The universe is so vast; you can't confidently say that we are the only ones living here. Maybe we're not up to a point in time in which we can explore the worlds outside of the Earth, especially we don't have the equipment to last long and withstand extreme temperatures of other planets. There is so much out there, it may not be in our time, but there will be a big chance our future generations can truly meet and interact with extraterrestrials.