According to our current understanding of physics, an object with mass, such as a person, cannot reach or exceed the speed of light. The theory of relativity, proposed by Albert Einstein, states that as an object with mass approaches the speed of light, its relativistic mass increases, and the amount of energy required to accelerate it further also increases. At the speed of light, the relativistic mass would become infinite, which is not physically attainable.
However, let's consider a hypothetical scenario where a person could travel at the speed of light. In this scenario, the effects of time dilation and length contraction, as predicted by the theory of relativity, would come into play. From the perspective of the person traveling at the speed of light, time would appear to stand still, and distances in the direction of motion would contract to zero.
From the perspective of an observer on Earth, it would still be impossible to accelerate a massive object to the speed of light, but let's assume the person magically achieves this speed. In that case, according to the observer on Earth, the person would appear to take an infinite amount of time to reach Earth. This is because, due to time dilation, the time experienced by the person traveling at the speed of light would be frozen from the observer's perspective.
So, in this hypothetical scenario, the person traveling at the speed of light would not hit an invisible wall or keep going into outer space forever. Instead, they would appear to be frozen in time from the perspective of an observer on Earth, and the distance between them and Earth would never decrease.