waterhole

Geography

For bird watchers, in dry or drought seasons, a waterhole becomes the best place to watch bird-life coming to bathe or drink, or both. The best times to watch are

• early morning
• From 4 pm till dark.

Art, mythology and ecology

As a symbol, the waterhole represents a resource during a time of scarcity, a thin channel connecting the present to the future for the local wildlife. It also represents a kind of peace, the center of an uneasy truce between wary prey and predators, the water becoming sacred ground and a place of drink and not food. As a drought becomes more severe the symbolism changes and the waterhole becomes a graveyard and a place of death, larger animals churn the edges, the last available drinking water jealously guarded by a corona of sucking mud

Astronomy

The radio frequency band between the neutral hydrogen line at 1,420 MHz (21-centimeter line) and the hydroxyl (OH) line at 1,662 MHz. It lies in a part of the radio spectrum in which there is relatively little noise from natural celestial sources, so that a directional transmitter of only modest power would be needed to produce a detectable signal over interstellar distances. The waterhole was first identified as a prime region of the radio spectrum in which to carry out searches for intelligent signals in the Project Cyclops report prepared in 1971 by Bernard Oliver and John Billingham

Nature has provided us with a rather narrow band in this best part of the spectrum that seems especially marked for interstellar contact. . . . Standing like the Om and the Um on either side of a gate, these two emissions of the disassociation products of water beckon all water-based life to search for its kind at the age-old meeting place of all species: the waterhole.