The much-anticipated sci-fi film Project Hail Mary is out in theaters today. In it, light-eating alien microbes sap the sun’s energy, threatening life on Earth with extinction. To find a solution, an unlikely hero—a middle school teacher played by Ryan Gosling—is sent on a one-way mission to the star Tau Ceti and encounters an otherworldly sidekick nicknamed Rocky along the way.

Ryan Gosling wanted a friend.

And in space, orbiting the far-off star known as Tau Ceti, he encounters another being he names Rocky, a five-limbed creature that looks like a boulder which teams up with him to try to save both of t...