Buzz Aldrin, the second man to walk on the moon, is mighty impressed with Gravity. The famed astronaut has contributed a guest review of Alfonso Cuarón's sci-fi smash hit to The Hollywood Reporter. Above all else, he seems thrilled — or "extravagantly impressed" in Aldrin's own words — with the film's portrayal of zero gravity. "Going through the space station was done just the way that I've seen people do it in reality," he says.

"We were probably not as lighthearted as Clooney and Sandra Bullock," Aldrin says, referring to bits of humor that came during some of the film's most distressing scenes. "We didn't tell too many jokes when people were in some position of jeopardy outside the spacecraft, but I think that's the humanity coming through in the characters," he says. But Gravity isn't perfect: like Neil deGrasse Tyson, Aldrin points out some flaws with Cuarón's vision — albeit extremely minor ones. "There weren't enough clouds, and maybe there was too precise a delineation from space," he says.

Aldrin and Tyson disagree in one key area, though. The noted astrophysicist seems mystified (even disappointed) that "we enjoy a sci-fi film set in make-believe space more than we enjoy actual people set in real space," but Aldrin has a very different take. "We're in a very precarious position of losing all the advancements we've made in space that we did 40 years ago, 50 years ago," he says. According to Aldrin, Gravity and its $55.6 million opening "couldn't have come at a better time to really stimulate the public."