What We Said To Aliens

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1:24Welcome to The Rest is Science. This is Field Notes, sort of expedition diary, as it were, where Michael and I, we're going to trade on discoveries, on curiosities, on riddles or questions maybe that have tickled our minds. That's right. That's exactly right. I'm glad to be here, Hannah. So what are we going to explore today? Well, OK, I think given that both of us essentially in our respective houses are effectively living in small museums dedicated to science, small shrines, shall we say, dedicated to science. I thought we could start with the stuff that is very obviously in the background. And I noticed that you've got the Arecibo message up on your wall.

2:02Oh, yeah. Can we talk about that? Yeah, we certainly can. So you might be at home. This is my office. I'm going to move my desk so we can observe these two big posters. These are representations of the Arecibo message, which were made. I had these made for an episode of Mind Field. I think the best way to explain them is that they are messages that we humans sent to outer space for aliens to potentially find and read back in 1974. They were sent from the Puerto Rican Arecibo telescope, which is no longer in existence. and the messages are still not even close to where we shot them at. Even though they're traveling at light speed, they were shot at the M13 cluster of stars 25 ,000 light years away.

2:48So it's going to take basically 25 ,000 more years for them to reach that cluster. But if there's any intelligent life out there listening for radio waves, they'll get not this nice color picture. They'll get something more like this black and white one, which is actually, if you look closely, a series of ones and zeros. So it's binary. It's a pulse and then no pulse. It's pulse, pulse, pulse. It's just on and off. And there's exactly 1 ,679 pulses. Now, as a mathematician, what's special about that number? That is, I mean, just off the top of my head, and not because I know about the RSA message before, of course, I know that that is two prime numbers multiplied together.

3:30Oh, my gosh. This is the idea of Carl Sagan, right? Carl Sagan and Frank Drake. Yeah, Drake and Sagan worked on this as well as, let me tell you the names of everyone involved, Richard Isaacman, Linda May, and James C.J. Walker, along with Carl Sagan. They said, hey, guys, we could send a message with this telescope. We could just shoot some radio waves out somewhere. And, you know, what should it say? What should a message from Earth be? And that's what they came up with. So why did they pick something that was two prime numbers multiplied together? I mean, they're very clever sausages, these two.

4:07These two people, you would think there's something good going on. Well, it might be too clever by half, as they say. That's why I had these posters made. We gave the message, not as a poster, but as a series of on and offs, as a bunch of bits, to a whole bunch of groups of mathematicians, college students. And we just told them, crack the code, figure out what this is. actually I think we told them this message has been received by a telescope operated by SETI the search for extraterrestrial life is it a message and what does it say and none of them were able to figure it out this was for an episode of minefield the psychology show I did but being the product of two prime numbers means that 1679 is pretty special we also call it semi-prime if you're the product of two prime numbers.

5:00And when you notice that, you go, man, you know, the only number that goes into 1 ,679 are 23 and 73. Is that true? Yeah. Is that if you're the product of two prime numbers, you only have two factors? Yeah, it's absolutely true. Okay. So you might think, well, let me arrange these pulses into a grid that's 23 by 73. So if you do that with 23 columns and 73 rows, a picture emerges, a visual picture of squiggles and lines. One of them right there, shown here more easy to see in red, looks like a little stick figure drawing of a person, a very pixelated human body. If you, however, arrange these pulses as 73 columns and 23 rows, it makes no sense at all.

5:52And you would just throw it away. You'd say it's noise. I know. So you have to be – you have to not only recognize the semi-prime nature of 1679. You also have to arrange it properly. But once you do that, it looks really non-random. It looks like it has some meaning to it, okay? Now, it does have meaning, and the meaning is almost comical, the way they tried to use just 1679 pulses to say a lot about us. The white stuff at the top here is the same as what you see here in the binary representation. It's ones and zeros. And if you use the ones, if you imagine the ones are the information and the zeros are the background, you can color code it like this black one here, which is a black poster with a bunch of colored squares on it that have been color coded to differentiate all the information.

6:44I'm kind of describing this to people who are just listening. At the top, you've got what looks like a bunch of white confetti. And that's actually the numbers 1 to 10 in binary. but there's like not enough room up here. So they had to do two columns for all the numbers over seven. And so to make it clear that the two columned sections are their own number, the bottom row is like a bullet point. So that's why one is two dots. It's actually a bullet point, meaning, okay, here's one number, one. And then they've got another bullet point. Here's two. And then two is a blank spot. and then a one, a zero and then a one.

7:29So, okay, we're doing this like binary counting thing. So hang on. So, because I didn't know this about the binary bit at the top. I just was like, there's numbers. Okay, fine. I never looked into it that deeply. But okay, so thus far, even if you are lucky enough to be from the same planet that this message was sent, even if you have the same counting system, the same concept of prime numbers as these students did, even if you know what binary numbers are, you still also then have to decode this weird extra pattern that they put in where they punctuated each one of the numbers. That's right. You also need to understand the concept of a bullet point system.

8:08Now, personally, I think that if we got a message like this, we would all work on it together. Like everyone would come up with so many different ideas. I feel like we might figure it out or at least someone would, whether we all believe them or not, I don't know. But yeah, it's almost hilarious how hard it is to decode. This purple shape, okay, which follows next, which also, by the way, not only do you have to have the same number system and you have to be able to detect radio waves of this frequency and you have to find that it's semi-prime, you also need to read top to bottom and left to right.

8:43Except the binary numbers are actually written bottom to top above their bullet point. Now, Now, the purple represents the elements that life on Earth is made out of. So it's got the numbers 1, 6, 7, 8, and 15 all kind of crunched together. And those are the atomic numbers of hydrogen, carbon, nitrogen, oxygen, and phosphorus. Okay. So we don't tell you that these are atomic numbers or that these are elements or anything. It's just that you're supposed to think, what's important about 1, 6, 7, 8, and 15? Well, if you have chemistry on your alien planet, you might say, well, that's maybe they're made out of that stuff.

9:25I don't know. The green stuff are the nucleotides that are in our bodies, represented again by numbers representing the atomic numbers of the elements in each nucleotide. Then here, the blue squiggle is the shape of DNA. Sure. Sure it is. Kind of. It's the double helix. And the white line in the middle of them, it's not a line. It's a cluster of – it's two columns of white squares with some black spaces in between them. That's the binary representation of the number 4.3 billion, which is how many base pairs the human body has? No. Oh, no. It's how many we thought the human body had in 1974. It turns out it's more like 3.2 billion.

10:16So it's also got misinformation about the human body. Wow. There is something very cool about this, though. If we keep going down, you see here's a picture of what humans look like so that the aliens can go, wow, that's what their bodies are. They've got like four appendages and a little ball at the top of a torso. So and then over here, there's a big cluster of white squares, and that is a way to represent in binary the population of the earth in 1974, how many of these little creatures there are. And funny enough, in 1974, the number of people we believe to exist was almost exactly the same as the number of base pairs we thought were in the human body, 4.3 billion.

10:59Which are both now wrong. Yeah. So they're wrong. One was wrong all the time. One was only temporarily right. There are many more than 4.3 billion people now. The blue line is just a stack of squares interrupted by a horizontal line of white squares. The blue squares represent that we're talking about the height of the person and the binary number here is the height of a typical person. Okay. When you say person, though, are we talking man? I mean, this was 1970s. That physical height is five feet, nine inches is what's being represented, which is the height of, drumroll, an average man. Average American man, no less.

11:41It could be an average human man. I don't know in 1974 what the average global male height was. But, you know, I guess aliens will know what we told them. Now, you can't see the rest of the image because there's a big chest in the way. But underneath there's some yellow. I'm going to move it up. And the yellow represents our sun and all the planets in the solar system. And the third one is raised up a little bit higher because that's the one we live on. It has a special position. I'll pick it up and bring it closer so you can see. Yeah, yeah, yeah. so okay from left to right you've got the sun and each of the planets presumably the number of dots represents how big the planet is roughly that's right hannah so the gas giants are represented by more than one square i can't actually hold this high enough without hitting my ceiling.

12:43But we're almost done because then, oh my gosh. Well, hold on a second though, because hang on, you've got Pluto on there. There's a blob on the right, which is also now incorrect. Pluto no longer considered a planet. Yeah. So imagine if the aliens not only read in the same way that we did, understood the bullet point system, used binary, understood semi-primes, they also have to have the same astronomical definition of a planet that we have. because imagine if they saw these yellow dots, right? And they were like, well, maybe those are planets and they found our solar system and they looked at Pluto and said, yeah, but Pluto hasn't cleared its orbit.

13:22So clearly we're looking in the wrong solar system. We need one that has nine planets, not eight. And then finally at the bottom, there's a picture of the, it's supposed to be a picture of the Arecibo telescope, the device that sent this message. the m shape represents the fact that it's a concave structure then the the numbers at the very bottom i don't even know what they're supposed to represent let me see if i can figure that out can i tell you my two favorite things about the rcb message yeah based on what you've shown us so the thing is right frank drake uh carl sagan like these big dogs of space and communication with you know the sciences and so on these like really really really cool amazing people in history.

14:03And I love the idea that they're like, right, we're going to send this message out to aliens and it's going to include this representation of like hydrogen and carbon and like DNA and a flattened double helix and a representation of all the people on Earth. And then, you know, they probably said that in a meeting somewhere. And then this is what they came up with. And it's like, I mean, even as someone who understands all of those things, the great beauty of all of those scientific kind of, you know, entities of like humanity and the planet. You know, the 1970s pixelated graphics are just not really doing it for me.

14:38It's sort of, it's this great wonder and awe, and then this absolutely, completely rubbish image, like A for effort, F for execution. My other favourite thing about the Aresuva message, though, is that it just kind of rounds everything off, I think. As you mentioned, they were aiming this message. You can't broadcast it to the entirety of the universe because that would just take way too much energy. So they very deliberately aimed it at this like little cluster of stars on kind of a corner of the Milky Way. And as you said, it's like 20 odd thousand light years away. And so unfortunately, by the time that this message reaches that spot, 20, whatever, 21 ,000, 25 ,000 light years time, those stars will have moved.

15:22So we are essentially broadcasting this nonsense message that is impossible to decode. Even when you decode it properly, it's just a pile of pixelated junk to nothing. Oh no, wait. I never thought about that. So it's like shooting a moving target. You need to shoot ahead of it. Right, which they didn't do. Well, in 25 ,000 years, how far will that cluster have moved? surely at least some fringe stars will still be in range maybe maybe i think in general though neat idea terrible execution michael that's uh that's what i'm giving i think you're right in how you graded it it gets an a for effort um and it gets an f for execution but i think this is all about effort this is not for aliens this is for us it's an exercise in how do we describe ourselves at the most basic level to a completely different intelligent life form.

16:19And we can think this is poorly done, but, you know, that encourages us to try to do better. Oh my gosh, it's going to crush me. I'm going to put this back away. For completeness, I want to say that the very, the squares at the very bottom represent the dimensions of the Arecibo telescope. Okay, I'm going to put this back on the wall before it hurts somebody. There we go. From top to bottom, incomprehensible binary numbers. You've got incomprehensible atomic numbers. You've got nucleotides. Maybe that one's sort of all right. You've got a flattened double helix. You've got incorrect information about the number of molecules in the human body, incorrect population data, incorrect solar system information, and a telescope that doesn't exist.

17:03Hey! You're welcome, aliens. What about the reverse, though? I mean, because we have turned on telescopes to try and hear whether there were any messages coming back. And as of yet, we haven't found anything. No, we haven't. I played my part for a long time. I lent my computer's processing power to SETI using SETI at home, where they process all the radio and probably other light form information they receive from their telescopes to try to find patterns, messages sent like these, not from us, but from potentially extraterrestrials. and I remember distinctly living in New York and going, I want to use my computer's downtime for a purpose.

17:49And the two things I could do were SETI at home or mine Bitcoin. And I chose listening for aliens and I found none. How long ago was this that you made this choice between SETI? This would have been in like 2008, 2009. So there were still a lot of Bitcoins out there to be mined. That's what I'm saying. Yeah. Yeah. You could have been a squillionaire. And I think there are still a lot of aliens out there to be found, but they're harder to find than the Bitcoins were 12 years ago or more. Which actually was a bit of a surprise. I mean, there was some people who thought that once we turned on SETI, once we started listening, there would be a cacophony of sound.

18:29There would be, you know, countless other life forms out there who had sent out messages like the Arecibo message just waiting for us to tune in and hear. And there was nothing. Radio silence. Yeah, we seem to be very alone. And that raises the question of why? Like, if life is so likely to occur in a universe as large as ours, why do we have no evidence of any intelligent life but ourselves? In fact, no evidence of life of any kind, except Earth life. And do you have your favorite answer to that question? I can run through some of the classic ones that aren't my favorite. One is that there's some kind of great filter, that basically in our universe, when life becomes intelligent enough, it inevitably destroys itself.

19:21I mean, this whole question is called the Fermi paradox, right? So Fermi, who was actually a big part of the Manhattan Project in building the nuclear bomb, but he was like, there seems like so much opportunity for life to exist. And yet there's no observational evidence of it at all. How is it possible that those two things can coexist? And then Drake came up with this equation to try and quantify how many potential life forms there were. He kind of breaks it down piece by piece by piece by piece, but he has this final term in it, which is about the length of time that an intelligent civilization can last for before effectively taking itself out.

19:58I don't know whether I buy that one, but it certainly feels like it a bit these days, isn't it? Well, yeah, it seems like maybe once you've got nuclear weapons, which he was very concerned about, of course, of course, it's only a matter of time before a species eradicates itself. And so sure, intelligent life has formed all over the universe. It's just that they don't last very long to like overlap and meet each other because there's something they do wrong. They mishandle nuclear weapons or weapons of similar strength. They mishandle something about space exploration, about trying to harvest energy from their sun.

20:33Who knows? It could be that the universe is teeming with intelligent life, but it's more like we live in a zoo. They're all watching us, but they don't make themselves known. They enjoy watching to see how we get on on our own. Or maybe they have a prime directive. Don't interact. Don't say hello until they reach a certain level of technological sophistication. But then there's the other option, which is that actually, maybe we were just all really far away from each other, you know? Like, as demonstrated by the Arecibo message, we tried to send a message out to aliens, and we've managed to point it to what is effectively, you know, a model village in another country.

21:17It's like shining a torch rather than, like, broadcasting a message. and it's incredibly difficult to build technology that will successfully be received by other life forms. But, you know, ultimately, I think once it comes down to it, you are talking about something that is incredibly, incredibly unlikely, the chance of life itself, and you're sort of multiplying it by something that is incredibly, incredibly, incredibly large, right? The number of opportunities for life in the universe. So who knows? You could be anywhere between, you know, life nowhere, everywhere life everywhere or like a small handful i i think like in my heart right i think i would be very shocked if we were really alone the universe is old enough there's enough stars there's enough um planets around those stars at the right distance to have liquid water and there's been enough time for that for life that started there to become intelligent given all of that though, why is the sky so silent?

22:15Why is no one talking to us? Are they avoiding us? Are we gross? Does intelligent life inevitably destroy itself once it gets nuclear weapons or weapons of a suitable strength? Do they mismanage their growth to other star systems? And do they mismanage the way they get energy from, say, their own stars? Do you know what? I think there's a new theory. having looked at the Arecibo message again, I think I've got a new theory, which is that they're out there. They saw that message coming for us. And they were like, these guys are just absolutely bonkers. Let's stay the hell away. I think I strongly suspect that might be what was going on.

22:54Yeah. We're sending out like basically horror movies to outer space. I think, honestly, for me, for the last few years, I've just felt like more and more convinced that we are alone. That the universe is not old enough for intelligent, sentient, conscious life to be plentiful. I think that in a billion years, I think that when the universe is just full of little blue dwarf stars that have long lives, there'll be a better chance for life to grow. But I think that we are the ancients. I think we are the first or among the very first intelligent conscious creatures in the universe. Well, OK, we might be alone in the universe, but here on Earth, we are very much not alone because we have got some questions from our listeners, a little mailbag bit, which is going to come up in a moment after the break.

24:06well welcome back from the break uh i hope you're refueled and ready to go because we thought we would try something with field notes we thought that we would have sort of like a mailbag you know like a like an old school radio show mailbag where you can send us in things they can be objects they can be ideas they can be questions um and we can you know spend a little bit of time examining them so this week we've got a couple of questions that have come in that we're going to use for the purposes of our mailbag. The first one comes in from Tony, who asks, can an expert tell the difference between a natural diamond and a lab made diamond?

24:38And do they have different commercial value? You want to take that one? Well, gosh, I haven't prepared. But I would think that they could tell because a lab diamond would be or could be a lot more clean. Like a natural diamond is going to have more clarity issues. I mean, I know a little bit. So I have this ring, which I stole from my auntie, but it's a really beautiful diamond ring. And I know it to be real because every time that I get my nails manicured, you put your hand under a UV light and the ring, there are certain stones in it which basically fluoresce blue. And that is because inside that stone, when it was formed, you know, however many, probably millions of years ago, right?

25:28There was nitrogen in the air, an abundance of nitrogen, and a little nitrogen atom was included within the sort of the crystal structure of the diamond. And I think that that's right, you know, is that like when you grow them, when you grow diamonds in a lab, you've got this perfectly clean, excellent environment that there's like total purity. But when diamonds exist in reality, right, when they're sort of formed in reality, they are effectively a record of the atmospheric conditions under which they formed. And so you have all of these little inclusions, you have these little fault lines, etc.

26:03So lab-grown diamonds are basically way more perfect and therefore, I think, boring. Yeah, right, right, right. They're just carbon atoms in a diamond structure. You could put nitrogen in lab-grown diamonds, though. That's actually what happened when we made the diamond hourglass, which I have right over here. Oh, yeah? This is the hourglass we made that contains 200 carats of diamond. They're lab-grown diamonds. Sorry, 200 carats? 200 carats. A carat is, I think, a fifth of a gram of diamond. There we go. There it is. So this hourglass contains lab-grown diamonds, and they're kind of a green color.

26:46They're very sparkly. What is it like dust? Yeah, they're very small. But see, the sparkling is really, really overwhelming. If you bring this out into the sunlight, it is very cool. Oh. And that green color comes from nitrogen that gets trapped in them while they're made. And it costs quite a bit more to get that nitrogen removed so they become clear diamonds. And we didn't do that for the subscription box. but we are going to go ahead and make a version with crystal clear diamonds. But this runs for a minute and it's, yeah. A minute of diamond dust. A minute of diamond dust. And this whole thing costs like 10 bucks to make.

27:27I have, I mean, I have quite strong opinions on diamonds. I think, I think diamonds as, as jewelry, right? Like, especially like whopping great big diamond rings. I'm not into it, but maybe that's one for another episode. Shall I give you another question? Okay, James R asks, which scientific discovery of the last 25 years will have the most positive impact on humanity going forwards? Got a candidate? Yeah, I mean, my answer is pretty quick. I think it's going to be fusion. I think fusion that is, you know, portable and long lasting is going to be almost like a BCAD transition for our species.

28:08Energy will just no longer be a concern. People like you and I will tell our grandchildren, like, we used to have to plug things in and we used to have to, like, buy new batteries and fill our cars up with fuel and pay bills. And there were limits to what we could do when it came to big, large-scale projects like space exploration or, you know, running computers. They got too hot. We had to build wind farms and it was expensive. And now it's like there's no limit. But there's also, I mean, if we did manage to crack fusion, a lot of the big existential questions that we've really been troubling ourselves with for the last few decades, I mean, essentially they disappear overnight, right?

28:46Like desalination becomes really, really possible. Stripping salt out of water is something that we can do. It's just really energy expensive. Then there's no shortage of clean water across the entire Earth. uh also taking carbon out of the atmosphere like suddenly becomes something that we can do really really easily fusion has has no byproduct that you know it's it's like the opposite of nuclear fission the nuclear power stations that we have at the moment where the waste is like extremely toxic for for many many thousands of years after we've finished with it plus you are essentially sitting on effectively a fragile atomic bomb that you have to control very carefully.