Great Moments In Science Folgen

We're now quite familiar with terms like 'herd immunity' and 'epidemic', and that when separate groups of people—with separate germs—meet for the very first time, things can turn out badly. If you have never been exposed to a specific germ you won't be primed for protection against it.

When digging the compost pile into the garden, Dr Karl noticed a ball of entangled shape-shifting worms. You might think 'yuck'—but there's a 'wow' factor because some animal groupings can generate intelligence, giving the group an advantage over solitary individuals.

The final piece about why the 100 million or so black holes in our Milky Way galaxy are missing.