It’s always bittersweet whenever an incredible book becomes a new film. However, Project Hail Mary’s undeniable success as a movie reignited the popularity of the book. With the fame comes more audience, more critics, more thoughts. Many people are wondering: in a story so grounded in scientific logic, how accurate is it?

In his books, Andy Weir has an incredible skill of using hardcore, scarily difficult science and turning it into obstacles and strategies for his characters. He develops characters and relationships with depth, humor, and witty dialogue; drawing out raw flaws (I’d rather stay on Earth, thank you very much!) and reflecting on human solitude. Grace wasn’t the only isolated, lonely-in-space Weir character; Mark Watney was stranded on Mars and became friends with potatoes! Science fiction as a genre tends to lead a “the world is ending and we’re all gonna die let’s panic now” theme, and Weir leans into that, creating high stakes intergalactic settings and action packed scenes that turn the book into a fast paced page turner. 

In this sense, the book is a jewel of science, nerdy problem solving, and impossibilities coming true. “It’s this reminder of what we’re capable of as human beings.” Says Ryan Gosling, a co-producer and main actor. Something like that can be difficult to capture in a film, but I think it is important to accept the film as an adaptation of the book instead of an exact copy. 

So, how accurate is the science? 

Saying “the science” is quite generic. Are we evaluating the logic of the science in our current world with our current technological/evolutionary development, or the science within the setting of the book (yes, it’s this one. 😊)? 

We could look at this through the example of astrophage; through which the idea of fighting the villain of time is embodied. The root “astro” (derived from Astrum) describes a star or celestial body. “Phage” as a latin root means to eat, or devour. In other words, astrophages are the “star eaters” feeding on the Sun, reducing its solar output and threatening an ice age dooming all living beings on Earth to mass extinction. Is this possible? 

The sun emits energy (at 1026 joules per second) via electromagnetic radiation, and it maintains an atmospheric temperature higher than 5 million degrees Fahrenheit. Astrophysicist Jacqueline McCleary comments on how the astrophages’ similarity to (terrestrial) microorganisms in their biological processes could be the inaccuracy. They both have mitochondria, a single cell (like some which are Eukaryotes), convert mass into energy (ATP), and are DNA and water based (much to Grace’s disappointment). This does raise a question, however. Can astrophage perform the same biological processes as microorganisms while doing what they can’t? 

Currently, no discovered microorganism can survive in this extreme environment, much less absorb sunlight. The closest we have got are the fungi found in radiation levels five times as high as average levels on Earth. They exhibit radiotropism (extremophilic behavior; they thrive towards that source); and scientists believe that they may absorb the gamma radiation, converting it into energy. This is similar to photosynthesis: the exchange of sunlight, water, and CO2 into oxygen and glucose (containing energy). In Project Hail Mary, the astrophage consumes stellar energy using neutrinos (neutral and extremely light subatomic particles known as “ghost particles”) and pair production so they can convert that energy directly into mass without much loss. In an interview, Weir explained that pair production is a direct conversion of electromagnetic energy into matter; and it occurs when a photon (think gamma rays) interacts with an atomic nucleus, consequently creating a particle-anti particle pair. In order to do this, the organism must maintain a specific temperature (96.415 degrees celsius) so its protons possess just enough kinetic energy to collide and produce pairs. The conversion method perfectly generates the energy needed to transfer heat into neutrinos via energy to mass conversion.

 However, neutrinos can slip past solid matter, any form of matter (including you) . Weir’s method of dealing this is making the organism’s membrane so dense the neutrinos can’t pass through it (he coined the term “super cross-sectionality”). In the context of the book, this “shield” was also used against interstellar radiation.

Astrophage created the Petrova line to act as a high efficiency transit corridor (a highway, practically) to move between Venus (breeding ground) and the Sun. Chad Orzel, a physicist at Union College, says “Microbes could make a sun-Venus round trip with the right amount of power, but the journey would demand different amounts of it in each direction. From the sun to Venus wouldn’t be that hard because there’s already a steady flux of [solar] particles going in that direction,” However, the return trip “would require a bit more effort” to counteract the solar wind. Weir’s logic here was using the neutrinos as a propellant (if the astrophage creates the neutrinos within the cell membranes, it could be possible). 

[closing]

“It exposes people to real scientific ideas who might not otherwise see it,” McCleary said. “It may still make new scientists.”