To find out more about the podcast go to What’s In A Kiss? 21 Million Years Of Evolution.
Below is a short summary and detailed review of this podcast written by FutureFactual:
NPR Shortwave Space Case: Neanderthal Kissing, Space Moss, and Thea Moon Origins
NPR’s Shortwave Space Case takes listeners from deep time to deep space, examining how kissing may trace back through primates to a common ancestor, studying how moss spores endure space conditions, and revisiting the giant impact theory for the Moon with fresh data about Thea. The discussion connects evolutionary biology with planetary formation, highlighting how researchers map traits across species, test plant survival in space, and interpret lunar samples to illuminate Earth’s water history.
Kissing Across Primate Lineages
The episode kicks off with researchers tracing the behavior of kissing, defined as non-aggressive mouth-to-mouth contact, through primates to a large-ape ancestor around 21 million years ago. Matilda Brindle from Oxford is cited for mapping this trait onto primate family trees, suggesting that both humans and Neanderthals likely shared this behavior. The discussion emphasizes how a seemingly romantic gesture can inform our understanding of ancient interactions and interbreeding among early hominins and Neanderthals, enriching the narrative of human evolution.
"Humans and Neanderthals were probably kissing each other" - Regina Barber
Space Moss: Survival in Extreme Environments
The conversation then shifts to space biology, focusing on bryophytes, mosses, and their spores. Bryologist Tomomichi Fujita explains why mosses are ideal models for space survival due to their ancient land-dwelling lineage. Before flight, moss spores were subjected to UV exposure and harsh conditions, with researchers noting remarkable resilience. Dartmouth cell biologist Magdalena Bezania comments on space-tested spores, noting that after nine months in space, more than 80% of the spores germinated upon return to Earth. The host explains that these spores could potentially endure roughly 15 years in space, implying that moss and similar bryophytes might contribute to oxygen production and soil formation on future space destinations. The study, published in Eye Science, signals potential for space agriculture and terraforming concepts, although it remains to be proven that the whole moss organism can grow under space radiation and limited light conditions.
"After 9 months in space, more than 80% of the spores germinated" - Magdalena Bezania
Thea and the Moon: Planetary Whodunit
The final science thread centers on Earth’s Moon formation. A new Science paper analyzes lunar samples and meteorites to infer Thea, the impactor that shattered into material forming the Moon and contributing to Earth’s early history. Purdue geochemist Kelsey Prizel frames the investigation as a planetary whodunit, exploring whether Thea formed close to the Sun and whether such a body could be the primary source of Earth's water. The interview discusses how inner solar system origins imply that water may have arrived via different mechanisms than if Thea had originated farther out where ices are more abundant. Lead author Timo Hopp from the Max Planck Institute explains that if Thea came from the inner solar system, water delivery to Earth likely occurred through other processes or later materials, and we would need samples from Venus or Mercury to resolve the origin question.
"This paper reads kind of like a planetary whodunit" - Kelsey Prizel
Open Questions and Future Research
The discussion closes by situating these findings within broader scientific debates. The Moon’s formation remains a dynamic area of study, with ongoing work to constrain Thea’s composition and origin. The team underscores that while Thea is unlikely to be the main water source for Earth, its inner-solar-system origin reshapes how scientists think about planetary formation and material exchange in the early solar system. The episode concludes with appreciation for the interplay between evolutionary biology and planetary science, acknowledging that breakthroughs in one field often hinge on new data from another.
"Thea could not have brought a lot of water to the Earth" - Timo Hopp