Blurs

Mars is home to Olympus Mons, the tallest known volcano in the Solar System. But another Martian volcano presents an equally remarkable mystery — not because it is exceptionally tall, but because of how extraordinarily wide and shallow it is. That volcano is Alba Mons. Stretching across hundreds of kilometres, Alba Mons is one of the largest volcanic structures ever identified on a planetary body. NASA describes it as the largest volcano by area on Mars, while the USGS planetary nomenclature database officially recognises Alba Mons as a Martian mons. And compared with Olympus Mons, its shape is almost bizarre. A Mountain That Spreads Instead of Soaring When we picture a mountain, we normally imagine something rising dramatically from its surroundings. Alba Mons doesn't really behave that way. Its slopes are extraordinarily gentle. The volcano is so broad that from the surface, its enormous size would be difficult to appreciate. NASA estimates that the broader Alba volcanic structur...

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...

The first crewed mission to Mars is often imagined as the beginning of humanity's journey to another world.  But getting astronauts there is only half the problem. Can we actually bring them home? Mars has fascinated humanity for centuries. From the canals imagined by nineteenth-century astronomers to today's robotic explorers, the Red Planet has gradually changed from a distant point of light into a destination. But there is a question that receives surprisingly less attention than the journey there: If humans eventually land on Mars, will they actually be able to come back? A mission to Mars is not simply a longer version of a trip to the Moon. The distances are enormous, launch windows are limited, communication is delayed and returning a crew safely requires spacecraft, fuel, power and life-support systems to work hundreds of millions of kilometres from Earth. And unlike the Apollo missions, astronauts travelling to Mars could be away from Earth for years. Mars Is a Long Wa...