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...

Around 74,000 years ago, something happened that makes almost every volcanic eruption in human history look insignificant. A volcano in what is now Indonesia erupted with extraordinary force. The eruption was so enormous that it left behind a vast volcanic depression known as the Toba caldera. Millions of tonnes of volcanic material were blasted into the atmosphere. Ash travelled enormous distances. The climate was affected.  And the eruption occurred at a critical point in human prehistory. Our species already existed, but humanity was far from dominant. There were relatively small populations of Homo sapiens scattered across Africa and perhaps beyond. Other human species were still alive. Neanderthals occupied large parts of Europe and western Asia. Denisovans lived somewhere across Asia. And numerous populations of other hominins had existed before them. Then Toba erupted. The obvious question is: Did this enormous volcanic catastrophe change the course of human evolution? Perha...