Ridge A is a site in Antarctica that was identified in 2009 as the best suited location on the surface of Earth for astronomical research.

[1][2] Ridge A was identified by a team of Australian and American scientists searching for the best observatory spot in the world.

It is also the site of a vortex in which swirling stratospheric winds high up and calm air at ground level combine to make it a place for viewing into space that is three times clearer than any other location on Earth.

[5] Since January 2012, a small international observatory, the High Elevation Antarctic Terahertz (HEAT) telescope, has operated at Ridge A, jointly run by American and Australian researchers.

[6] By virtue of the weather, this submillimetre or terahertz telescope is capable of observing wavelengths of light that rarely make it through the atmosphere to the ground anywhere else on Earth.