Podcast Summary: Unexplainable

Episode: The Sound Barrier #4 – Listen to the Universe

Date: November 12, 2025 | Host: Noam Hassenfeld (Vox)
Featured Guests: Wanda Díaz-Merced, Bob (Robert) Wilson, Kim Arcand

Episode Overview

This final installment in Unexplainable’s “The Sound Barrier” series explores how listening to the universe—rather than just looking at it—can dramatically expand our scientific understanding. The episode centers on the pioneering work of astronomer Wanda Díaz-Merced, who lost her sight but not her cosmic curiosity, and delves into “sonification,” the process of turning astronomical data into sound. Through rich storytelling and interviews, the episode digs into how sound has helped reveal the universe’s secrets, accessibility in science, and how different ways of sensing can revolutionize discovery.

Key Discussion Points and Insights

Wanda Díaz-Merced’s Journey: Listening as Science

• Personal History & Inspiration

  • Wanda grew up in a small Puerto Rican town. Her childhood was marked by her sister’s illness and her own diabetes diagnosis, which led to eventual vision loss.
  • Despite hardships:

    “I cannot change, and then I’m blind and I have a disability, but also I’m the only one that can work in my family.” – Wanda (04:40)

  • Wanda almost abandoned her dream of space science—until a friend introduced her to listening to space using a homemade antenna. The “ugly” noise she heard turned beautiful and meaningful when she learned it was a live solar emission.

    “At that very moment, I was dying and that death sentence began to lift up... For the first time, I felt happiness in my life.” – Wanda (06:58)

• Learning to Listen

  • Wanda discovered scientists had been listening to space for decades by shifting non-audible waves (like radio waves) into the range of human hearing.
  • Struggled academically due to lack of accessible reading tech, but persisted by learning from others in libraries.

The Role of Sound in Major Discoveries

• Bob Wilson and the Accidental Discovery of the Big Bang

  • Nobel Laureate Bob Wilson and his partner detected “static” in their radio antenna, which turned out to be the cosmic microwave background—the afterglow of the Big Bang.
  • The process involved ruling out earthly noise (including pigeon droppings!).

    “There was a pair of pigeons that lived in the antenna… So we put a little bait in there, caught the pigeons, but none of that made any difference.” – Bob (13:23)

  • Eventually, this faint sound was recognized as pivotal evidence for the Big Bang theory.
  • When realization finally hit:

    “We weren’t quite ready to say that that’s the only possibility.” – Bob (15:32)

• Sound in the Astronomer’s Toolkit

  • Sonification—translating any kind of astronomical data (imaging, X-rays, light curves) into sound—helps scientists perceive patterns and properties otherwise missed.
  • Wanda’s pioneering work in sonification at NASA, including detecting subtle signals (like neutron star mergers and gamma-ray bursts), led to new findings.

    “Audio will increase perception to things that are blind to the human eye.” – Wanda (22:16)

How Sonification Expands Science

• Accessibility & New Discoveries

  • Wanda’s tests showed astronomers using both sound and images did better at pattern recognition than either alone.
  • She used sonification to spot undiscovered resonances in gamma-ray burst data.

    “These resonances had not been identified by anyone. They had not been discovered before.” – Wanda (25:56)

• Kim Arcand and Multisensory Astronomy

  • Kim Arkand (NASA Chandra Observatory visualization scientist) described transforming X-ray data into soundscapes for images like the Pillars of Creation and the galactic center.
    • Example: Piano (infrared), plucky violin (Hubble), glockenspiel (Chandra X-rays) represented different energy ranges.

      “So you could hopefully hear that little crescendo at the end that is our supermassive black hole. So it’s really singing in X-ray light.” – Kim (30:08)

  • The act of listening to these data, rather than instantly seeing everything at once, fosters deeper, more deliberate analysis.

    “It changed how I thought of this data set… I never noticed. This is so strong there. How did I not notice that?” – Kim (30:53)

Rethinking Science: Beyond Vision

• Challenging Visual Dominance

  • Both Kim and Noam reflect on the bias that “seeing is believing,” reminding listeners that most astronomical discoveries are rooted in data invisible to human sight.
  • Even famous astro-images are color-mapped composites, not literal visual data.

• No Representation is Fully “Real”

  • The show argues convincingly—citing neuroscientist Dan Polley—that all perception is a construction of the brain and each sensory translation is equally valid in probing reality.

• Inclusion and Expansion

  • Sonification opens astronomy to those traditionally left out—especially people who are blind or low-vision.

    “Sonification of these types of objects has shown me that, like I might be welcomed working for NASA, working at an observatory.” – Kim (34:30)

  • Wanda cites feedback from her students:

    “I never thought I would be able to... It was by listening to the data that I realized that I can continue forward.” – Wanda (34:49)

The Future: Science Without Limits

• Institutes and Ambitions
  • Wanda is launching an Institute for Multi Sensory Science. Scientists aim to sonify 20,000 galaxies and probe for dark matter using sound.

    “If we bring more skills to science, we will have to delete the word limit. The emergence of science would be incredible.” – Wanda (36:43)

  • Accessibility is not just a moral issue but also a source of scientific enrichment.

Memorable Quotes & Moments (with Timestamps)

• The Transformative Power of Listening:
  • “At that very moment, I was dying and that death sentence began to lift up. You have no idea. For the first time, I felt happiness in my life.”
    — Wanda Díaz-Merced (06:58)
• Science as a Process of Elimination:
  • “There was a pair of pigeons that lived in the antenna… So we put a little bait in there, caught the pigeons, but none of that made any difference.”
    — Bob Wilson (13:23)
  • “There was poop in the antenna.”
    — Noam Hassenfeld (13:54)
• The Value of Diverse Methods:
  • “Listening to data like this… it forces you to slow down.”
    — Kim Arkand (31:17)
• Dismantling Limits:
  • “If we bring more skills to science, we will have to delete the word limit. The emergence of science would be incredible.”
    — Wanda Díaz-Merced (36:43)

Important Segment Timestamps

• Wanda’s Early Life and First Encounter with the Sun’s Sound: 01:53 – 07:41
• How Sound Travels (Physics of Sound and Space): 09:03 – 10:24
• History: The Accidental Discovery of the Big Bang (with Bob Wilson): 11:09 – 17:33
• Introduction to Sonification at NASA: 21:06 – 23:15
• Black Hole, Neutron Star, and Gamma Ray Burst Sonifications: 23:15 – 26:18
• Building Blocks of Life and Wanda’s Contributions: 26:18 – 27:14
• Kim Arkand on Visualizations & Sonification at Chandra: 27:14 – 32:35
• Broader Implications & Inclusion in Science: 32:35 – 36:43
• Wanda on the Future and Removing Limits: 36:43 – 37:24

Conclusion

This episode powerfully argues the case for rethinking how we perceive and study the universe. Through the stories of trailblazers like Wanda Díaz-Merced and scientists like Bob Wilson and Kim Arkand, listeners are invited to imagine a universe not limited by human senses—where listening becomes as vital as seeing, and where broadening participation in science leads to richer discoveries. The episode concludes with a call to dismantle barriers: in access, in imagination, and in the very senses we use to explore reality.