As an astrophysicist, my world revolves around the wonders of space and the mysteries of the universe. This means I can be a tough critic of science fiction books and films that explore these topics.

But when I walked out of a recent preview screening of the film adaptation of Andy Weir’s 2021 science fiction novel Project Hail Mary, I had tears of joy in my eyes. The filmmakers had done justice not just to the original story, but also to the science at the heart of it.

The story revolves around Ryland Grace, played by Ryan Gosling, who awakes from a coma with no memory and no idea why he’s on a space ship 11.9 light years away from Earth. As his memories slowly start to return, the truth becomes clear. The Sun is dying, and he is our only saving grace.

So here are the science facts – as well as the science fiction – of the film, which is in cinemas in Australia and New Zealand from today.

In Project Hail Mary the Sun is dying due to an alien organism that has spread around our part of the Milky Way.

Firstly, could an organism spread from one solar system to another? According to some scientists, yes. It’s a theory called panspermia.

We have no hard evidence to prove it right now. But the theory isn’t completely wild. We know material from solar systems can be transported great distances – we ourselves have witnessed as least three interstellar visitors enter........

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