Humanity has not yet found real, concrete and scientifically backed evidence of extraterrestrial life. We have come very close, and have discovered some chemical markers and other indications that could suggest that life once existed elsewhere than on Earth, but hunting still stands for indisputable proof. Well, some Mars observers now believe they've found it, and it's in the shape of a "cannonball."
An oddly shaped object was captured in the camera by the Mars Curiosity rover, lying on the dusty, rocky, red sloping surface of the planet. It's a ball, and it seems completely out of place. A bluish gray orb sitting on top of a sea of red. Foreign hunters say it is a cannonball fired during an ancient Martian war. NASA, as expected, says they are crazy.
If you have not been following the endless stream of conspiracy theories related to Mars lately, let me catch up: NASA has taken many photos of the planet with its various rovers and orbiters, and then releases huge dumps of those images to the public. When that happens, amateur astronomers and alien hunters always find some kind of "evidence" that suggests that Mars was once inhabited by an alien civilization. NASA always has an explanation for these sightings, but they fall on deaf ears, and Mars's alien cover-up conspiracy is born again.
The "cannonball" discovered by Curiosity is another hot topic for the debate, and supporters of the conspiracy say there is no way such an object can exist on the red planet unless some intelligent civilization is responsible for its creation. NASA says that everything is just a bunch of culinary conversations.
NASA is too familiar with strange spheres, and this is not exactly the first time scientists have detected them on the surface. In fact, they are so common that NASA has a nickname for them: "blueberries." According to the space agency, peculiar objects are the result of a natural phenomenon called concretion, in which minerals gather and harden within the rock soaked in water. Taking shapes similar to bubbles, they are more resistant to erosion than the surrounding rock, and when that material erodes, the strange colored spheres are left behind.
Of course, if you already believe that NASA has been hiding evidence from extraterrestrials for decades, it probably will not buy that explanation. Some amateur UFO hunters are positive that the spheres are actually cannonballs fired from space to Mars, and are clear evidence of an ancient alien war that left Mars in the state it is today.