If you look out on the sky on a nice clear dark night, you’ll see thousands of intense points of light. Those stars are incredibly far away, but bright enough to be seen with the naked eye from that great distance—a considerable feat. But what you don’t see are all the small stars, the red dwarfs, too small and dim to be seen at those same distances.
Source:
https://phys.org/news/2020-05-future-universe-invisible.html