If we ever find a real cannonball on Mars, it would make us question everything we know about the history of the red planet. That transformative moment has not happened yet.
The Twitter account of NASA's Mars Curiosity rover posted an intriguing message on Tuesday that highlights some spherical objects found on the planet:
The Curiosity image shows a delightfully round shape sitting on the dusty surface of Mars. Although the rover first took pictures of the area in late 2016 and early 2017, the photos are receiving renewed attention thanks to a December 2 post on the popular alien blog UFO Sightings Daily, which refers to the round shape as a "cannonball" "about the size of a softball and suggests it is evidence of a war on Mars.
NASA says that the sphere is less than a quarter of an inch (5 millimeters) in size and composed of calcium, sodium, and magnesium sulfate.
The tweet also includes an image taken in 2004 by NASA's Opportunity rover, of a collection of spherules known as "blueberries," which shows how round concretions really are not so strange on Mars, as a reference, those hematite-rich spheres are only the size of BB's granules, erosion eventually left "blueberries" exposed.
See strange things in Ma rte has been an entertaining hobby since 1976, when NASA's Viking 1 mission revealed a "face on Mars" that the space agency says is really an old low hill. Since then, we have fantastically seen everything from a "" to an .
All this is very funny, but, as the cannon does not show us, everything (so far) has a perfectly mundane explanation.