The fourth planet circling the distant star Sutterer 4041? in the Dune Universe. It was named after Levas Crompton, the captain of the Guild ship Tharondelai, who first officially discovered it in 14701 AG; it was home to the enigmatic Crompton Ruins.
Crompton's ecosystem was nearly ideal for human habitation, with only the relatively high water vapour content in the atmosphere a minor inconvenience.
The discovery of the Ruins confirmed that other lifeforms, almost certainly human, had visited the planet before the arrival of the first Crompton expedition.
In 14702 AG, a follow up expedition was sent to catalog the planet, its resources, and to do a thorough scientific study. A low altitude satellite detected an artificial structure on the surface. Working under long standing regulations concerning alien contact, Captain Reola senShek directed continuous reconnaissance on the site. A ground crew was eventually sent to the now called "Crompton Ruins" and investigations discovered no intelligent life, the structure was estimated to be 3000 to 5000 years old. As far as the Guild could determine (and they were certainly in a position to be definite) no human being had ever set foot on Crompton.
A second expedition of 5 heighliners and a mass of equipment discovered synthetic materials, but nothing definitive. The structure was completely empty and ferric oxides found were speculated to be the remains of construction equipment that had totally decomposed. There the matter rested as a beacon to the discovery of alien life in the galaxy.
Then came the Rakis Finds.
It was archaeologist Joona Krtipar whom pointed out that if Leto II Atreides's no-room were a free standing structure, instead of an excavation, and if the heights of the different floors varied instead of being constant, the no-room would be only a slightly smaller duplicate of the Crompton Ruins.
The Crompton Ruins theory of aliens was demolished. Many pointed out that nothing had changed, only the questions, instead of where were the aliens, the question now is when did Leto II send construction crews to Crompton and why?
Sources: Dune Encyclopedia?