Unexplainable

The Sound Barrier #4: Listen to the universe

November 12, 2025

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  • Astronomer Wanda Diáz-Merced, who lost her sight, pioneered the use of sound (sonification) to perceive and make new discoveries in space, demonstrating that listening can augment or replace visual data in astronomy. 
  • Robert Wilson's accidental discovery of the Cosmic Microwave Background radiation, which sounded like static (hiss) in his antenna, provided the first direct evidence supporting the Big Bang theory. 
  • Sonification, the translation of data into sound, is a powerful tool that allows scientists to perceive patterns and details in complex, often invisible, astronomical data that might be missed through visual analysis alone, potentially leading to new scientific breakthroughs. 

Segments

Wanda Diaz-Merced’s Early Life
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(00:00:00)
  • Key Takeaway: Wanda Diaz-Merced’s childhood imagination, fueled by her sister’s illness, fostered an early connection to space themes.
  • Summary: Wanda Diaz-Merced grew up in Gurabo, Puerto Rico, facing challenges including her sister’s chronic illness and her own diabetes diagnosis at age 10. A childhood memory of seeing a meteor shower with her father, who explained the science behind the falling rocks, sparked her initial interest in space. Despite losing her sight in college, she initially felt trapped in her science studies due to GPA requirements.
Discovering Sound in Space
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(00:05:28)
  • Key Takeaway: A friend introduced Wanda to radio waves from a solar emission, transforming her perception of her impending blindness.
  • Summary: Astronomy club president Emilio introduced Wanda to radio waves from the sun using an antenna and headphones, which she initially found bothersome. This experience coincided with a powerful solar storm, and hearing the emission transformed her despair into beauty and possibility. This event showed her she could still pursue astronomy by listening to space instead of seeing it.
Science of Sound in Space
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(00:08:05)
  • Key Takeaway: Sound requires a medium like air to propagate, making space inherently silent, but non-audible waves can be converted to sound.
  • Summary: The episode explains that sound, as pressure waves, needs a medium like air or water to travel, which is why space is silent. However, electromagnetic waves like radio waves and microwaves can move through space and be shifted down into the human hearing range via electronic receivers. This process is what allowed Wanda to hear the solar burst and what enabled Robert Wilson’s discovery.
Robert Wilson’s Big Bang Discovery
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(00:11:18)
  • Key Takeaway: Robert Wilson and his partner accidentally detected the leftover radiation from the Big Bang as persistent static (hiss) in their antenna.
  • Summary: Robert Wilson, a Nobel laureate, was attempting to measure microwaves from outside the Milky Way when he encountered a persistent, booming signal that sounded like TV static. After ruling out local noise, nuclear tests, and even pigeon droppings inside the antenna, the signal was identified by others as the expected leftover radiation from the Big Bang. Wilson’s initial reaction to this monumental discovery was understated, though he later recognized its significance.
Introduction to Sonification
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(00:20:36)
  • Key Takeaway: Sonification translates data from non-audible forms (like X-rays or visible light) into sound to augment perception, similar to a Geiger counter.
  • Summary: Wanda began working on sonification at NASA to translate data from sources like meteors into sound, aiming to augment perception beyond the visual realm. Sonification is distinct from directly listening to shifted radio waves; it involves translating any data into an audible domain using assigned sounds. This technique proved effective in tests, where scientists performed as well or better using sound data compared to graphs alone when detecting black hole signatures.
Sonification of Cosmic Events
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(00:23:55)
  • Key Takeaway: Wanda used sonification of merging neutron stars to clearly hear tempo changes indicating system rotation dynamics.
  • Summary: Wanda used high-pitched timpani hits for a sonification of merging neutron stars, allowing her to clearly hear tempo changes in the energy output as the stars orbited. She also used sonification to identify a subtle, fast decrease in volume within a gamma ray burst, a feature previously unnoticed in the visual data. This discovery relates to the creation of elements essential for life, linking Wanda’s work to the universe’s fundamental building blocks.
Kim Arcand’s Multi-Wavelength Sonification
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(00:27:15)
  • Key Takeaway: Kim Arcand uses distinct musical instruments to sonify multi-wavelength data, such as combining visible, X-ray, and infrared light from the galactic center.
  • Summary: Kim Arcand, working with X-ray data from the Chandra Observatory, prioritizes listening methods because much astronomical data is inherently invisible to the human eye. She created a sonification of the galactic center using piano for infrared, violin for visible light, and glockenspiel for high-energy X-rays. Hearing the data over time, rather than viewing it all at once, allowed her to notice strong features she had previously overlooked in the static images.
Validity of Sensory Data
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(00:33:36)
  • Key Takeaway: No single sensory representation of reality, including visual images of space, is inherently more valid than another, such as sonification.
  • Summary: The famous red, green, and blue colors in the Pillars of Creation image are merely assigned representations of sulfur, hydrogen, oxygen, and nitrogen, not their true appearance. Sonification is considered a natural extension of data translation, holding equal validity to visual representations because it moves authentic data from one form to another. This approach opens astronomy to people with different sensory biases, transforming them from beneficiaries to agents of change.