Didn�t you evolve a way of checking whether something had a cloaking device?

Yeah, we�d worked that one out by Next Generation. The give away for a cloaking device in the 24th century is that there is a sort of little neutrino leakage from the cloak. Neutrinos are these very ephemeral, sub-atomic particles. They�re produced in stars and trillions of them are passing through your body every second. They have no or very little mass and they have no charge.

Even the best best cloaking system probably couldn't marshal in all of those neutrinos that are coming from sources with, for example, the warp core of a ship. So, if you have good neutrino detectors on your ship, you may well be able to detect a cloaked ship by noticing an unusual level of neutrinos in some location in space and say: 'Hey, where would those be coming from? There�s no star there, there�s no other source of neutrinos. Maybe it�s a cloaked ship.'