Blurs

On 16 June 2016, NASA's Curiosity rover was travelling across Gale Crater on Mars when it photographed something that would later attract considerable attention online. Among the ordinary Martian rocks and weathered terrain was a small object with an unusually sharp, angular profile. To some observers, it looks remarkably like a miniature pyramid. The photograph was taken during Sol 1373 of Curiosity's mission — the 1,373rd Martian day since the rover landed on Mars in August 2012. NASA's archive contains multiple Mastcam images from that sol, including photographs taken on 16 and 17 June 2016. But what exactly are we looking at? A surprisingly geometric shape. The object is interesting because of its apparent geometry. Rather than having the irregular appearance normally associated with a heavily weathered rock, the visible portion has a pointed, wedge-like outline. In the right conditions, the human brain is exceptionally good at recognising familiar shapes.  A triangular...