Adam Frank
speaker
594 appearances
1 recordings
1 series
first heard Dec 2024
last heard Dec 2024
Adam Frank’s voice in public audio — every appearance, attributed to the second.
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It wasn't like this thing immediately happened. But what we found with this hard steps paper, because the whole idea of the hard steps paper was It was one of these anthropic reasoning kinds of things where Brandon Carter said, oh, look, the intelligence doesn't show up on Earth until about, you know, almost close to when the end of the sun's lifetime.
And so he's like, well, there should be no reason why the sun's lifetime and the time for evolution to produce intelligence should be the same. Uh, and so therefore, and he goes through all this reasoning, anthropic reasoning, and, and, and he ends up with the idea that like, oh, it must be that the odds of getting intelligence are super low. And so that's the hard steps, right?
So there was a series of steps in evolution that were, you know, very, very hard. And because of that, you can calculate some probability distributions, um, and everybody loves a good probability distribution and they went a long way with this, but it
When you look at it, of course, the timescale for the sun's evolution and the timescale for evolution on life are coupled because life and the timescale for evolution of the earth is coupled is about the same timescale as the evolution is the sun. It's billions of years. The earth evolves over billions of years and life and the earth co-evolve.
That's what Brandon Carter didn't see is that actually evolution. The fate of the Earth and the fate of life are inextricably combined. And this is really important for astrobiology, too. Life doesn't happen on a planet. It happens to a planet. So this is something that David Grinspoon and Sarah Walker both say. And, you know, I agree with this. It's a really nice way of putting it.
So, you know, plate tectonics, the evolution of oxygen, of an oxygen atmosphere, which only happened because of life. These things, you know, these are things that are happening where life and the planet are sort of sloshing back and forth.
And so rather than to your point about do you need giant catastrophes, maybe not giant catastrophes, but what happens is as the Earth and life are evolving together, windows are opening up, evolutionary windows. Like, for example, life put oxygen into the atmosphere. When life invented this new form of photosynthesis about two and a half billion years ago,
that broke water apart to work, to do its chemical shenanigans. It broke water apart and pushed oxygen into the atmosphere. That's why there's oxygen in the atmosphere. It's only because of life. That opened up huge possibilities, new spaces for evolution to happen. But it also changed the chemistry of the planet forever.
So the introduction of oxygen photosynthesis changed the planet forever, and it opened up a bunch of windows for evolution that wouldn't have happened otherwise. Like, for example, you and I, we need that amount of oxygen. Big-brained creatures need an oxygen-rich atmosphere because oxygen is so potent for metabolism.
So you couldn't get intelligent creatures 100 million years after the planet formed.
Yeah, and we know this for a fact now. So there was this thing, Gaia theory, that was James Lovelock introduced in the 70s. And then Lynn Margulis, the biologist, Lynn Margulis together. So this Gaia theory was the idea that Planets pretty much take, or sorry, life takes over a planet.
Life hijacks a planet in a way that the sum total of life creates these feedbacks between the planet and the life such that it keeps the planet habitable. It's kind of a homeostasis, right? I can go out like right now outside, it's 100 degrees, right? And I go outside, but my internal temperature is going to be the same.
And I can go back to, you know, Rochester, New York in the winter, and it's going to be, you know, zero degrees, but my internal temperature is going to be the same. That's homeostasis. The idea of Gaia theory was that life, the biosphere, exerts this pressure on the planet or these feedbacks on the planet that even as other things are changing...
the planet will always stay in the right kinds of conditions for life. And now when this theory came out, it was very controversial. People were like, oh my God, you know, what are you smoking weed? You know, and like, there were all these guy and festivals with guy and dances. And so, you know, it became very popular in the new age community.
But Lovelock, actually, they were able to show that, no, this has nothing to do with the planet being conscious or anything. It was about these feedbacks that the biology, the biosphere can exert these feedbacks. And now that's become, whether or not, we're still unclear whether there are true Gaian feedbacks in the sense that the planet can really exert complete control.
But it is absolutely true that the biosphere is a major player in Earth's history. So the biosphere fights for homeostasis on Earth. So, okay, what I would say right now is I don't know if I can say that scientifically. I can certainly say that the biosphere does a huge amount of the regulation of the planetary state and over billions of years has strongly modified the evolution of the planet.
So whether or not a true guy in feedback would be exactly what you said, right? The biosphere is this somehow, and Sarah Walker and David Grinspoon and I actually did a paper on this about the idea of planetary intelligence or cognition across a planetary scale. And I think that actually is possible. It's not conscious, but there is a kind of cognitive activity going on.
The biosphere, in some sense, knows what is happening because of these feedbacks. So it's still unclear whether we have these full Gaian feedbacks, but we certainly have semi-Gaian feedbacks. If there's a perturbation on the planetary scale, temperature, you know, insulation, how much sunlight's coming in, the biosphere will start to have feedbacks that will damp that perturbation.
Temperature goes up, the biosphere starts doing something, temperature comes down.
Well, I'm glad you asked that question because that paper that David and Sarah and I wrote, what we were arguing was is that over the history of a planet, right, when life first forms, you know, 3.8 billion years ago, it's kind of thin on the ground, right? You've got the first species, you know, these are all microbes.
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