 million years from today, when LAGEOS returns, what will intelligent life on

  • Earth look like? If Earth's surface is barren of life at that point, LAGEOS-1

  • will be alone. But what about satellites in geostationary orbits? These

  • orbits are far enough out that they're much safer from atmospheric drag and

  • could remain above Earth much much longer than satellites like LAGEOS.

  • These satellites are our pyramids. They're smaller than monuments built by past

  • civilizations, but impervious to anything that might go wrong on the less stable

  • surface of our planet. If alien archaeologists come by in a billion

  • years or so, these satellites may be what their alien encyclopedias use as the

  • picture for the humans article. So far we have erected about 450

  • of these geostationary monuments. When such a satellite wears down and

  • ceases to be operational, it takes a lot of energy to slow it down so it can move

  • out of the way and fall to Earth to burn up in the atmosphere. So instead, they're

  • usually pushed into what's known as a graveyard orbit.

  • A shell around the planet where they can be part without interfering with

  • important operational satellites. It's fitting that we call these graveyard

  • orbits because tombs are often the most stunning things we have from previous

  • civilizations. These graveyard orbits are tombs in a way. Not for kings, but for

  • machines. Junkyards that will out-exist the very societies and people they so

  • largely define. Luckily, a few contain more than just our craftsmanship. They

  • also contain a record, like EchoStar XVI, a communications satellite launched into

  • geostationary orbit in 2012. Aboard it is a silicon disc created by artist Trevor

  • Paglen, containing 100 images of Earth and Earthlings. Now, unlike LAGEOS,

  • EchoStar XVI will likely remain in orbit for billions of years,

  • safe from discord and change down here. But here's the thing. What if our entire

  • solar system is lost? Or what if life out there doesn't decide to ever visit our

  • system? Well, in that case, we have sent interstellar messages. At this moment, so

  • far, there are 11 distinct human made things on trajectories out of the

  • solar system into interstellar space. They're all related to five probes.

  • Pioneer 10, Pioneer 11, Voyager 1 and Voyager 2 and New Horizons, the thing

  • that recently made a Pluto flyby. These objects are our most distant hellos.

  • Over the next ten thousand, million, billion years, they'll pass close enough

  • to other star systems, maybe even planets, to possibly be discovered by other

  • intelligent life forms. We had the foresight to include special messages on

  • these probes. The Pioneer plaques are attached to Pioneer 10 and 11, which

  • launched in the early 1970's, were the first human-made objects to

  • ever be sent on a trajectory to not just leave Earth, but to leave the solar

  • system entirely. If discovered by other life out there, these plaques, designed by

  • Frank Drake and Carl Sagan, could be our first chance to say "hello,

  • we exist," or, depending on how long humanity lasts, our only chance to say

  • "Hello,

  • we existed. This is what we were." But will the plaques makes sense to aliens? Many

  • humans scientists have had trouble deciphering their meaning, but here's

  • what they say. At the bottom is a map of our solar system with a path showing the

  • Pioneer probe itself and where it came from. This element has been particularly

  • criticized for being human centric. I mean, an arrow? Who's to say aliens will know

  • that this depicts a path and not some structure in our solar system? Also, it's

  • an arrow. Arrows might convey this way only two civilizations that hunted or

  • developed pointy projectiles. Anyway. Up here, we define units. You can't tell

  • aliens about humans or Earth by using seconds, kilometres or light years,

  • because we made those measurements up. Instead, the plaque uses hyperfine

  • transitions to communicate distances and time. The hope is that curious

  • intelligent life forms who find this will understand that this is a hydrogen

  • atom - one proton, one electron. Hydrogen is the most abundant element in the

  • universe, so hopefully its properties will be a common point of understanding.

  • Now sometimes, if you've got enough hydrogen around, you can catch atoms in

  • the heap transitioning between particles with parallel spins and antiparallel

  • spins. Now, whenever this transition happens, electromagnetic radiation is

  • released with a period of about 2.7 nanoseconds and a wavelength of about

  • 21 centimetres. It's hoped that aliens equate this tick mark with these

  • two units of measurement. For example, the woman is said to be, in binary, eight of

  • these units tall. 21 centimetres times eight is a 168 centimetres.

  • You would think that putting the probe itself behind them for scale

  • would be enough to show our size, but having both might help solidify the

  • connection. This diagram is meant to show where we live. We are in the middle.

  • The direction and proportional length of the lines show where distant pulsars are.

  • A tick-mark near the ends of each line shows the third direction, behind or in

  • front of the plaque, that the line should go in. In binary, next to each line is the

  • period of each pulsar. Again, in the time units described above. If aliens

  • make this connection they could possibly match the periods with the correct

  • pulsars in real life,

  • triangulate our position and come say hello.

  • Also, since the period of a pulsar changes over time, they could use our

  • observed periods to date back how long ago this plaque was made. So that's how

  • the plaque works. It kind of feels like we're just sending out a bunch of

  • science homework to space, but how else can you find common ground with

  • something that might not resemble you in any way you could even imagine? Despite

  • heading out first,

  • the Pioneer plaques are not the first physical messages made by us to go

  • interstellar.

  • That title belongs to Voyager 1. Currently moving at 17 km/s, it is

  • the most far-out thing humans have ever made.

  • Literally. In about 40,000 years, both Voyagers will pass within less than

  • two light years of other stars. If aliens find them, or if future

  • humans find them, a golden record is attached to both that contains information about

  • humanity. The record is made of gold plated copper with an aluminum cover,

  • containing some uranium 238. Given its half-life, smart aliens could analyze it

  • to determine how long ago the record was made. On the record is the inscription to

  • the makers of music All Worlds All Times. The record contains 116 images, as well

  • as audio and video recordings of humans, animals, songs and greetings in fifty

  • five languages. Printed on the record are instructions for playback and info about

  • us. The hydrogen hyperfine transition unit definition and the Pulsar map,

  • included on the Pioneer plaques, but the record also comes with a stylus and

  • platter to play it. Instructions for using the stylus are on the record. This is a

  • picture of the stylus being used correctly and then in binary using the

  • transition units, the record tells the aliens that the stylus should go around

  • the record once every 3.6 seconds to play back correctly and in

  • total should take about one hour to do so. For the video portion, instructions

  • are given in a circle. The first video image is displayed, so they know they did

  • it right.

  • Also included on the record is a message from then-president of the United States,

  • Jimmy Carter. There's something vulnerable about the message. It's

  • delivered to an unknown recipient, like when someone in a horror movie asks

  • into the darkness "Is anyone there?

  • Hello?" This is what it says. "We cast this message into the cosmos. It is likely to survive

  • a billion years into the future, when our civilization is profoundly altered and

  • the surface of the Earth

  • may be vastly changed. Of the two hundred billion stars in the Milky Way galaxy,

  • some, perhaps many, may have inhabited planets and space faring civilizations.

  • If one such civilization intercepts Voyager and can understand these

  • recorded contents, here is our message. This is a present from a small, distant

  • world. A token of our sounds, our science, our images, our music, our thoughts and

  • our feelings. We are attempting to survive our time, so we may live into

  • yours. We hope someday, having solved the problems we face, to join a community of

  • galactic civilizations. This record represents our hope and our

  • determination and our goodwill in a vast and awesome universe." Are these messages

  • enough?

  • Should we send more? Well, why not send everything? We could, if we sent the

  • Library of Babel.

  • It's a website built by Jonathan Basile that currently offers everything that

  • has been or could be written.

  • Seriously. Divided into pages, it is built to produce and locate on demand any 3200

  • character combination of English letters and the comma, space and period. Basile

  • has organized it all into hexagon-shaped rooms, each with four walls of books

  • containing five shelves with 32 volumes of four hundred and ten pages each.

  • Everything's arranged in a pseudo-random fashion, so browsing the online library

  • feels like a treasure hunt. Here's how it works.

  • Each page is given a unique sequential page number in base 10. The text on each

  • page is encased inside this number.

  • An algorithm Basile created uses the page number as a seed to generate a

  • unique big number. That output is then converted into base 29 so that it can be

  • represented using every letter in the English alphabet as well as the comma,

  • the space and the period. This is what you see on the page. Basile has made

  • sure that the algorithm will produce every possible combination and the same

  • page number will create the same output every time.

  • Which means that what is on each page is already predetermined. So, in a way, every

  • page already exists. It only needs to be looked up.

  • And here is the really mind blowing thing. The contents of a page can be

  • converted to base 10, sent through the inverted algorithm and turned into the

  • exact page number they're found on. It's a truly eerie experience, because you can

  • find the permanent location for any 3200 character text. You can find in this

  • library the description of your birth, every possible description of your death,

  • every poem, every joke, every lie, anything that could be said

  • can be found on this site.

  • This thing blurs the line between invention and discovery. Did you really discover or invent

  • that thing if its description already existed? 10 to the 5,000 different

  • pages

  • are offered by the Library of Babel. In comparison, there are only 10 to the 80 atoms

  • in the observable universe. I searched for what I've just said and

  • sure enough in this hexagon, on this wall, this shelf and this volume on this page it's

  • there.

  • Hello.

  • But deep down, we feel like there's a difference between this program

  • permuting something unknowingly and a person actually meaning it, intending it,

  • saying it because they wanted to with agency. We use a finite number of symbols

  • to say things. For that reason, a library of every finite combination of those

  • symbols can be made, but just because it can be made

  • doesn't need it has been said. That is the power we have. Perhaps you and I were

  • born too late to explore the world and too early in history to explore the

  • stars, but we were born at just the right time, which is pretty much all times ever

  • to explore language. To explore what can be said. What should be said.

  • What should we send out to space. What that can't be said will you be the first to say?

  • And as always,

  • thanks for watching.

  • To watch the trailer of You, Me and the Apocalypse click right up there and