A mysterious rock , shaped and sized like a doughnut , has appeared on Mars . It's been there for billions of years! Rock appeared in photo , 12 days after previous photo showed no rock . There are two leading theories about where the rock , called `` Pinnacle Island , '' came from . Opportunity has been exploring Mars since January 2004 .
A mysterious rock , shaped and sized like a doughnut , has appeared on Mars . It's been there for billions of years! Rock appeared in photo , 12 days after previous photo showed no rock . Opportunity has been exploring Mars since January 2004 .