A spinning blueish-white spiral was spotted in the sky on Monday night - leaving people starstruck. Some posted the stunning images on social media, joking that they thought it could be 'aliens' or a portal to another world. But the bizarre shape was caused by illuminated frozen fuel expelled from on of Elon Musk’s SpaceX rockets, experts have said. The light blue spiral is formed when excess fuel that has been released from the fast-spinning rocket turns to ice, and then water vapour. It then reflects the sunlight in the upper atmosphere – giving it an otherworldly gleam. The stunning swirl was spotted from Yorkshire, Hertfordshire, Bristol, Milton Keynes, Stoke-on-Trent, Hampshire and Kent. Met Office said in an X post that it had received 'many reports of an illuminated swirl in the sky' late on Monday. 🎥 YappApp Read more at DailyMail.com #britain #mystery #space #spacex #sky #elonmusk #fuel