MESSENGER measurements have revealed that Mercury is surprisingly abundant in volatile elements that evaporate at moderately high temperatures, ruling out many of the models for its formation and early history that had been proposed before the mission.Because potassium is much more volatile than thorium, the ratio of the abundances of these two elements is a sensitive measure of thermal processes that fractionate elements by volatility.Architectural lighting design is a field within architecture, interior design and electrical engineering that is concerned with the design of lighting systems, including natural light, electric light, or both, to serve human needs.The earliest form of artificial lighting used to illuminate an area were campfires or torches.Proper lighting can enhance task performance, improve the appearance of an area, or have positive psychological effects on occupants.Indoor lighting is usually accomplished using light fixtures, and is a key part of interior design.
For artworks, it may be sufficient to confirm whether a piece is broadly ancient or modern (that is, authentic or a fake), and this may be possible even if a precise date cannot be estimated.
Hundreds of hollowed worked stone lamps have been found in the Lascaux caves in modern-day France, dating to about 15,000 years ago.
Oily animals (birds and fish) were also used as lamps after being threaded with a wick. Gas lighting was economical enough to light streets in major cities starting in the early 1800s, and was also used in some commercial buildings and in the homes of wealthy people.
Daylighting (using windows, skylights, or light shelves) is sometimes used as the main source of light during daytime in buildings.
This can save energy in place of using artificial lighting, which represents a major component of energy consumption in buildings.
The gas mantle boosted the luminosity of utility lighting and of kerosene lamps.