In September 2012, Nasa released a picture of the Curiosity, a rover that was exploring Mars. A regular photo of the rover's exploration containing a mysterious shadow intrigued the internet and raised questions.

Catch full episodes of your favourite Quest shows here:
https://www.discoveryplus.co.uk/
Subscribe to Quest TV for more great clips:
   / subscription_c.  .


Follow Quest on Twitter:
  / questtv