Podcast Summary: Could This Exoplanet Harbor Life?

Podcast: Short Wave (NPR)
Hosts: Emily Kwong, Regina Barber
Guest Host: Elsa Chang
Date: December 12, 2025
Episode Run Time: ~15 minutes

Episode Overview

This bi-weekly science news round-up dives into three intriguing topics: the search for life on an Earth-sized exoplanet (Trappist-1e), a new climate-centric theory behind the Black Death, and a grisly dive into how ants protect their colonies from disease. As always, the show balances deep scientific insight with wit, energy, and accessible explanations.

Key Topics & Insights

1. Exoplanets and the Search for Life

Starts at 04:11

• Exoplanets Primer:
  Regina kicks off with, “Astronomers have already discovered more than 6,000 exoplanets… some of them are more promising spots to look for life than others, like this exoplanet called Trappist-1e.” (04:18)

• What Makes Trappist-1e Special:

  • It’s rocky, Earth-sized, and “smack dab in the habitable zone” of its star, also called the Goldilocks Zone, meaning it receives just the right amount of light for possible liquid water (04:18).
  • Guest scientist Sukrit Ranjan elaborates:

    "It’s at this really interesting distance from its host star. It gets a little bit less light than Earth does, but way more than Mars does. If there’s life on it, we have the best chances of detecting it if it’s present on Trappist-1e." (04:42)

• Ingredients for Habitability:

  • The hosts recap the main requirements: not too hot, not too cold, plus the presence of an atmosphere (05:19).
  • Ranjan emphasizes:

    "It turns out to be really hard if it has an atmosphere, for it not to be habitable." (05:32)

• How Scientists Investigate:

  • Planets are analyzed as they pass in front of their star; the starlight passing through their atmosphere can be analyzed for biosignature molecules like CO₂ or methane (05:59).

• Study Results & Setbacks:

  • Emily summarizes:

    "Drumroll… sadly, no. A more in-depth investigation of Trappist-1e revealed no CO₂ and found that there may be no methane either. Oh, and… the majority of these Titan-like exoplanets, called exotitans, most likely lack an atmosphere entirely." (06:24)

  • Ranjan’s verdict:

    “The answer we came out to was, man, Exo Titans. Great idea. Not looking super good.” (06:44)

• Takeaway:

  • Elsa asks, “So is he saying habitable planets might actually be rarer than scientists previously thought?” (06:50)
  • Regina clarifies, “At least these kinds of habitable exoplanets… we really just need, like, better telescopes to get to the bottom of this.” (06:56)

2. Was the Black Death Triggered by Volcanoes?

Starts at 07:03

• Historical Context:

  • Emily sets the scene: “One of the most defining events of that time, the Black Death, which killed one third to one half of the population of Europe.” (07:10)
  • Elsa: “It was rats, wasn’t it? That’s what I always thought.” (07:24)
  • Regina corrects: “Close, Elsa. It was a bacterium… spread by fleas on rodents that hitched a ride from the shores of the Black Sea to what is now Italy in 1347.” (07:25)

• A New Climate Link:

  • Emily introduces new research:
    • Scholar Hannah Barker discovered a grain trade reopening in 1347, possibly explaining the rodent influx.
    • Regina: “This raised a question – why were Italian states worried about famine that year? Martin Bauch… thinks it might have to do with volcanoes that erupted a few years prior.” (07:58)
  • Bauch’s hypothesis: “There must have been a major volcanic eruption when sulfate is put into the higher strata of the atmosphere… then circling the globe for up to three years.” (08:11)

• Evidence:

  • Tree ring samples showed bad growth conditions pre-plague; ice cores showed high sulfate aerosols, both pointing to a volcanic event around 1341 (08:46).

• Summing It Up:

  • Elsa encapsulates:

    “Volcanic activity led to some sort of climate downturn, which led to crop failure, which led to grain imports coming in that brought all these rats carrying the bacteria to Italy. And then a bunch of people died.” (09:06)

  • Emily adds, “Now, this is just a hypothesis, of course, but it suggests that one of the biggest pandemics in human history could have been connected to the climate.” (09:23)

3. Sick Ants Call for Their Own Destruction

Starts at 09:32

• Discovery:

  • Regina introduces the “gory tale, but for the common good” — ants using chemical signals to ask nestmates to kill them if they’re infected, preventing colony-wide outbreaks (09:43).

• Mechanism:

  • Worker ants pay close attention to juvenile ants (pupae) in cocoons. Infected pupae emit a chemical signal.
  • Emily cites researcher Erica Dawson:

    “First the worker ants peel off the cocoon and then they bite holes in the pupae and then they spray formic acid. And this basically serves to disinfect the infected pupae because it kills off the fungus.” (10:11)

• Self-Sacrifice in Nature:

  • Regina: “While the acid kills off the fungus, it also kills the pupae. So in effect, the pupae is essentially calling for its own death, saying hey, I’m sick.” (10:49)
  • Elsa: “Kill me now before I get you sick too.” (10:59)
  • Emily: “Yes, that is the dramatic monologue of these infected ants, though there is a plot twist…” (11:02)
    • Queen pupae do not send the signal even when sick, and are more likely to survive infection on their own.
    • Regina: “Future queens just… they don’t signal when they’re sick.” (11:23)
    • Elsa: “They’re above the self-sacrifice.” (11:25)
    • Emily: “Yes they are. And also the infected future queens could fight off the infection on their own.” (11:25)

• Memorable exchange:

  • Elsa jokes: “True queen. Just like Emily Kwong and Regina Barber from NPR science podcast Short Wave.” (11:30)
  • Regina: “Elsa, thank you so much for coming to talk with us about science and calling us queens because we are news queens.” (11:38)

Notable Quotes & Memorable Moments

• “If there’s life on it, we have the best chances of detecting it if it’s present on Trappist-1e.” — Sukrit Ranjan, 04:42
• “Drumroll… sadly, no. A more in-depth investigation of Trappist-1e revealed no CO₂ and found that there may be no methane either.” — Emily Kwong, 06:24
• “Exo Titans. Great idea. Not looking super good.” — Sukrit Ranjan, 06:44
• “Volcanic activity led to some sort of climate downturn, which led to crop failure, which led to grain imports… and then a bunch of people died.” — Elsa Chang, 09:06
• “While the acid kills off the fungus, it also kills the pupae. So in effect, the pupae is essentially calling for its own death, saying hey, I’m sick.” — Regina Barber, 10:49
• “True queen. Just like Emily Kwong and Regina Barber...” — Elsa Chang, 11:30

Timestamps for Important Segments

• 04:11 – Segment begins: Trappist-1e, habitability, and atmospheric findings
• 06:44 – Ranjan’s verdict on exo Titans and planetary rarity
• 07:03 – Black Death and the climate connection
• 08:46 – Scientific evidence for historic volcanic activity
• 09:32 – Ants' self-sacrifice chemical signaling
• 10:49 – The biology and ethics of ant colony behavior
• 11:25 – The exceptional case of queen ants’ immunity

Tone and Style

Light, witty, and inviting — the hosts cultivate both scientific curiosity and friendly banter (“True queen. Just like Emily Kwong and Regina Barber…”). There’s a clear drive to demystify complex research for all listeners, with clarifying analogies and playful asides keeping things accessible and fun.

In short:
This episode offers a whirlwind tour through the latest astrobiology, history, and animal behavior research. Listeners walk away with fascinating new questions and memorable scientific tidbits in under fifteen minutes — in classic, irreverent Short Wave style.