Proxima Centauri b is a planet orbiting the star Proxima Centauri.

[6EQUJ5]

Proxima Centauri b is tidally locked. That is it does not spin. Thus when it orbits Proxima Centauri it always shows the same half to the star. The other half is in permanent natural darkness. The half that faces the star is uninhabitable because the direct ultraviolet light from the star reaches its surface. This light contains radiation such that no life can survive. (We survive our Sun's light because the Ozone Layer prevents nearly all of the radiation from getting through.)

The half of Proxima Centauri b that is always in natural darkness is attracting attention from scientists. This is because they have reason to believe that on this dark side of the planet there is a possibility that there may be light that is not produced in nature. It is extremely difficult to investigate this possibility but there are people working on it. Lots of people know about this. A few are getting excited about the implications.

Proxima Centauri b is a distance of 4.24 light years from Earth. If we could travel at the speed of light it would take 4.24 years to get there. The fastest crewed craft that we have built thus far would need to have its top speed increased by 270 times to reach a little less than 1% of the speed of light. So we are not going there and 'they' are not coming to Earth. Radio messages can travel at the speed of light and thus they would take 4.24 years to do the one way journey.

It is a fundamental law of physics that the only thing with mass that can move faster than the speed of light is the continuously expanding universe. Otherwise, the only other things that can move at the speed of light are objects without mass, i.e. signals in the radio spectrum such as radio signals, television signals, radar signals, laser light etc. This speed limit tends to annoy the folk who fantasize about the technologies of their imagined aliens. There may well be aliens but they cannot travel at anywhere near to the speed of light.