NASA's recent job posting for a planetary protection officer inspired a fourth-grader to become the next real-life guardian of Earth. 

Nine-year-old Jack Davis, a self-proclaimed "guardian of the galaxy" from New Jersey, wrote a letter to the space agency highlighting his many qualifications for the position, which is intended to prevent interplanetary contamination during space missions. 

"I may be nine but I think I would be a fit for the job. One of the reasons is my sister says I am an alien. Also, I have seen almost all the space movies and alien movies I can see," Davis wrote in the letter to NASA. [Best Space Movies in the Universe]

Davis also described his video game skills and ability to quickly learn new things. "I'm great at video games," he wrote. "I am young, so I can learn to think like an alien."

NASA responded to Davis' handwritten application, encouraging him to study hard and do well in school. 

"At NASA, we love to teach kids about space and inspire them to be the next generation of explorers," Jim Green, NASA's planetary science director, said in a statement accompanying the letter. "Think of it as a gravity assist — a boost that may positively and forever change a person's course in life, and our footprint in the universe."

In addition to the follow-up letter from Green, Davis received a phone call from Jonathan Rall, NASA's planetary research director. Rall congratulated Davis on his interest in working for NASA in the newly posted role. 

NASA's planetary protection officer is responsible for protecting Earth from extraterrestrial microbes contained in samples brought back from human and robotic space missions to the moon, asteroids or Mars, according to the statement. It is also intended to prevent Earth visits from contaminating other planets that might host life.