Will We Ever Find Alien Civilizations?

The Joy of Why

Steven Strogatz, Janna Levin and Quanta Magazine

Science, Life Sciences

4.9 • 577 Ratings

🗓️ 9 July 2026

⏱️ 54 minutes

🔗️ Recording | iTunes | RSS

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Summary

Does intelligent life exist elsewhere in the universe? The question has captivated us for centuries, but despite decades of searching it remains frustratingly unanswered. Every so often a curious signal appears — fossilized structures in a meteorite, say, or an unusual gas in an exoplanet’s atmosphere — and for a moment it seems possible that we are not alone before the excitement gives way to a more mundane explanation.

So what would it actually take to find life in the cosmos — and how would we know when we saw it?

David Kipping, an astronomer at Columbia University, has spent his career finding better ways to answer these questions. His approach is statistical: rather than chasing individual detections, he develops mathematical frameworks for reasoning about where habitable worlds are likely to exist and how confidently we can interpret the signals they produce. In this episode of The Joy of Why, Kipping joins co-host Janna Levin to discuss efforts to frame one of humanity’s oldest existential questions as a tractable scientific problem, why biosignatures have proved so difficult to interpret, and why he believes exomoons may be an overlooked place to search for life.

Transcript

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0:00.0	I'm Janelle Levin.
0:06.3	And I'm Steve Strogetz.
0:08.1	And this is The Joy of Why.
0:10.3	A podcast from Quantum Magazine, where we discuss some of the biggest unanswered questions in math and science today.
0:16.6	So, Steve, I really have a good topic today.
0:21.6	It's aliens.
0:22.6	First of all, have you ever seen a flying saucer?
0:25.6	Let's just have it out, Steve.
0:27.6	Okay, this is where I have to admit, no.
0:29.6	But I would like to talk to you about aliens.
0:31.6	Okay, that's really good, because this is serious.
0:33.6	I think scientists take very seriously the idea that there's life out there.
0:39.9	Have you ever pondered the question? Are we alone?
0:42.5	A little bit. Years and years ago, I read a book by Francis Crick, you know, better known for his work on structure of DNA.
0:49.8	But Crick wrote a book called Life Itself, and he was interested in the idea that life on this planet might have been seeded by a process that people were calling directed panspermia, that maybe life had been sent here.
1:02.4	Yeah.
1:02.8	But the thing that really sticks with me from Crick's book was a point that he made, which is about what's the probability of life starting on a given planet?
1:12.9	And he said, we really don't know.
1:15.2	Like, we just really don't know.
1:17.0	And if the number is sufficiently small, like astronomically improbable, it could be that we're
1:23.2	the only life in the universe.
1:24.8	That's not impossible.
	...

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