Is there anybody out there? Are we really alone in the universe, or are aliens just patiently waiting for us to become advanced enough to be worth speaking to?
There are so many mysteries about who or what might live among the stars, and whether they are advanced planet-hopping civilizations or microbes quietly doing what microbes do on a nearby moon. But some questions are easier to answer.
This extraterrestrial quiz is your chance to show whether you know the facts from the fiction about otherworldly entities, or if it's all alien to you. Remember to log in to put your name on the leaderboard; hints are available if you click the yellow button, and let us know your score in the comments.
Related: 32 strange places scientists are looking for aliens
More science quizzes
—Moon landing quiz: How quickly can you name all 12 Apollo astronauts that walked on the moon?
—Conspiracy theory quiz: Test your knowledge of unfounded beliefs, from flat Earth to lizard people
—Black hole quiz: How supermassive is your knowledge of the universe?
