Mystery of Planet 9

8.4/10 · 98 votesNov 29, 201642 min

Ranked #3 of 8 in Season 5•matches the season avg

Discussion

Scientists have discovered a mysterious ninth planet on the very edge of our solar system. Ten times the size of Earth, this strange world could have moons with extraterrestrial life.

Previous episodeE1 · Most Amazing Discoveries Next episodeE3 · Black Holes: The Secret Origin

Seasons11

All 1 2 3 4 5 6 7 8 9 10 11

Season 5 Episodes9

E1 8.4

Most Amazing Discoveries

E2 8.4Now viewing

Mystery of Planet 9

E3 8.5

Black Holes: The Secret Origin

E4 8.4

Secret History of Pluto

E5 8.4

Stars That Kill

E6 8.3

The Universe's Deadliest

E7 8.2

Life and Death on the Red Planet

E8 8.3

The Dark Matter Enigma

Strangest Alien Worlds

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Episode Summary

"Mystery of Planet 9" is episode 2 of How the Universe Works season 5. It scored 8.4/10 from 98 votes, ranking #3 of 8 episodes this season (season average 8.4). It aired on November 29, 2016.

Next: E3 · Black Holes: The Secret Origin Best of Season 5