“Project Hi Maria“, the new film based on author Andy Weir’s book of the same name, is a wild romp through the cosmos.
The film explores many of the same areas of science as Weir’s previous work, from engineering and psychology to planetary and stellar science. But it also ventures into new territory: speculative biology. Ahead of the film’s release, we had the chance to speak with Weir about his approach to astrobiology and alien life in “Project Hail Mary.”
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In search of alien life
In “Project Hail Mary”, our sun is infected with an alien microbe called “astrophage”. These single-celled organisms feed on stars, converting their heat into neutrinos and then light, which they use to “tether” between solar systems. “It’s basically just mold that lives off stars,” Weir told Space.com in an interview. Which is pretty cool – except it’s slowly killing the stars it lives on.
This becomes the main catalyst for the film’s action: humanity must figure out a way to stop astrophages from eating the sun. And it provides an intervention for history to investigate the real field of astrobiology, or the study of how life might have evolved outside of Earth.
At this point in history, astrobiology is a fairly wide-open discipline. When we search for life elsewhere in the universe, we only have life on Earth as a point of comparison (so far). That means scientists tend to look for familiar properties: composed of cells, carbon-based, and a genetic code containing DNA or RNA. They also look for certain chemical signatures, such as methane, phosphine or water, in the atmosphere in distant (or nearby) planets.
As far as we know, these are not hard constraints; life outside earth may well exist outside these boundaries. But these exotic life forms can be difficult for humans to interact with, or even recognize as living things. “I didn’t want to try to invent several different types of life forms from scratch,” says Weir. “So I decided it was a panspermia event.”
A point of origin
Panspermia is the hypothesis that life may have been “seeded” throughout the cosmos after originating in a specific location. In real life, some scientists hypothesize that life on Earth may have run here on Martian meteorites, for example, or vice versa. In the universe of “Project Hail Mary”, life developed on a planet orbiting the star Rope Ceti around 11.9 light years away from our solar system. These single-celled ancestors of astrophages developed a method of hopping, hopping and hopping from star to star, allowing them to spread all the way to Earth and beyond.
Weir says this point of origin was very deliberate. “I chose Tau Ceti on purpose because it’s a very old star,” he said. Tau Ceti is believed to be over 9 billion years oldabout twice the age of our sun. This would give any potential life in the Tau Ceti system a huge evolutionary head start compared to our planet.
Also, astronomers have confirmed that there are at least two rocky planets orbiting the star. These planets, Tau Ceti e – renamed ‘Adrian’ in “Project Hail Mary” – and Tau Ceti bare more massive than Earth, and each orbits at a distance that would allow liquid water to exist.
Thought experiments in evolution
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Over the course of the film, Ryan Gosling’s character, biologist Ryland Grace, encounters three alien species: Astrophage, its natural predator taumeoba, and Rocky, a living alien from a planet whose star is also infected with Astrophage.
Astrophage’s unique biology allows it to metabolize thermal energy directly. Arguably, its most important function in the story is as the “MacGuffin” that powers Grace’s ship. By storing and releasing energy so efficiently, astrophages are the perfect fuel for an interstellar spacecraft. “If we had that in real life, we could really make an interstellar ship right now,” Weir said.
While astrophysics is the fantastic part of the story, its biology isn’t entirely unfounded—anything extremophilic microbes live in volcanic hot springs where temperatures regularly reach 80℃, while others can survive intense doses of radiation.
Taumeoba, another alien microbe, is trapped high in Adrian’s atmosphere. This parallels many species of bacteria and fungi on Earth make their home in the troposphere and sometimes influence the weather.
Rocky’s species is particularly exciting. Like humans, they have spoken languages, concepts of timekeeping and advanced engineering. But unlike us, they evolved in an environment with very little light, an atmosphere consisting mainly of ammonia, and especially no liquid water. This last feature might sound like it would disqualify Rocky’s planet from hosting life. But this is an actual possibility that real-world biologists have explored. ONE 2018 study in Nature Scientific Reports found that life could theoretically evolve without water under specific circumstances.
Research and writing about astrobiology helps scientists expand their imaginations and expand their horizons in the search for extraterrestrial life. Maybe one day we will find life outside our planet, just like the main characters in “Project Hail Mary” do.
But hopefully it won’t try to eat the sun.
“Project Hail Mary” lands in theaters across the US on March 20, 2026.
