Are We Alone in the Milky Way? It’s More Likely Than We Thought, New Study Says

Are We Alone in the Milky Way? It’s More Likely Than We Thought, New Study Says

The Drake equation is a set of variables used to calculate the probability of other intelligent life in our galaxy, the Milky Way. Astronomers have used the equation for decades to estimate the chances that Earthlings are alone in this corner of the universe.

According to the equation, it is fairly likely that there is more intelligent life out there. But new research offers some revisions to Drake’s ideas that could drastically reduce the likelihood that we share the Milky Way with other complex life forms.

Robert Stern, a professor of earth sciences at the University of Texas at Dallas and one of the paper’s authors, spoke to the Texas Standard about how a planet’s geology can determine its biology.

This transcript has been lightly edited for clarity:

Texas Standard: You’ve concluded that a planet needs three major geological features to support intelligent life: continents, oceans, and long-term plate tectonics. Why are these important for complex life?

Robert Stern: Well, let’s be clear: it’s not complex life. Whales, for example, are very complex. They may be more intelligent than us, but they couldn’t possibly build a radio that could transmit, and they couldn’t possibly build a rocket. So we actually call them advanced communicative civilizations.

So, you know, we had to evolve from a very simple single-celled organism 4 billion years ago to something that was complex and could swim and had eyes and limbs that could be modified to crawl out of the ocean onto land, which we did about 400 million years ago. But then something happened and we started walking and we started looking up, and we started making tools with our hands.

Now, you know, whales and dolphins can’t really study the sky like a human can. And they can’t possibly make tools – they don’t have fingers; they have fins.

And the other thing is electricity. I mean, we can’t imagine life without electricity today. Controlling electricity is completely impossible in the ocean. So for that reason, you need an ocean as a nursery and actually through, you know, a fair amount of evolution, but you need a big place where things can crawl onto land and evolve and look up at the sky and build the things that we’ve built over the last few hundred years.

And what about plate tectonics? How does that fit into the picture?

Now plate tectonics is crucial. We take that for granted, because we have plate tectonics. So the outer part of the earth is divided into a series of plates that move independently towards each other, away from each other, right past each other. And that creates a flow of all sorts of things.

First, it causes mountain ranges to grow, because there are collisions and the mountains erode, turning them into soil and washing nutrients into the sea, and these nutrients fuel life.

And the other thing that happens is that plate tectonics is constantly creating new habitats. So these new habitats that plate tectonics is creating are what is causing the isolation and what we call the speciation of new genera. And that’s plate tectonics, you know, the opening and closing of the oceans, the building of mountain ranges, the breaking up of continents.

These things are much better at creating these isolated habitats than what the other tectonic regime that we see on Venus and Mars has, which is that there’s basically nothing moving. There’s no big movement of blocks… I mean, continents and oceans don’t mean anything if you don’t have an ocean, right?

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Do we know how many planets in the Milky Way fit this profile?

No. We don’t know how many planets there are in the Milky Way. So, we only started discovering planets – you know, what we call exoplanets – in the 1990s.

And it’s very, very hard work. Planets are trivial in size compared to the stars they orbit. There are so many things that have to go right for us to see these planets that there are almost certainly many, many more.

I wonder if this hypothesis is limited by the perception of humans. Could there be life in the Milky Way that exists in ways that we cannot perceive with our senses and technologies?

Exactly. You’ve put your finger on probably the most important criticism of our study, and it might be that, okay, science always fails the imagination test. And I think that’s because scientists are human.

So yeah, if there’s another way to evolve an advanced civilization, it would be nice to learn more about it. But just by working from scientific principles and thinking about what plate tectonics does and what the absence of plate tectonics does, and thinking about the importance of oceans and continents, we’ve come up with some reasonable estimates given our sad state of affairs of what’s actually out there around other stars.

I think the dominant narrative is: there are thousands and thousands of advanced civilizations, but they’ve all heard about us and want nothing to do with us.

I know that as a scientist it is your job to remain impartial. But if you could take that hat off for a moment, would you be disappointed as a curious human being with the results of this work?

Oh, not at all. I mean, first of all, I’ve been writing scientific papers for 42 years. I’ve never seen anything like the interest in this story. I’m grateful, and so is my co-author, for this remarkable outpouring.

Because we’ve developed a new approach – we call it biogeodynamics, and the idea is that organism evolution is a response that’s more controlled by the way the solid planet behaves than most people think. So, for example, Drake, he assumed that, okay, once you get life, any form of life, it’s going to evolve into an intelligent communicative civilization. And so we’ve focused on just that one variable, that part of life that evolves into intelligent life.

But I think my co-author said it best. And the way he said it was kind of humorous: he said the universe would be sorry if our civilization didn’t succeed.

And I thought that was hilarious. It’s like everybody says, we’re doomed – climate change, politics, the standard litany of woes. But it’s like, wait a minute. We’re pretty special, and we’re special for a reason.