At the beginning of this month there were only two teams in the large group so Terry amalgamated them into the Medium group and renamed it as Large (because it makes more sense to have Small and Large rather than Small and Medium). The requirements you have to meet in Heroes are the same as before.
The key number that determines your category is the number of active players you have, not whether they play or not.
The Hubble Telescope has just picked up a sound from a fraction of a second before the Big Bang. The sound was "Uh oh".