This Week in Science – The Kickass Science Podcast · Dr. Kirsten Sanford Science Media

When Do We Know Enough?

·1 hr 52 min·10 clips

Researchers found long-chain organic molecules on Mars, but can't rule out non-biological origins.

This Week in Science (TWIS) is a long-running science news podcast hosted by Dr. Kiki and Blair, broadcasting live on Wednesdays. Episode 1048, recorded February 18, 2026, opens with an extended discussion of the Winter Olympics, praising American athletes for competing with sportsmanship and compassion, celebrating the diversity of competitors—LGBTQ+ athletes, mothers, people with day jobs—and highlighting a female speed skater’s sharp response to a dismissive reporter asking whether two silvers felt like two lost golds. The episode’s central science discussion concerns new Mars research: a team from NASA Goddard led by Alexander Pavlov has reanalyzed Curiosity rover samples containing long-chain organic molecules and tested whether non-biological processes—meteoritic transport, atmospheric haze fallout, hydrothermal chemistry, serpentinization—can account for the observed molecular signature. The researchers conclude they cannot rule out a biological origin, and while they make no claim that life exists on Mars now or that life definitely existed in the past, they argue the evidence is consistent with ancient biological activity. Kiki and Blair discuss what ancient microbial life on Mars would mean for theories of panspermia, the implications of a Martian mass extinction coinciding with the loss of its magnetosphere and atmosphere, and the frustrating stasis created by the grounded Mars Sample Return mission, which would test cached Perseverance samples now sitting on the Martian surface. The episode also covers water distribution in the outer solar system, new environmental findings, clam spit chemistry with potential biomaterial applications, and animal stories including snake cognition research, zebra finch vocal learning, and frog thermal tolerance studies in warming environments. The broader theme of “when do we know enough” runs through the episode, exploring the epistemology of scientific certainty—how much evidence is required before a claim can be made, and the difference between can’t disprove and have proven. Tone is upbeat, conversational, and genuinely curious, suitable for a broad science-enthusiast audience.

As heard by us

A conversation about certainty that keeps circling back to regulation, profit, and the common good.

This Week in Science is at its best when it asks when enough is enough and lets that question spill into Olympics banter, the economics of making and selling to consumers, and the chemicals in everyday life. From there, Dr.

Read the full review in PlayNext →

Why you'd press play

You want a science show that treats certainty like a moving target.

Read the full recommendation in PlayNext →

Listen to the show on

Apple Podcasts Spotify

Play clips from this episode More from This Week in Science – The Kickass Science Podcast