Project Hail Mary's ending is wrapped up in science and some major surprises, but the movie also adds a scene not in the original book.

Ryan Gosling's "Project Hail Mary" contains a lot of scientific scenes and flashbacks. Here's a breakdown of the movie's most head-scratching moments.

Project Hail Mary ( PHM) is out now in theaters worldwide — and, whether you've watched Ryan Gosling's new sci-fi film yet or not, you might want to know how it ends. I don't know why you would if you ...