Can you make out the dot at the bottom of this question mark? What if you stand a few metres away? The finest detail the average human eye can distinguish is about the size of a full stop seen at a distance of a metre. This is called "resolution". The best resolution for an optical system – like the eye – is roughly given by the ratio of the wavelength of the light you're viewing in and the size of the aperture that light is passing through.
In astronomy, resolution works just the same. This explains why we build increasingly large telescopes: not only can big telescopes collect more light and therefore see further, the bigger the aperture of the telescope, in principle the better the image.
But now a new study has suggested that the universe actually has a fundamental resolution limit, meaning no matter how big we build our telescopes we won't see the most distant galaxies as clearly as we would like.To read more, click here.