Rhodamine dyes fluoresce and can thus be detected easily and inexpensively with instruments called fluorometers.

Such approaches, though, make the assumption that the radiant energy generated by civilization would be relatively clustered and can therefore be detected easily.

Currency printed by local racketeers can be detected easily as they use the photographic method, hand engraved blocks, lithographic processes and computer colour scanning.

That means long-range structural variants can be detected easily.

It can be detected easily by most wireless intrusion detection systems, because it actively probes a network to collect information.