In the very early hours of the morning on Friday the 18th of September 2015 (approximately 12:20 AM) I was laying in bed almost asleep, when I heard a strange noise that sounded exactly like what you'd imagine a UFO descending to a stop would sound like (or atleast what it's been said to sound like).At that time I sprang out of bed, walked out the back door & stood on the pavement in my backyard looking vigorously up at the night sky for answers. About 15 minutes had elapsed and I couldn't see anything out of the ordinary (apart from a few lights that I thought appeared to be moving, may have just been stars) & although I was very intrigued - I decided to go back to bed.I awoke the next morning to find something astonishing, something that has no logical explanation.In the exact spot where I was standing on the pavement for those 15 minutes gazing up at the sky, a small bright circle has mysteriously appeared.I live at home with my parents and I queried them about it that next day - Neither of them had ever seen it before & they had not even the slightest idea as to where it had come from. It's still baffling us a few months later.In my truly honest opinion I feel that there is no other reasonable explanation for the origin of this circle other than some sort of extraterrestrial involvement.I think it's important to add that I live in a quiet neighbourhood, my backyard is quite small & is fully fenced, therefore I don't believe it's plausible to suggest that somebody 'snuck in' during the night to make this circle.(And for what reason would someone want to do that for anyway). I have attached 2 pictures of the circle-The first picture was taken just after it happened & the second picture was taken just recently.I'm hoping to get some tests done on the circle in the near future to determine whether it has any radioactive properties, but haven't had the chance to do so yet.Thank you for reading.