The division between light and dark over the north pole of Mercury, viewed from the BepiColombo spacecraftESA/BepiColombo/MTMThese pictures of Mercurys pockmarked surface are the last well see before the BepiColombo mission begins orbiting the solar systems innermost world in late 2026.Since launching in 2018, the joint European-Japanese BepiColombo spacecraft has flown by Mercury six times, using each successive approach to reduce its speed and adjust its flight path to make it easier to get into orbit. While the missions main scientific instruments havent yet been put to use, the spacecrafts monitoring cameras have given us some of the clearest views weve ever had of the Swift Planet. AdvertisementThe European Space Agency (ESA) has now released three of the most captivating images from BepiColombos most recent flyby on 8 January, taken from around 300 kilometres above Mercurys surface as it flew over the planets north pole and northern regions.It meant getting up at 5.30am, but once close-up images started to appear in our shared folder, it was worth it, says David Rothery at the Open University, UK. We had studied some simulated views in advance and used these to devise our imaging strategy, but what we saw was better than expected.The image above, taken over the planets north pole, shows the clear division between sunlight and darkness on Mercury, which researchers call the terminator line. Mercury has some of the hottest temperatures in the solar system where sunlight falls on its scorched surface, but it also has some of the coldest, in craters that are permanently shadowed by their rims. Voyage across the galaxy and beyond with our space newsletter every month.Sign up to newsletterSome of these shadowed crater regions can be seen lying along the terminator line in the image. It was great looking down on Mercurys north pole, and even seeing the sunlit tip of the central peak inside the crater Tolkien, whose floor is in permanent shadow, says Rothery.Scientists have found some evidence that these cratered regions contain frozen water. One of BepiColombos main mission objectives is to discover whether that water really exists, and how much there is.The vast volcanic plains on Mercury known as Borealis PlanitiaESA/BepiColombo/MTMMercury also contains an expansive volcanic plain known as Borealis Planitia, which BepiColombo spied on its flyby. Researchers think these plains were formed from vast lava flows more than 3 billion years ago that flooded existing craters, some of which can be seen in the above image. Most of these flooded plains are smooth, with a few impact craters that must have been formed more recently.The Caloris Basin, which at 1500 kilometres wide is Mercurys largest crater, appears as a semi-circular patch of lighter-coloured ground extending from the horizon towards the bottom left of the image. Scientists hope to learn more about how this crater, the Borealis Planitia and the solidified lava flows between are connected once BepiColombo starts orbiting the planet.Nathair Facula, thought to be a remnant of Mercurys largest ever volcanic eruption, is seen as a bright patch in this imageESA/BepiColombo/MTMThe bright region near the top of the planet in this image is called Nathair Facula, and researchers think it is the remnant of Mercurys largest ever volcanic eruption. The centre of the region is a 40-kilometre-wide volcanic vent, which appears to have been the source of at least three huge eruptions that spewed volcanic material for hundreds of kilometres.[Nathair Facula] was right on the verge of what we expected to be able to make out, but having published on it based on images from the previous NASA mission to Mercury, it was exciting to glimpse it again, says Rothery. It is a very important science target for several of BepiColombos instruments when we get into orbit, because it offers our best chance to work out what it is about Mercurys composition that has allowed explosive volcanic eruptions to continue through much of the planets history.Topics: