Katherine de Kleer: Planets, Moons, Asteroids & Life in Our Solar System | Lex Fridman Podcast #184

The following is a conversation with Katherine DeKleer, a professor of planetary science and astronomy at Caltech. Her research is on the surface environments, atmospheres, and thermochemical histories of the planets and moons in our solar system. Quick mention of our sponsors: Fundrise, Blinkist, ExpressVPN, and Magic Spoon. Check them out in the description to support this podcast. As a side note, let me say that this conversation and a few others, quite big ones actually, that are coming up, were filmed in a studio where I was trying to outsource some of the work. Like all experiments, it was a learning experience for me. It had some positives and negatives. Ultimately, I decided to return back to doing it the way I was doing before, but hopefully with a team who can help me out and, uh, work with me long term. The point is, I will always keep challenging myself, trying stuff out, learning, growing, and hopefully improving over time. My goal is to surround myself with people who love what they do, are amazing at it, and are obsessed with doing the best work of their lives. To me, there's nothing more energizing and fun than that. In fact, I'm currently hiring a few folks to work with me on various small projects. If this is something of interest to you, go to lexfriedman.com/hiring. That's where I will always post opportunities for working with me. This is the Lex Fridman Podcast, and here is my conversation with Katherine DeKleer. Why is Pluto not a planet anymore? Does this upset you or, um, has justice finally been served?

(laughs) So I get asked this all the time. I think all- all planetary scientists get asked about Pluto, especially by kids who- we just love for Pluto to still be a planet. Um, but the- the reality is, um, when we first discovered Pluto, it was a- it was a unique object in the outer solar system and we thought, you know, we were adding a planet to the inventory of planets that we had. And then over time, it became clear that Pluto was not a unique large object in the outer solar system, that there were actually many of these. Um, and as we started discovering more and more of them, we realized that the concept of- of Pluto being a planet, um, didn't make sense, unless maybe we added all the rest of them as planets. So you know, you could have imagined actually a different direction that this could've gone where all the other objects that were discovered in that belt, or at least all the ones, let's say, above- above a certain size became planets instead of Pluto being dis- declassified. Um, but we- we're now aware of many objects out there in the outer solar system in what's called the Kuiper Belt that are of the same size, or in some cases, even larger than Pluto. Um, so the- the declassification was really just a realization that it was not in the same category as the other planets in the solar system, and we basically needed to refine our- our definition in such a way that took into account that there's this- this belt of debris out there in the outer solar system of things with a range of sizes. Um...