TED Talk “A History of the Universe in Sound”: Speech Summary, Text, & Analysis

March 31, 2023

8 min read

Honor Harger

In Honor Harger’s 3-minute TED talk, she discusses a topic that has captivated many: what does the universe sound like? By exploring the history of radio astronomy and the stories of accidental discoveries, Harger uncovers the fascinating sounds of our universe, from the sun to the distant stars and beyond.

TED Talk “A History of the Universe in Sound” Speech Summary

We analyzed Harger’s TED talk using the free, AI-powered communication coach, Yoodli. You can get started at http://www.yoodli.ai and view the speech here.

  • The story of understanding the universe is as much about listening as it is about looking.
  • Alexander Graham Bell and Thomas Watson inadvertently discovered that the sun emits radio waves.
  • Karl Jansky studied the sources of radio noise to try and optimize Bell’s telecommunications revolution.
  • Arno Penzias and Robert Wilson heard cosmic radiation left over from the Big Bang. This provides the first evidence that the universe was born at a precise moment 14.7 billion years ago.

TED Talk “A History of the Universe in Sound” Speech Text

Using AI, the Yoodli speech coach platform provides this TED talk, “A History of the Universe in Sound”:

"Space: we all know what it looks like. We’ve been surrounded by images of space our whole lives, from the speculative images of science fiction to the inspirational visions of artists to the increasingly beautiful pictures made possible by complex technologies. But whilst we have an overwhelmingly vivid visual understanding of space, we have no sense of what space sounds like.

And indeed, most people associate space with silence. But the story of how we came to understand the universe is just as much a story of listening as it is by looking. And yet despite this, hardly any of us have ever heard space. How many of you here could describe the sound of a single planet or star? Well in case you’ve ever wondered, this is what the Sun sounds like. (Static) (Crackling) (Static) (Crackling) This is the planet Jupiter. (Soft crackling) And this is the space probe Cassini pirouetting through the ice rings of Saturn. (Crackling) This is a a highly condensed clump of neutral matter, spinning in the distant universe. (Tapping)

So my artistic practice is all about listening to the weird and wonderful noises emitted by the magnificent celestial objects that make up our universe. And you may wonder, how do we know what these sounds are? How can we tell the difference between the sound of the Sun and the sound of a pulsar? Well the answer is the science of radio astronomy. Radio astronomers study radio waves from space using sensitive antennas and receivers, which give them precise information about what an astronomical object is and where it is in our night sky. And just like the signals that we send and receive here on Earth, we can convert these transmissions into sound using simple analog techniques. And therefore, it’s through listening that we’ve come to uncover some of the universe’s most important secrets — its scale, what it’s made of and even how old it is.

So today, I’m going to tell you a short story of the history of the universe through listening. It’s punctuated by three quick anecdotes, which show how accidental encounters with strange noises gave us some of the most important information we have about space. Now this story doesn’t start with vast telescopes or futuristic spacecraft, but a rather more humble technology — and in fact, the very medium which gave us the telecommunications revolution that we’re all part of today: the telephone.

It’s 1876, it’s in Boston, and this is Alexander Graham Bell who was working with Thomas Watson on the invention of the telephone. A key part of their technical set up was a half-mile long length of wire, which was thrown across the rooftops of several houses in Boston. The line carried the telephone signals that would later make Bell a household name. But like any long length of charged wire, it also inadvertently became an antenna. Thomas Watson spent hours listening to the strange crackles and hisses and chirps and whistles that his accidental antenna detected. Now you have to remember, this is 10 years before Heinrich Hertz proved the existence of radio waves — 15 years before Nikola Tesla’s four-tuned circuit — nearly 20 years before Marconi’s first broadcast. So Thomas Watson wasn’t listening to us. We didn’t have the technology to transmit.So what were these strange noises?

Watson was in fact listening to very low-frequency radio emissions caused by nature. Some of the crackles and pops were lightning, but the eerie whistles and curiously melodious chirps had a rather more exotic origin. Using the very first telephone, Watson was in fact dialed into the heavens. As he correctly guessed, some of these sounds were caused by activity on the surface of the sun. It was a solar wind interacting with our ionosphere that he was listening to — a phenomena which we can see at the extreme northern and southern latitudes of our planet as the aurora.

So whilst inventing the technology that would usher in the telecommunications revolution, Watson had discovered that the star at the center of our solar system emitted powerful radio waves. He had accidentally been the first person to tune in to them. Fast-forward 50 years, and Bell and Watson’s technology has completely transformed global communications. But going from slinging some wire across rooftops in Boston to laying thousands and thousands of miles of cable on the Atlantic Ocean seabed is no easy matter. And so before long, Bell were looking to new technologies to optimize their revolution. Radio could carry sound without wires. But the medium is lossy — it’s subject to a lot of noise and interference.

So Bell employed an engineer to study those noises, to try and find out where they came from, with a view towards building the perfect hardware codec, which would get rid of them so they could think about using radio for the purposes of telephony. Most of the noises that the engineer, Karl Jansky, investigated were fairly prosaic in origin. They turned out to be lightning or sources of electrical power. But there was one persistent noise that Jansky couldn’t identify, and it seemed to appear in his radio headset four minutes earlier each day. Now any astronomer will tell you, this is the telltale sign of something that doesn’t originate from Earth. Jansky had made a historic discovery, that celestial objects could emit radio waves as well as light waves. Fifty years on from Watson’s accidental encounter with the sun, Jansky’s careful listening ushered in a new age of space exploration: the radio astronomy age.

Over the next few years, astronomers connected up their antennas to loudspeakers and learned about our radio sky, about Jupiter and the sun, by listening. Let’s jump ahead again. It’s 1964, and we’re back at Bell Labs. And once again, two scientists have got a problem with noise. Arno Penzias and Robert Wilson were using the horn antenna at Bell’s Holmdel laboratory to study the Milky Way with extraordinary precision. They were really listening to the galaxy in high fidelity. There was a glitch in their soundtrack. A mysterious persistent noise was disrupting their research. It was in the microwave range, and it appeared to be coming from all directions simultaneously.

Now this didn’t make any sense, and like any reasonable engineer or scientist, they assumed that the problem must be the technology itself, it must be the dish. There were pigeons roosting in the dish. And so perhaps once they cleaned up the pigeon droppings, get the disk kind of operational again, normal operations would resume. But the noise didn’t disappear. The mysterious noise that Penzias and Wilson were listening to turned out to be the oldest and most significant sound that anyone had ever heard. It was cosmic radiation left over from the very birth of the universe. This was the first experimental evidence that the Big Bang existed and the universe was born at a precise moment some 14.7 billion years ago.

So our story ends at the beginning — the beginning of all things, the Big Bang. This is the noise that Penzias and Wilson heard — the oldest sound that you’re ever going to hear, the cosmic microwave background radiation left over from the Big Bang. (Fuzz) Thanks. (Applause)"

TED Talk “A History of the Universe in Sound” Speech Analysis

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Honor Harger’s Word Choice

Harger’s word choice analytics from her TED talk were insightful to say the least. We found out that she didn’t use a single filler word during the duration of her speech, which is impressive considering it’s natural to have around 4% of fillers. Harger’s talk also contained less than 1% of weak words and she avoided non-inclusive language altogether: another big win.

The word choice analytics of Honor Harger showed that she didn't use a single filler word during her entire TED talk.
The word choice analytics of Honor Harger showed that she didn’t use a single filler word during her entire TED talk.

Honor Harger’s Delivery

The delivery of Harger’s TED talk was also phenomenal. Her speaking pace was perfect at about 133 words per minute. It was relaxed, conversational and clear. Her body language was positive (including smiling and hand gestures) and she used a few natural pauses to help her audience digest her talk a bit easier.

The places that Yoodli flagged to be improved, however, were affected by the method in which the speech was delivered. So, although Yoodli targeted centering and eye contact as potential areas of improvement, this is more of a reflection of the recording. The recording switches angles a few times and doesn’t always feature Harger straight-on, so these analytics can be taken with a grain of salt.

Honor Harger’s delivery was also impressive, particularly her relaxed speaking pace.

The Bottom Line

You don’t need to be an excellent TED talk speaker like Harger to benefit from seeing your own speaking analytics. In fact, checking out your insights via Yoodli can help you become a better conversational speaker, too.


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