The BEST episodes of NASA's Unexplained Files season 4
Every episode of NASA's Unexplained Files season 4, ranked from best to worst by thousands of votes from fans of the show. The best episodes of NASA's Unexplained Files season 4!
Strange flying objects have been caught on NASA's cameras and astronauts have reported seeing UFOs. Some of the odd shapes and lights can be identified; others remain a mystery. We'll reveal NASA footage and interview the astronauts and scientists.
#2 - Pluto's Stranger Things
Season 4 - Episode 1 - Aired 8/30/2016
Evidence of alien technology around a distant star; speculation about Pluto's surface; Apollo astronauts are at a loss of words to describe an object they encountered while they approached the moon. Science Channel has named this episode the first episode of season 4.
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#6 - Mystery of the Invisible Planet
Season 4 - Episode 7 - Aired 10/11/2016
A probe carrying a message to aliens malfunctions as it enters deep space. A NASA mission goes disastrously wrong when an imposter breaches Mission Control. Astronomers may have found an invisible planet around a distant star.
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#7 - Did Earth Have Two Moons?
Season 4 - Episode 6 - Aired 10/4/2016
A discovery suggests the hellish clouds of Venus may be the origin of life on Earth. A bizarre sighting 2,000 years ago raises the possibility that Earth once had two moons. A scientist helps the FBI crack the 1996 Olympic bombing.
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