The past is the portion of the timeline that has already occurred; it is the opposite of the future. It is also contrasted with the present. It is also regarded as the conglomerate of events that happened in a certain point in time, within the Space-time continuum. The aforementioned conception is closely related to Albert Einstein's relativity theory. Look up Future in Wiktionary, the free dictionary. ... The present is the time that is perceived directly, not as a recollection or a speculation. ... In physics, spacetime is a mathematical model that combines three-dimensional space and one-dimensional time into a single construct called the space-time continuum, in which time plays the role of the 4th dimension. ... In special relativity and general relativity, time and three-dimensional space are treated together as a single four-dimensional pseudo-Riemannian manifold called spacetime. ... Einstein redirects here. ... Albert Einsteins theory of relativity is a set of two theories in physics: special relativity and general relativity. ...

In a strict sense, the past doesn't exist (at least physically), but humans have recorded the past since ancient times, and to some extent, one of the defining characteristics of human beings is that they are able to record the past, recall it, remember it and confront it with the current state of affairs, thus enabling them to plan accordingly for the future, and to theorise about it as well. Look up Future in Wiktionary, the free dictionary. ...

The past is the object of such fields as history, archaeology, archaeoastronomy, historical linguistics, geology (historical geology), paleontology, paleobotany, paleoethnobotany, palaeogeography, paleoclimatology, cosmology. History is the study of human behavior through time. ... Archaeology, archeology, or archology (from the Greek words αρχαίος = ancient and λόγος = word/speech/discourse) is the study of human cultures through the recovery, documentation and analysis of material remains and environmental data, including architecture, artifacts, biofacts, human remains, and landscapes. ... The sun rising over Stonehenge at the 2005 Summer Solstice Archaeoastronomy (also spelled Archeoastronomy) is the study of ancient or traditional astronomies in their cultural context, utilising archaeological and anthropological evidence. ... Historical linguistics (also diachronic linguistics or comparative linguistics) is primarily the study of the ways in which languages change over time. ... This article does not cite its references or sources. ... Historical geology is the use of the principles of geology to reconstruct and understand the history of the Earth. ... Paleontology or palaeontology (see Spelling differences) is the study of the history and development of life on Earth, including that of ancient plants and animals, based on the fossil record (evidence of their prehistoric existence as typically preserved in sedimentary rocks). ... Paleobotany (from the Greek words paleon = old and botanikos = of herbs) is the branch of paleontology dealing with the recovery and identification of plant remains from geological contexts, and their use in the reconstruction of past environments and the history of life. ... Paleoethnobotany, also known as archaeobotany in European (particularly British) academic circles, is the archaeological sub-field that studies plant remains from archaeological sites. ... Paleogeography (sometimes spelled palaeogeography) is the study of the ancient geologic environments of the Earths surface as preserved in the stratigraphic record. ... Paleoclimatology is the study of climate change taken on the scale of the entire history of the Earth. ... Cosmology, as a branch of astrophysics, is the study of the large-scale structure of the universe and is concerned with fundamental questions about its formation and evolution. ...

	Those who cannot remember the past are condemned to repeat it.[1]
	— George Santayana

Image File history File links Cquote1. ... Image File history File links Cquote2. ... George Santayana George Santayana (16 December 1863 in Madrid, Spain – 26 September 1952 in Rome, Italy), was a philosopher, essayist, poet, and novelist. ...

References

1. ^ http://www.eskimo.com/~hottub/software/programming_quotes.html

Related topics

• Memory
• Retro
• Antiquarian
• Fossil
• History

In psychology, memory is the ability of an organism to store, retain, and subsequently recall information. ... modern retro wallpaper Retro, short for retrospective, is a modern term used to describe things from a bygone era. ... An antiquarian or antiquary is one concerned with antiquities or things of the past. ... An ammonite fossil Eocene fossil fish of the genus Knightia Petrified wood fossil formed through permineralization. ... History is the study of human behavior through time. ...

See also

• Past tense