The science fiction film Project Hail Mary brilliantly uses authentic science to underscore the human drama and narrative tension of the story.

Based on the novel by Andy Weir, the story revolves around an effort to save the Earth – threatened by an alien organism that is consuming the Sun. By combining real science, compelling characters and a gripping narrative, the filmmakers have crafted a science fiction odyssey that might just inspire a whole new generation of scientists.

The story begins with the main protagonist, Ryland Grace (Ryan Gosling), waking from a coma in a sealed lab with no windows. Affected by amnesia, the novel describes how he nevertheless applies his knowledge of high-school physics to deduce that gravity in the lab is 50% greater than on the surface of the Earth. He concludes that he must either be in a constantly accelerating spaceship, or on the surface of another planet.

This opening scene perfectly illustrates a concept that Einstein described in 1907 as his “happiest thought”. Einstein realised that while a person is in perfect free-fall, they don’t directly experience the effects of gravity themselves. This is the state of weightlessness experienced by astronauts in orbit – in a perpetual state of free-fall about the Earth.

By the same token, Einstein realised that this inertial experience of acceleration is also perfectly equivalent to the force of gravity. As Grace discovers, there’s no way to distinguish the two. This principle of equivalence was the essential insight that Einstein needed to describe gravity as the effects of warped space-time in his general........

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