David Kipping on how the search for alien life is gaining credibility

Astronomer David Kipping has built a career not just at the cutting edge of exoplanet research but also at the forefront of science communication. On his popular YouTube channel, Cool Worlds, Kipping takes viewers on in-depth explorations of subjects like planetary systems, interstellar travel, and the search for life beyond Earth.

I first met Kipping at the famous 2018 NASA technosignature meeting in Houston, where the space agency first indicated they would be open to funding work on intelligent life in the Universe. As we are both astrophysicists and science communicators, I wanted to discuss Kipping’s journey from a young stargazer to a Columbia professor, his work on life in the Universe, and the challenges of explaining science in the YouTube era. 

Childhood origins

Adam Frank: Let’s start at the beginning. Every scientist has an origin story. What first drew you into space and science?

David Kipping: Like many people in this field, I’ve been fascinated since I was a kid. I think I was five or six when my parents gave me this massive book with a black cover and pictures of the planets. It was like an atlas of the Solar System. I remember being mesmerized by Jupiter and its moons. I’d stare at the page and memorize the masses and radii, then rush outside with my little telescope to find Saturn or Jupiter.

It felt different from my love of Star Trek. That was fiction, but this was real. These worlds were actually out there, waiting to be seen. I used to lie in the yard and imagine the Enterprise beaming me up.

Frank: I did the same thing! It’s funny how often that fantasy shows up in scientists’ childhoods.

Kipping: Yeah, it was an escape but also an inspiration. Later, in high school, a fantastic teacher named Mr. Fox fed me books on physics — John Gribbin, Schrödinger’s Cat stories, even Mr. Tompkins in Wonderland. That got me into particle physics for a while. The idea that neutrinos were flying through me every second blew my mind.

Frank: Where did you grow up?

Kipping: In Warwickshire, UK. I ended up studying physics at Cambridge. At first, I thought I’d go into particle physics. But by the end of my degree, I felt that gigantic teams were necessary to make progress in that field, and I’d be a tiny cog in a giant machine.

In astronomy, though, the frontiers felt wide open. We had a single lecture on exoplanets — only a few dozen were known at the time. I remember thinking, “Wait, that’s the tip of the iceberg!” That moment grabbed me, and I applied for a PhD in exoplanets at University College London. That set the trajectory.

Why astrobiology and technosignatures?

Frank: A lot of your work now touches astrobiology and technosignatures — the search for signs of intelligent life. What drew you there?

Kipping: For me, it’s the natural endpoint. If you’re studying exoplanets, you’re not doing it just to know their rock composition. The ultimate question is: Does it have life? Could we communicate with it?

Frank: Did you worry about any kind of scorn from colleagues?

Kipping: For a long time, technosignatures did have a “giggle factor.” Scientists would focus on habitable zones but shy away from the life question. I always thought that was bizarre. Why obsess over Earth-like planets if you don’t care about life?

Frank: We were both at that amazing 2018 meeting. Do you feel like things have changed?

Kipping: Things have shifted. NASA used to effectively ban the word “SETI” in proposals. Now there are grants funding it. Private money from people like Yuri Milner has energized the field. Students are excited to take risks and write SETI papers. That’s new and encouraging.

But the field is still small and vulnerable. One flashy claim can dominate the conversation, and in the social media era, sensationalism is amplified. That worries me. One bad actor could undo years of careful progress.

The rarity of intelligence

Frank: You’ve become known for your Bayesian approaches to the question of life. At times, you’ve suggested intelligence may be rare. Can you talk about that?

Kipping: It frustrates me when colleagues say, “When we detect life…” That assumes the answer. As scientists, we need to stay agnostic. We don’t know yet.  That means we have to concede the possibility that we are alone. I’m not advocating for that view; I’m just trying to remain objective. People sometimes misinterpret that as me wanting us to be alone, or even link it to religion. But it’s nothing like that — it’s just intellectual honesty.

Frank: There’s precedent for that kind of humility in not knowing right?

Kipping: History gives us cautionary tales. Percival Lowell in the 19th century was convinced Mars had canals. He saw lines in his data and interpreted them through the lens of his era. We’re vulnerable to the same trap: projecting our technologies, like solar panels, onto alien civilizations.

Frank: What else do we need to be mindful of?

Kipping: The alien hypothesis is dangerously flexible — it can explain anything. That’s why we need extraordinary rigor. Carl Sagan said extraordinary claims require extraordinary evidence, but I’d add: The flexibility of the alien hypothesis makes it especially treacherous.

The Fermi paradox and extragalactic SETI

Frank: Let’s pivot to the Fermi paradox: If life is common, where is everybody?

Kipping: The key is to stick to ground truths. We haven’t detected technosignatures, but SETI has been woefully underfunded and has only scratched a tiny fraction of the sky. So we can’t conclude much yet.

The hard facts are that Earth shows no evidence of outside tampering — we evolved naturally — and the Universe doesn’t appear engineered at cosmic scales. That suggests limits on how far technology tends to go.

Frank: So what can we get from those observations?

Kipping: Conclusions within our own galaxy are messy. Stars mix, materials trade places, interstellar meteors cross paths. That’s why I think extragalactic SETI is a powerful approach. Other galaxies are independent experiments. If we find evidence there, it would be clean, unambiguous. The challenge, of course, is their faintness.

Science communication in the age of YouTube

Frank: Let’s talk about outreach. Your YouTube channel, Cool Worlds, is incredibly impressive. What got you into this?

Kipping: I didn’t grow up with Carl Sagan as a hero — I discovered him late. In the UK, we had figures like Patrick Moore, but they didn’t inspire me. What really struck me was YouTube. Ten years ago, there weren’t academics on the platform. There was Vsauce, Hank Green, and some others, but no researchers. I thought: what if I combined being a scientist with being a communicator? That was rare then. It’s more common now, but it’s still a balancing act.

Frank: And those videos you make are beautiful. They must take enormous time to produce.

Kipping: They do. Sometimes I wonder why I’m doing it. But I’ve found it makes me a better scientist. Preparing a video on relativity or interstellar travel forces me to revisit fundamentals with fresh eyes. That’s led to real research ideas.

Frank: How did you find your own voice, your own style?

Kipping: At first, I tried imitating other YouTubers, and it didn’t work. We stalled at a few thousand subscribers. Then I said, “Forget it, I’ll just do this my way.” Those videos took off. I realized authenticity is the key. If I open a science video by talking about Tolkien, it feels risky, but it’s also genuine. And when viewers feel that authenticity — when you make them feel something — it sticks. That’s how science communication works best.

Risks and rewards

Frank: But you’ve also talked about the risks.

Kipping: Right. Having a million subscribers means responsibility. If I critique a paper, people accuse me of punching down. Once, after I criticized an over-precise estimate of civilizations in the galaxy, I got threatening emails from a senior figure in the field. When you’re tenure-track, that feels like academic bullying. So you walk a fine line. Do you detach from academia, like some communicators, so you can speak freely? Or do you try to balance both, knowing that your words carry extra weight? I’m still figuring that out.

Frank: After all this, what keeps you going?

Kipping: It’s the impact. At a conference recently, a young woman told me she became a scientist partly because of my videos. That’s incredible. Knowing I’ve helped inspire the next generation makes it worthwhile.

Frank: So doing the videos takes you past just being a researcher.

Kipping: Yes. Science is a human endeavor — our fears, hopes, and passions shape it. If my work can show that humanity and ignite curiosity in someone else, then I’ve done something meaningful.