'Alien' is defined as 'a hypothetical or fictional being from another world', which just about hits the nail on the head. For countless years, mankind has been obsessed with what lies above, whether in the form of deities or little green men in an unidentified flying object. And when science developed the technology that probing the universe was finally possible, Earth leaped at the opportunity.
The search for extraterrestrial life has been a popular subject for the past century, and yet it doesn't feel like any significant progress has been made towards discovering Earth's neighbors in the universe. The scientific community is divided on why alien life proves so elusive, maybe because there's very little that smart people agree on. But it's a good idea to be well-informed on the possibilities, so you can tell your alien friends in 2045 that you knew it all along
Picture what a two-dimensional being would be like. It would be flat because it would lack depth. Its surroundings would similarly only be measured by length and width as well. A two-dimensional being would be unable to comprehend or even look upon a three-dimensional being such as humans. Now imagine how a four-dimension being would seem to us with our measly three dimensions.
When a scientist talks about dimensions, they most likely mean a set of numbers by which space is measured. In the case of three dimensions, the measurements length, width, and depth. Scientists are unsure of what the fourth dimension could be, though the most common hypothesis is time, meaning that these theoretical creatures exist out of a linear perception of time.
This theory posits that aliens do exist and may have discovered us, and they might even be more populous than us. They could exist in the same space that people do, but humans aren't able to perceive or understand such a high level being such as that. So, you never have to feel alone. Even when you settle down to sleep tonight, take a look at your empty bedroom, and maybe a 4-D creature is watching you. Sleep tight.