Hindustan Times ST (Mumbai) - Live
Wknd lifestyle Leap ears
What did the first moments after the Big Bang sound like? Did a certain dinosaur boom like a trombone? What was the loudest bang ever heard on Earth? A Book of Noises journeys back, and peers into the future: What are vibrations teaching scientists about how the brain works, and how to treat it? Take a tour of the astonishing sonic landscapes of our world
Listening deeply is so important, in a time when more sounds are being destroyed than are being created, says Caspar Henderson. “As we live through what many scientists describe as a mass-extinction event, more forms of life are dying out and the sounds they create are being lost with them.”
As a science journalist, a naturalist and an amateur musician, it was a combination of worry, wonder and curiosity that led him to take what he calls an “earwitness exploration of sound”.
After two-and-a-half years of exhaustive research, field work and compilation, A Book of Noises: Notes on the Auraculous was published, in 2023, by Granta and University of Chicago Press.
The book seeks to capture the ancient history of sound on Earth, and the astonishing breath of sonic landscapes in our world today. It touches upon sounds we haven’t heard but that have been pivotal to our existence — like the chimes that reverberated after the Big Bang. It tracks how new developments in the study of sound are aiding doctors, ecologists, seismologists, and glaciologists struggling to predict what may happen next in Antarctica.
Sound has played an integral role in health care since the invention of the stethoscope in the early 19th century, Henderson, 60, points out. Medical ultrasounds, where high-frequency sound waves are used to map internal organs, and echocardiograms for the heart, followed soon after. Experimental physicists are now studying how neurons vibrate when they pass electrochemical signals, to try to frame non-invasive treatments for neurological disorders.
“Our first glimpse of the greatest wonder and trial of our lives, parenthood, comes in the form of a fuzzy black and white smudge made from sound,” he writes.
Sound is integral, in many ways, to life, he adds. In the evolving field of soil ecoacoustics, biologists are using sensors attached to metal nails pushed into the ground as a sort of antennae that allows them to “listen” to the movements of worms, grubs, mites and other life forms. Plant roots make a noise as they push through the soil too, and by tracking these, soil acousticians hope to better understand, for instance, whether roots grow by day, by night, or only after the rain.
“There are numerous scientific and environmental reasons to study sound. For me, it enriches my sense of what it is to be alive,” Henderson says. Take a tour of the soundscapes he uncovers, from the very first bang that brought about the universe.
The first sounds
For the first 200,000 to 300,000 years after the Big Bang, the rapidly expanding universe reverberated as if filled with countless booming cosmic bells, writes Henderson. The universe in these first million years was so dense that it trapped light but allowed sound to pass through it at a much higher speed than it does through the atmosphere on Earth today.
These acoustic waves weren’t really chimes, he explains, but they did help shape the distribution of matter, with the wave peaks becoming foci for matter that would evolve, over millions of years more, into galaxies.
The sound of the Big Bang itself was first simulated in 2003 by John Cramer, then a researcher at the University of Washington. It likely would have been less of a bang and more of a low-frequency hum, he found. It would have been inaudible to human ears.
Data on the early wave peaks, meanwhile, is drawn from the findings of an international consortium of scientists working with the Dark Energy Spectroscopic Instrument (DESI), which sits in the Arizona desert and was built as part of an international effort (by countries including the US, UK, France, Mexico and Spain). The scientists have, over about five years, been studying the positions and velocities of millions of galaxies across 11 billion years of cosmic history.
The earliest chirps
Among the earliest notes intentionally sounded on Earth were the cries of the katydid, a kind of cricket, which rubbed a serrated vein on one wing against a plectrum on the other in an early example of stridulation.
This would have first occurred about 165 million years ago. The exact pitch – at 6,400 Hz, about a fifth above the highest note on the piano – can be deduced from the anatomy of remains preserved in amber.
In a recreation published in 2012, this stridulation sounds tinny and electronic: like a very small fire alarm running out of batteries, says Henderson. (These are among the first notes, or pitches, that palaeontologists can accurately reconstruct, and are not necessarily the earliest notes or songs of creatures on Earth.)
Ancient animal noises
The earliest animal sounds to have been accurately reconstructed are that of the Parasaurolophus, a plant-eating hadrosaur or duck-billed dinosaur, roughly the size of a bus, that lived in North America, about 75 million years ago.
The Parasaurolophus’s call was probably made through a hollow bony tube on its head. In the 1990s, scientists at Sandia National Laboratories in New Mexico created a full-sized replica, and discovered that it made a “splendid” noise.
Pitched at about 30 Hz, or just below the bottom note of a piano, the timbre has been compared to that of a trombone, because of which the Parasaurolophus is also called the trombone dinosaur.
It turns out that large carnivorous dinosaurs such as the Tyrannosaurus rex, meanwhile, did not roar at all. Palaeontologists have concluded that they probably boomed, closed-mouthed, like a crocodile, at the lower end of human hearing and into the infrasonic range, with perhaps some groaning and hisses thrown in.
(The T-rex bellows in Jurassic Park? Those were created using a mix of sloweddown baby-elephant cries, the roar of a tiger, some whale song, an alligator hiss, and the growl and bark of the sound engineer’s pet dog.)