Carrion Luggage

Dualism

I have to admit, I was confused as hell until I saw this article, from Nautilus, made me realize that there are two of them.

    The Sean Carrolls Explain the Universe  
Why are we here? Is there life on other planets? The renowned scientists who share a name share their answers to life’s big questions.

Why are we here? Because we're here. -Rush

This is the tale of two Sean Carrolls. Nautilus brought the two scientists together for the fun reason that they share a name.

It's a pretty good reason, from an entertainment standpoint.

The Sean Carrolls bring their perspectives from physics and evolutionary biology to bear on timeless questions about the origin of life, the possibilities of life on other planets, the tension between science and religion, the fate of Earth, and how they first got enchanted by science as kids.

And this is the answer to the question you've been dying to ask me: who the hell are Sean Carroll? You might not have heard of them, but I read about physics and evolutionary biology for fun. The physicist/cosmologist one does videos that I've seen, which is why seeing the biologist one's name in print confused me.

The article does a brief bio of each of them, including plugs for their books. Then, they yap.

Physicist: So, what happened to make you do biology? It’s so messy and hard.

Hey, at least biologists study things on Earth. Physicists look at shit way far away, or way smaller than biologists do.

Biologist: Catching snakes and salamanders and frogs was something I did nearly every day. I thought “maybe I’ll be a herpetologist.” How did you stay on your path? How old were you when you knew you were interested?

Physicist: I was 10. I was reading books about black holes and the Big Bang. I was never a go-out-there-and-touch-things-in-nature kind of guy.

For contrast, I was both, and I didn't go into pure science. It was only later that I developed a strong aversion to the outdoors, after enough things out there tried to munch, poop, and/or slime on me.

Physicist: I remember very vividly my high school teacher asking us all what we wanted to do, and I said I wanted to be a theoretical astrophysicist. He was so aghast that he wrote the words “theoretical astrophysicist” on the board, just to show everyone how weird that was.

Ah, yes, this was back when high school teachers could spell "theoretical astrophysicist" without a spell-checker.

There follows a stretch where the two Carrolls discuss religion and its relationship to science. This is, to me, an interesting bit, but it doesn't lend itself well to quote-response here. It's almost inevitable that religion should come up in discussions like this, because of some of the fraught history that scientific inquiry has had with dogmatic belief structures.

Fortunately, the discussion stays civil, not just to each other, but to those readers who might hold different views.

Then they start talking about life: here on Earth and the possibility of its existence elsewhere, and, considering the number of times I've ranted on the topic, I figured one more won't hurt.

Physicist: If you do replay it from 5 billion years ago, where are the bottlenecks? Do you think the initial existence of life was difficult? Do you think that multicellular life was difficult?

Those are some of the base questions to ask when estimating the possibility of ET life, which is something people love to speculate about. I have my own ideas on the subject, but they could be wrong. Even Biologist Carroll could be wrong, but he at least has the background to make more informed guesses.

Biologist: My sense, and I think it’s shared by a pretty good part of the biological community, is that simple, unicellular, microbial life might be fairly prevalent in the universe.

Oh, but he's probably right, because that agrees with my preconceptions. (That was meant as humor.)

Physicist: That’s telling the story from a slightly parochial perspective. We know that Earth did it in the last 4 billion years of evolution. A lot of contingent events needed for it to happen that way. Are there completely different ways to get big animals with big brains?

Speaking of parochial, there is no direct correlation between brain size and smarts; that's a human perspective. I think he's obliquely asking, here, about the possibility of the kind of life that sends out deliberate EM signals and builds spaceships, the way humans do. As I've noted before, repeatedly and ad nauseam, the existence of life is no guarantee that a technologically capable species will eventually arise—though we know it can happen because, well, here we are, communicating via technology.

Biologist: If you gave me 100 planets with life, I would love that sample. I’m going to think large life like ours might be relatively scarce.

And that's the kind of data we need to answer that question with any higher degree of certainty. Right now, we only have one planet known to harbor life.

Physicist: Well, I do know enough to say that there’s a lot of planets out there. Back when you and I were graduate students, we had the solar system. Now we have thousands of exoplanet systems. I’m not at all surprised. I think there was some kind of weird PR thing where people were acting surprised that we saw all these planets. I was just expecting most stars to have planets around them.

If there was a "weird PR thing," it was probably aimed at the general public, who are only a few generations away from "stars are holes in the sky that let Heaven's light in," or whatever guesses their ancestors came up with.

Finding exoplanets, then, was no surprise to me, either—but it's one thing to say "other stars probably have planetary systems" and quite another to say "other stars definitely have planetary systems." And we can say the latter now, which is a testament to how clever we can be when we try.

Physicist: Many of them seem to be perfectly habitable by the little information we have.

And that's where you lose me, Sean. Sure, some of them are in the theoretical habitable zone of their respective stars, where stellar radiation is hot enough for liquid water and cold enough to not melt rocks. This does not mean that they are habitable. Mars and Venus are in the Sun's habitable zone. Europa and Enceladus (moons of the outer solar system) are not, and yet other factors contribute to them being possible Petri dishes.

I say this not to assert that I know more than either Carroll when it comes to science. I do not. I learn from them. It's a communication thing. You tell the average person that a planet is "habitable," and they jump to green trees and an atmosphere and cute, half-dressed, blue-skinned Zoe-Saldana-looking aliens (okay, maybe that last part's just me), but that's misleading.

Physicist: I think the simplest thing is that there’s lots of life in the universe, and it’s all monocellular, unicellular. We’re weird in that we’re not.

I tend to agree with that sentiment, for whatever it's worth. Occam's Razor and all that. Doesn't mean it's right.

Biologist: Visit the Earth anytime in the first 4 billion years or so and everything’s small. Everything’s essentially microbial. That was the state for the longest time. Animals and redwoods are weird. They’re the unusual things.

I'm a bit disappointed that Biologist Carroll didn't point out the role of eukaryotes, which, as far as I've been led to believe, make up all macroscopic life (and some very important microscopic life, like beer yeast) on our planet. That kind of organization, and I mean the word in its most literal sense, is what might eventually lead to rockets and radios and maybe antigravity or warp drives. Other readings have led me to the conclusion that this is probably an even less likely occurrence than that of life starting from chemicals in the first place.

But, you know. Whatever. It's possible to imagine lots of stuff, like simple life organizing into multicellular aliens and developing space travel. That doesn't mean it happens. Want to know the possible? Imagine the impossible.

I'm not sure, but I think it was Physicist Carroll who convinced me of that, many years ago. What we have to avoid is the trap of believing everything we think.

I'll wrap this up with something relevant to writing. Physicist had just spun a yarn, probably mostly true, from the dawn of modern science. Then:

Biologist: You told a story right there—that is the tool of engagement.

Physicist: It’s the single most effective one, if you had to pick one.

People respond to stories more than to dry facts. It's just part of who we are. The difficulty is that stories can fit almost any narrative, both factual and false. I lean to the belief that we have a responsibility to truth, even when we're writing fiction.

Well, except for jokes. I never let the facts get in the way of a joke.