Big mysteries explained through your senses

TED Radio Hour

This episode explores how our senses—especially hearing, sight, smell, and touch—can reveal hidden truths about the universe and ourselves.

Key takeaways

• The Big Bang was silent because there was no medium for sound in the initial moments of the universe.
• Sound waves formed in the young universe due to gravitational compression, creating a 'cosmic symphony' that scientists have translated into audible form.

Main topics

• Cosmic sound waves from the Big Bang
• The science of smell (chemosensation)

Notable quotes

The most obvious thing is this decrease in pitch, the drop in pitch.

Conclusion

Our senses are more than tools for navigation—they are gateways to understanding

Transcript preview

Speaker 7 (0:00) This is Ira Glass. On This American Life, we tell stories about when things change. Like for this guy, David, whose entire life took a sharp, unexpected, and very unpleasant turn. And it did take me a while to realize it's basically because the monkey pressed the button. That's right. Because the monkey pressed the button. Surprising stories every week, wherever you get your podcasts. Speaker 2 (0:23) This is the TED Radio Hour. Each week, groundbreaking TED Talks. Our job now is to dream big. Delivered at TED conferences. To bring about the future we want to see. Around the world. To understand who we are. From those talks, we bring you speakers and ideas that will surprise you. You Speaker 1 (0:44) just don't know what you're going to find. Speaker 2 (0:45) Challenge you. We Speaker 1 (0:46) truly have to ask ourselves, Speaker 7 (0:47) like, why is it noteworthy? And even Speaker 2 (0:49) change you. I literally feel like I'm a different person. Yes. Do you feel that way? Ideas worth spreading. From TED and NPR, I'm Manoush Zomorodi. Today on the show, how our senses can reveal things about ourselves and the world around us that might otherwise remain invisible. Starting with what we can hear. Roughly 13.8 billion years ago, the universe began. We call that moment the Big Bang. Except it didn't make a sound. Speaker 5 (1:29) The term Big Bang does suggest an explosion. It suggests a sound. But things are a little bit more subtle than that. Speaker 2 (1:38) This is Mark Whittle. He's a professor of astronomy at the University of Virginia. And the first thing that Mark wants us to understand is that the Big Bang wasn't an explosion per se, at least not like in the movies. It Speaker 5 (1:53) was really in a way the expansion not of something in a pre-existing space, but it was the expansion of space itself, carrying material with it. And so paradoxically, the Big Bang was probably in a way silent. Because everything's moving away from everything else. There are no pressure waves. Speaker 2 (2:14) Pressure waves. That's what sound is. Right now, as I speak, tiny molecules are moving through the air. But if there's nothing to move through, no air, gas, or water, then there is no sound. So the universe, in its first few moments, was silent. But then, as it expanded, Speaker 5 (2:35) things changed. In the young universe, You did actually have a gaseous atmosphere pervading everywhere. That was the nature of the young universe. It was hot, but there was a gas, and through the gas, sound waves can move. Speaker 2 (2:52) So the Big Bang itself may have been silent, but almost immediately afterwards, the universe got noisy. Speaker 5 (3:00) The acoustic era started almost immediately, basically, and extended for about 400,000 years. Speaker 2 (3:10) 400,000 years might seem like a long time, but compared with the nearly 14 billion year life of the universe, Mark says it's roughly the equivalent of its first day. And during this period, the acoustic era, certain areas of space had more matter than others. Gravity pulled gas towards those denser regions, compressing it, bouncing it back out, pulling it in again, over and over. Speaker 5 (3:39) What you have there is an approximately spherical sound wave being created by gravity pulling gas. into these slightly denser regions and away from the slightly less dense regions so you have this whole set of compressions and rarefactions. Speaker 2 (3:57) This created sound waves moving through the entire young universe. Of course, no one was around to hear them, and even if Speaker 8 (4:07) you somehow could have been there, your ears would have been useless. Speaker 5 (4:11) The frequencies of the waves that I'm talking about are one wave every 50,000 years. So, I mean, you wouldn't even live to see one wave pass you. Speaker 2 (4:21) But what if we translated those waves into something the human ear can perceive? What would the beginning of the universe sound like? What you're about to hear represents the first 400,000 years of the universe, compressed into about 10 seconds and raised roughly 50 octaves into the range of human hearing. Thanks to Mark Whittle, it's like we can hear the universe expanding. Speaker 5 (5:04) So the most obvious thing is this decrease in pitch, the drop in pitch. Speaker 2 (5:11) Mark says, imagine the young universe as an enormous musical instrument, almost like an organ. At first, only its smallest pipes had enough time to produce waves. But as the universe aged, larger and larger regions joined in, and larger pipes make deeper notes. Speaker 5 (5:31) The musical instrument, if you like, of the universe is beginning to wake up and it wakes up in sequence, starting with the smallest organ pipes and ending with the largest. Speaker 2 (5:46) Our senses are how we make contact with the world around us. We use them to navigate everyday life. But they can also help us understand things that seem almost impossible to comprehend. So on the show today, a journey through the senses. What we can hear, see, feel, and smell. From an artist translating modern day challenges into physical art experiences. to a chemosensory researcher exploring the science of smell, and using sound to understand the expansion of the universe. Which brings us back to cosmologist Mark Whittle. Mark has been obsessed with astronomy since he was a child growing up in England. Speaker 5 (6:31) I was lucky in being a sort of 10-year-old in the mid-60s when... A lot happened in astronomy. And I also happened to be living in Cambridge in England. And some of what was going on was happening there. So discovery of pulsars, these sort of rotating neutron stars, discovery of quasars. So these were huge black holes, you know, far across the universe. And then, of course, you know, the famous discovery of the microwave background, the fireball. of the big bang and they all happened to roughly the same time i Speaker 3 (7:11) had Speaker 5 (7:11) a little box that i put you know articles that i'd cut out of the newspaper and Speaker 8 (7:16) a Speaker 5 (7:16) little paraphernalia your Speaker 8 (7:17) own little google that's yeah yes way Speaker 5 (7:20) predates anything like that but that was my little way of doing it and it fascinated me and i don't think i've ever looked back Speaker 8 (7:28) Can we just lay some groundwork? The Big Bang has really become one of your specialties, explaining and talking about that. But when I was a kid, it was presented as a theory of one of the things that may have happened to create everything around us. Speaker 5 (7:48) So certainly, I mean, of course, there's a famous TV show called The Big Bang Theory and the word theory is attached to it. Nowadays, I would say there's sort of, oh. maybe five or six just really key pieces of evidence which support the reality of a hot early phase in the universe's life roughly 14 billion years ago. And, you know, maybe the most obvious is the microwave background. It's essentially the glow coming to us from those early times across space. But when we look out, we don't see that light directly. the light waves got stretched as they crossed the expanding universe. And so they started out as light, leaving the young universe with wavelengths of about a millionth of a metre, that's a micron. And they arrived a thousand times longer. I'm sure it's a millimetre. And those are microwaves. So it is light that left the young universe, but it's microwaves that arrive. They've had a very long journey, you know, 14 billion years. And during that time, they've been stretched and they arrive, therefore, as microwaves. And that wavelength, of course, we attach the name microwave. It's the same, basically the same type of waves that are inside your microwave oven. Speaker 8 (9:03) Yeah. So I guess that brings me back to my question about the name, the Big Bang. I mean, call me literal, but I always assumed that meant there was a loud explosion. Speaker 5 (9:15) Yes. So let's just look at the coining of that term. the Big Bang, which was sort of 1950s, actually. And it goes to a series of radio programs broadcast on the BBC, where a prominent British cosmologist called Fred Hoyle was actually doing an excellent job communicating all these new discoveries. Speaker 7 (9:36) The implications of new galaxies forming are striking. Speaker 5 (9:40) He coined the term Big Bang to be slightly derisive, just saying, well, it's nothing more than a Big Bang, really. That name has stuck. Speaker 7 (9:50) There are actually many Big Bang cosmologies, and they all have the property that the universe is supposed to have started at a particular moment. Speaker 5 (9:58) But the creation of the universe in this so-called Big Bang was really rather different. It's involved, and it's difficult to get your head around this, but it's really not of an expansion into anything. It's an expansion of everything. Speaker 8 (10:14) God, it really messes with your head, doesn't it, Mark? Speaker 5 (10:16) Oh, yes. Speaker 8 (10:19) So how did you come up with this idea of translating all your measurements of these sound waves into music, something that we can Speaker 2 (10:27) listen to? Speaker 5 (10:29) So starting with the COBE mission, that's a NASA satellite in 1990, and then the WMAP satellite in 2003, the sensitivity of the microwave telescopes began to reveal these very slight patches on the microwave background. And what scientists do with the image of the microwave background, this full sky, this sphere of glowing with patchiness on it, is they do a wave analysis of it. And it produces a spectrum. And not only were these waves basically acoustic waves, but also there was a fundamental of harmonics. And that is exactly the signature of something like a musical instrument or a human voice. Speaker 8 (11:13) I mean, it brings new meaning to the phrase, feeling like you're in harmony with the universe, right? Speaker 5 (11:18) Yes, absolutely. Yes, both harmony, sort of emotionally and aesthetically, but also acoustically. Speaker 8 (11:26) Yeah. Speaker 5 (11:26) And so I just thought it was a wonderful way of communicating to the public what these new discoveries were, was to actually use sound as the bridge rather than light. Because everything, for the most part, as you said, is visual. The wonderful pictures from Hubble and other telescopes, they're all visual. And they're colour, and that triggers our sensitivity to colour. But our ears are not often used. And so I thought, well, here's an appropriate vehicle. Speaker 1 (11:55) Now here's a map of today's old universe, spanning four billion light years with us at the center, and it shows the positions of about 100,000 galaxies. Speaker 2 (12:05) Mark Whittle explains more from the TED stage. And Speaker 1 (12:08) if you perform a similar wave analysis, sure enough, there's the fundamental and harmonics showing up faintly in those web-like patterns. The sound waves have turned to stone, so to speak, and become fossilized. in the patterns of galaxies. But even more remarkable, I think, is that we think all of this cosmic structure, the sound waves and the galaxy patterns, had their ultimate cause with subatomic quantum vibrations during the universe's birth process, an incredibly short time of hyperexpansion that we call inflation. Now, this is a truly stunning proposition, that quantum oscillations smaller than atoms get amplified by cosmic expansion to make huge sound waves that then transform into an