If we see two people talking atadistance of around two feet from each other, we assume they are engaged in the kind of conversation only possible between those who know and trust each other.
"We compared what you see in these galaxies with what you see in the field galaxy population, other galaxies at the same epoch and distance, and there is a stark difference - far more star formation and black hole growth, " the Cambridge University scientist and Royal Society research fellow explained to the BBC News website.