Project Hail Mary Author Andy Weir Calls Out Interstellar’s Biggest Scientific Flaw

So, 'Project Hail Mary' is cleaning up at the box office right now, and it's not just the biggest sci-fi movie out there—it's basically dominated all of 2024 so far. Critics are into it, audiences seem happy, and if you like space dramas that take their science seriously (or at least pretend to), this one's probably already on your radar.

An Ordinary Guy Tackling a Not-So-Ordinary Sun Problem

The movie puts Ryan Gosling in the shoes of Ryland Grace—a former microbiologist now teaching middle school science—who gets tapped for a mission when Earth's sun starts acting up, threatening the entire planet. It's not your usual chosen-one space hero setup, and that's sort of the point: the source novel is by Andy Weir, the same guy who turned 'The Martian' into a pop-science phenomenon (and let's be real, its 2015 movie adaptation with Matt Damon was pretty great too).

What makes Weir stand out is his obsession with getting the science right. He spends years on research because he wants his fiction to feel credible, which honestly makes his stories hit a bit harder if you're tired of hand-wavy movie science. On that note, Weir's approach has a lot in common with how Christopher Nolan tackled 'Interstellar'—another film where the fate of humanity means sending a fairly regular guy on a bizarre space mission.

Weir on 'Interstellar': Respect, But Also Some Side-Eye

Back in 2016, Andy Weir actually chimed in about 'Interstellar' during an interview that ran on Quora (now stored in the HuffPost archives for anyone who likes digging up old internet gold). He gave the movie props for its take on black holes and time dilation—the idea that time drags slower the closer you get to something massive. As Weir put it:

'The science about black holes is accurate - at least the part about time dilation. And the time travel stuff is internally consistent, if not actually possible.'

So far, so good. But Weir couldn't help poking holes in some of the movie's basic story logic. He put it pretty bluntly:

'I feel like some of the basic non-scientific plot conceits are questionable. I assure you, however bad the ecology of Earth gets, it'll always be easier to fix Earth than it will be to colonize another planet.'

Translation: no matter how terrible things get here, running off to another world is going to be a way bigger can of worms.

Similar Ideas, Different Takes

• 'Project Hail Mary': Ryland Grace is launched to Tau Ceti—it's one of the few stars unaffected by whatever's draining the sun. If he can figure out why, there's a shot to reverse Earth's slow-motion apocalypse.
• 'Interstellar': Earth can't grow crops anymore. Matthew McConaughey's Cooper gets roped into a mission through a wormhole to scout habitable planets. Instead of fixing Earth, their plan is to start fresh somewhere else.

In both movies, regular people sign up for cosmic-scale problems, but the core motivation is different: 'Hail Mary' is about stopping a disaster at home, while 'Interstellar' is more about cutting humanity's losses and finding a plan B among the stars.

But How Much 'Science' Is Sci-Fi, Really?

'Interstellar' went to some lengths to get its physics right—Nobel Prize physicist Kip Thorne was a producer and science advisor. He’s still answering questions about the movie, and in 2024, he told Neil deGrasse Tyson on StarTalk that there actually isn't scientific evidence ruling out a super-blight that wipes out everything we try to grow. As Thorne explained:

'According to the biologists that I discussed this with, they didn't know of anything that would prevent the development of a very vicious generalized blight. So that's what occurs in this movie. And it's something that biologists have never seen, but they cannot rule it out.'

Jonathan Nolan—the other half of the Nolan-writing team—wanted the blight to be catastrophic enough that ditching Earth sounded plausible, even if it's a stretch. Whether that works for you probably depends on your tolerance for doomsday plot devices.

Pick Your Favorite Contrivance

Let's be honest. All sci-fi needs to fudge reality somewhere, or else we'd be watching documentaries. 'Project Hail Mary' has its own made-up science in the form of "astrophage," an alien organism that literally eats starlight, which is why the sun (and others) are running out of juice. If you're cool with super-bacteria or energy parasites, you'll probably enjoy both films for what they are: big, ambitious space adventures trying to be as 'real' as blockbusters can allow.

'Project Hail Mary' Main Cast

• Ryan Gosling as Ryland Grace