Ryan Gosling Faces Aliens in Project Hail Mary

In the sci-fi book and now movie Project Hail Mary, astronaut Ryland Grace, played by Ryan Gosling, encounters three different alien lifeforms in the vicinity of Earth. He joins forces with one of them, from the star 40 Eridani, to try to stop another, an alien microbe from Tau Ceti, that is eating stars - including our sun. The third lifeform saves the day.

Aliens have long been a common trope in science fiction, but for audiences not steeped in Star Trek and Star Wars or who may be skeptical that UFOs are alien spacecraft, this premise may seem far-fetched.

So we asked UC Berkeley astronomer Gibor Basri, who has conducted research on distant planets, how likely it is that life exists around two stars a relatively short distance from Earth, with one being an advanced technocivilization.

A long-time science fiction buff who liked the book and movie, Basri said one-celled life in the galaxy is not unlikely at all. If you make optimistic assumptions about the conditions required for simple life to arise, there may be hundreds of billions of habitable planets and moons in our galaxy where it could happen. In a recent perspective piece in the journal Nature Astronomy, Basri reviewed what's known about the stars and planets with stable environments conducive to the origin of life - those in so-called Goldilocks zones - and speculated about the chances we will encounter other life within the Milky Way galaxy.

Basri, who taught in the astronomy department for 35 years, is best known as the discoverer of the first confirmed brown dwarf - dim but massive objects that are bigger than a planet but just shy of the mass needed to ignite nuclear fusion and become a star. Today, astronomers think that these failed stars may be as common as planets in the galaxy.

His specialty is star formation and the magnetic fields of stars - he authored the 2021 textbook An Introduction to Stellar Magnetic Activity - so he has opinions about the premises behind the Project Hail Mary book, by Andy Weir, and the movie, directed by Phil Lord and Christopher Miller. According to the plot, a microbe dubbed Astrophage is sucking up the energy from our sun and dimming it, which is destined to turn Earth into a frozen, dead planet. Basri also was a principal investigator for the Kepler mission to discover exoplanets a decade ago.

Suffice it to say, he has had a lot of time to think about habitable planets and the necessary requirements for life to arise - at least, life as we currently know it.

Basri also was the campus's first vice chancellor for equity and inclusion, a post he held for eight years, until 2015. And he's a 2016 recipient of the Carl Sagan Prize for Science Popularization. Now a professor emeritus of astronomy, he and his wife split their time between Berkeley and a walled, medieval town in Tuscany. In his free time, he is catching up on his science fiction reading and exploring a fresh interest in the nature of time - as opposed to how we experience time - and its implications for consciousness.

Berkeley News sat down with Basri recently to talk about life in the galaxy and the portrayal of alien life on screen.

Spoiler alert! For those who have not seen the movie or read the book, Grace encounters an alien spaceship piloted by a lone survivor, a rock-like but sentient life form he calls Rocky, who is on the same mission: to reach Tau Ceti and discover why a destructive, one-celled form of life they call Astrophage is not consuming and dimming that star, as it is our sun and the star 40 Eridani. It turns out that in the star Tau Ceti, the Astrophage has a natural predator that keeps it in check, what they call Taumoeba - analogous to a one-celled amoeba.

UC Berkeley News: First things first. What did you think of the movie Project Hail Mary?

Gibor Basri: I liked it. I had never thought of the book as a comedy, really, but the movie version was light-hearted. A New York Times review said that it's too light-hearted, but at the end, I'm like, no, we need that now.

In the book and the movie, the plot is driven by the fact that alien Astrophage are sucking energy from the sun. Then the main character encounters another alien, Rocky, and together they discover the alien microbe Taumoeba. How likely is this scenario?

Well, two of them were single-celled life forms, so I would say that's reasonably likely. If you make the most optimistic assumptions about how easy it is for life to evolve and you assume that single-celled life typically lasts for billions of years, then you get a very large number of planets that are populated with single-celled life in the galaxy - billions and billions.

Now, that's being optimistic and saying, well, life happened right away on Earth, so that means it's pretty likely. But you could also say that was a total fluke, so it's not likely. Until we find a second example of life, we can't know.

In your Nature Astronomy article, you wrote that ice-covered ocean planets or moons could be the most likely cradle of life, since the interior is protected and, if the planet has volcanic activity, there would be seafloor vents producing energy and minerals - an environment many think was the source of life on Earth.

Right, such an environment would have plenty of fuel for hydrogen chemistry. If life does arise that way, by far it will be the most common, because these types of planets and moons are everywhere. Close to us, Enceladus, a moon of Saturn, is the easiest opportunity to find it, since it has geysers venting water from its ocean underneath ice. If we find a second example of life on Enceladus or Europa, an ice-covered moon of Jupiter, then I think we're all going to say, oh yeah, it's billions and billions.

So single-celled life could be common. What about encountering another intelligent, technologically advanced civilization?

As I noted in my perspective piece, even with the most optimistic assumptions, technological civilizations would have to last hundreds of thousands of years to expect there to be very many around us in our Galaxy - like 10. If the average technological survival time is only a few thousand years, we could easily be the only civilization around currently. And it is much worse if you want one to be as close as in the movie because the Galaxy is so big. The average survival time would have to be millions of years.

Many of these 'guestimates' are based on the Drake Equation, proposed by the late astronomer Frank Drake. As you wrote, it's a way to estimate the number of planets in the galaxy with life, and also the number with the ability to communicate with us.

Right. But in my perspective piece, I wanted to think about life globally in space and time, because the universe is evolving. So the Drake Equation should become time-dependent in an astronomical sense. For example, the peak of star formation in the universe was about 10 billion years ago, meaning the chance of life originating would have peaked then. And star formation will peak again when the Andromeda Galaxy merges with the Milky Way in another 10 billion years or so.

I was amused that you wrote in your piece, 'Perhaps the Galactic Empire has already come and gone?'

Or it may be that if a technological civilization survived past a certain milestone, it would last forever. Some civilizations could be immortal.

I read that Rocky's home star, 40 Eridani, is a triple-star system dominated by a K dwarf star. In your piece, you wrote that stars like this are stable much longer than stars like our sun, and thus could be more likely to host long-lived civilizations.

The sun, a yellow dwarf, is not that stable - it's 4.5 billion years old, but in another 1 to 2 billion years it will have brightened enough that our oceans will boil. A star about three-quarters the mass of the sun will last for 20 billion years and it won't blast a planet with too much radiation from flares, like smaller stars do during their formation. That's the range of masses - K type or orange stars, which make up about 20% of all stars - that are better candidates for planets harboring life. There are several ongoing surveys of orange stars for exoplanets of the right sort.

What other aspects of the movie seemed implausible, from a physicist's point of view?

In both the book and the movie, the fundamental energy story was just magic. These little one-celled things that could store enormous amounts of energy and release it at will - the physics there was pure nonsense.

The other thing that bothered me was the amount of energy these Astrophages were eating. If you want to make the sun dim by a factor of two, that's a boatload of energy you've got to soak up. In my lectures, I often talk about the amount of energy the sun puts out. If you take all the energy that the human race produces every year, and you store that for 25,000 years, that is the equivalent of the amount of energy you would have to suck up to halve the sun's energy for one second. You'd need an implausible amount of Astrophages to do that. Stars are big beasts.

What struck you as realistic?

There was a lot of good science in the book, some of which made it over to the movie. I really enjoyed in the books the idea that the Rocky creatures hadn't figured relativity out and didn't know about radiation. That was very plausible to me, that you could have an intelligent civilization that didn't have certain kinds of knowledge that we have. And of course, it could have been vice versa as well.

Do you have any recommendations for sci-fi novels?

I still like the classics. Isaac Asimov. Arthur C. Clarke. Poul Anderson. Reading these authors was kind of how I got into astrophysics. I just loved space. And so now that I've done astrophysics for 40 years, I'm ready to come back.