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The past is the portion of time
Time

Time is a component of the measurement used to sequence events, to compare the durations of events and the intervals between them, and to quantify the motions of objects....
 that has already occurred; it is the opposite of the future
Future

The future is a time period commonly understood to contain all events that have yet to occur. It is the opposite of the past, and is the time after the present....
.

past is contrasted with the present
Present

Present may refer to:...
. It is also regarded as the conglomerate of events
Spacetime

In physics, spacetime is any mathematical model that combines space and Time in physics into a single continuum . Spacetime is usually interpreted with space being Three-dimensional space and time playing the role of a fourth dimension that is of a different sort than the spatial dimensions....
 that happened in a certain point in time, within the Space-time continuum.






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Maximov Everything in the Past
The past is the portion of time
Time

Time is a component of the measurement used to sequence events, to compare the durations of events and the intervals between them, and to quantify the motions of objects....
 that has already occurred; it is the opposite of the future
Future

The future is a time period commonly understood to contain all events that have yet to occur. It is the opposite of the past, and is the time after the present....
.

Overview

The past is contrasted with the present
Present

Present may refer to:...
. It is also regarded as the conglomerate of events
Spacetime

In physics, spacetime is any mathematical model that combines space and Time in physics into a single continuum . Spacetime is usually interpreted with space being Three-dimensional space and time playing the role of a fourth dimension that is of a different sort than the spatial dimensions....
 that happened in a certain point in time, within the Space-time continuum. The aforementioned conception is closely related to Albert Einstein
Albert Einstein

Albert Einstein was a Germany-born theoretical physics. He is best known for his theory of relativity and specifically mass?energy equivalence, expressed by the equation E = mc2....
's relativity theory. The past is the object of such fields as history
HIStory

HIStory: Past, Present and Future, Book I is a double album by Michael Jackson, released on June 20, 1995, and is Jackson's ninth. The first disc, named "HIStory Begins" consists of a selection of Jackson's greatest hits from the singer's past fifteen years, while the second, named "HIStory Continues" features new songs, with the...
, archaeology
Archaeology

Archaeology, archeology, or arch?ology is the science that studies Homo cultures through the recovery, documentation, analysis, and interpretation of material remains and environmental data, including architecture, Artifact , features, Biofact s, and cultural landscape....
, archaeoastronomy
Archaeoastronomy

Archaeoastronomy is the study of how past people "have understood the phenomenon in the sky, how they used phenomena in the sky and what role the sky played in their cultures." Clive Ruggles argues it specifically is not the study of ancient astronomy, as astronomy is a culturally specific concept and ancient peoples may have related t...
, chronology
Chronology

Chronology is a chronicle or arrangement of events in their occurrence order. General chronology is the science of locating and resolution of temporal sequence of past events in time...
, geology
Geology

Geology is the science and study of the solid and liquid matter that constitute the Earth. The field of geology encompasses the study of the composition, structural geology, physical properties, dynamics, and History of the Earth of Earth materials, and the processes by which they are formed, moved, and changed....
, (historical geology
Historical geology

Historical geology is the use of the principles of geology to reconstruct and understand the Geological history of Earth . It focuses on geologic processes that change the Earth's surface and subsurface; and the use of stratigraphy, structural geology and paleontology to tell the sequence of these events....
), historical linguistics
Historical linguistics

Historical linguistics is the study of language change. It has five main concerns:* to describe and account for observed changes in particular languages;...
, law
LAW

LAW may refer to:* Anti-tank warfare, e.g. the US Army M72 LAW or the British Army LAW 80*Palestinian Society for the Protection of Human Rights ...
, paleontology
Paleontology

File:Geological time spiral - sharper.pngPaleontology from Greek: pa?a??? "old, ancient", ??, ??t- "being, creature", and ????? "speech, thought" is the study of prehistory life, including organisms' evolution and interactions with each other and their environments ....
, paleobotany
Paleobotany

Paleobotany, also spelled as palaeobotany , is the branch of paleontology or paleobiology dealing with the recovery and identification of plant remains from geology contexts, and their use for the biological reconstruction of paleogeographys, and the evolution of both the Evolutionary history of plants kingdom and Evolution of life in...
, paleoethnobotany
Paleoethnobotany

Paleoethnobotany, also known as archaeobotany in European academic circles, is the archaeology sub-field that studies plant remains from archaeological sites....
, palaeogeography
Palaeogeography

Palaeogeography is the study of what the geography was in times past. It is most often used about the physical landscape, although nothing excludes that the word also be used about the human or cultural environment....
, paleoclimatology
Paleoclimatology

Paleoclimatology is the study of climate change taken on the scale of the entire history of Earth. It uses records from ice sheets, tree rings, sediment, and rock s to determine the past state of the climate system on Earth....
, and cosmology
Physical cosmology

Physical cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of our universe and is concerned with fundamental questions about its formation and evolution....
.

Humans have recorded the past
Recorded history

Recorded history can be defined as human history that has been written down or recorded by the use of language, whereas history is a more general term referring to any information about 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
HIStory

HIStory: Past, Present and Future, Book I is a double album by Michael Jackson, released on June 20, 1995, and is Jackson's ninth. The first disc, named "HIStory Begins" consists of a selection of Jackson's greatest hits from the singer's past fifteen years, while the second, named "HIStory Continues" features new songs, with the...
, recall it, remember it and confront it with the current state of affairs, thus enabling them to plan accordingly for the future
Future

The future is a time period commonly understood to contain all events that have yet to occur. It is the opposite of the past, and is the time after the present....
, and to theorise about it as well.

Philosophy and science

According to presentism
Presentism (philosophy of time)

In the philosophy of time, presentism is the theory that only the present existence and the future and the past are reality. Past and future "entities" are to be construed as logical constructions or fictionalism....
, the past does not strictly exist; however, the methods of all sciences study the world's past, through the process of evaluating evidence. Presentism is compatible with Galilean relativity, in which time is independent of space but is probably incompatible with Lorentzian/Einsteinian relativity in conjunction with certain other philosophical theses which many find uncontroversial.

In classical physics
Classical physics

Classical physics is a general term used to describe the branches of physics based on principles developed before the rise of general theory of relativity and Quantum mechanics, usually including special theory of relativity....
 the past is just a half of the timeline. In special relativity
Special relativity

Special relativity is the physical theory of measurement in inertial frames of reference proposed in 1905 by Albert Einstein in the paper "Annus Mirabilis Papers#Special relativity"....
 the past is considered as absolute past or the past cone
Light cone

In special relativity, a light cone is the surface describing the temporal evolution of a flash of light in Minkowski spacetime. This can be visualized in 3-space if the two horizontal axes are chosen to be spatial dimensions, while the vertical axis is time....
. In Earth's scale the difference between "classical" and "relativist" past is less than 0.05 s
Second

The second , sometimes abbreviated sec., is the name of a units of measurement of time, and is the International System of Units SI base unit of time....
, so it can be neglected in most cases.

In the modern theory of relativity
Theory of relativity

File:spacetime curvature.pngThe theory of relativity, or simply relativity, generally refers specifically to two theories of Albert Einstein: special relativity and general relativity....
, the conceptual observer
Observation

Observation is either an activity of a living being , consisting of receiving knowledge of the outside world through the senses, or the recording of data using scientific instruments....
 is at a geometric point
Point (geometry)

In geometry, topology and related branches of mathematics a spatial point describes a specific object within a given space that consists of neither volume, area, length, nor any other higher dimensional analogue....
 in both space and time at the apex of the 'light cone
Light cone

In special relativity, a light cone is the surface describing the temporal evolution of a flash of light in Minkowski spacetime. This can be visualized in 3-space if the two horizontal axes are chosen to be spatial dimensions, while the vertical axis is time....
' which observes events laid out in time as well as space. Different observers can disagree on whether two events at different locations occurred simultaneously depending if the observers are in relative motion (see relativity of simultaneity
Relativity of simultaneity

The relativity of simultaneity is the concept that simultaneity is not absolute, but dependent on the observer. That is, according to the special theory of relativity formulated by Albert Einstein in 1905, it is impossible to say in an absolute sense whether two events occur at the same time if those events are separated in space....
). This theory depends upon the idea of time as an extended thing and has been confirmed by experiment and has given rise to a philosophical viewpoint known as four dimensionalism
Four dimensionalism

Four dimensionalism is an ontology view concerned with how objects persist in time. The proponents of four dimensionalism claim that both past and future objects lay equal claims to having the same level of reality as does the present moment....
. However, although the contents of an observation are time-extended, the conceptual observer, being a geometric point at the origin of the light cone, is not extended in time or space. This analysis contains a paradox
Paradox

A paradox is a Proposition or group of statements that leads to a contradiction or a situation which defies intuition ; or, it can be an apparent contradiction that actually expresses a non-dual truth ....
 in which the conceptual observer contains nothing, even though any real observer would need to be the extended contents of an observation to exist. This paradox is partially resolved in Relativity theory by defining a 'frame of reference
Frame of reference

A frame of reference in physics, may refer to a coordinate system or Cartesian coordinate system within which to measure the position, orientation , and other properties of objects in it, or it may refer to an observational reference frame tied to the state of motion of an Observer ....
' to encompass the measuring instruments used by an observer. This reduces the time separation between instruments to a set of constant intervals.

Quote


See also

  • Antiquarian
    Antiquarian

    An antiquarian or antiquary is an aficionado of antiquities or things of the past. Also, and most often in modern usage, an antiquarian is a person who deals with or collects rare and ancient "Antiquarian book trade in the United States"....
  • Fossil
    Fossil

    Fossils are the preserved remains or trace fossil of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous Rock formations and sedimentary rock layers is known as the fossil record....
  • Memory
    Memory

    In psychology, memory is an organism's mental ability to store, retain and recall information. Traditional studies of memory began in the fields of philosophy, including techniques of mnemonic....
  • Past tense
    Past tense

    The past tense is a verb grammatical tense expressing action, activity, state or being in the past of the current moment , or prior to some other event, whether that is past, present, or future ....
  • Retro
    Retro

    Retro is a term used to describe, denote or classify culturally outdated or aged trends, modes, or fashions, from the overall postmodern past, but have since that time become functionally or superficially the norm once again....
  • Nostalgia
    Nostalgia

    The term nostalgia describes a longing for the past, often in idealisation form. The word is made up of two Greek roots , to refer to "the pain a sick person feels because he wishes to return to his native home, and fears never to see it again"....
  • Museum
    Museum

    A museum is a "permanent institution in the service of society and of its development, open to the public, which acquires, conserves, researches, communicates and exhibits the tangible and intangible heritage of humanity and its environment, for the purposes of education, study, and entertainment", as defined by the International Coun...
  • Artifact
    Artifact

    Artifact or artefact may refer to:* Artifact , any object made or modified by a human culture, and later recovered by an archaeological endeavor...
  • History
    HIStory

    HIStory: Past, Present and Future, Book I is a double album by Michael Jackson, released on June 20, 1995, and is Jackson's ninth. The first disc, named "HIStory Begins" consists of a selection of Jackson's greatest hits from the singer's past fifteen years, while the second, named "HIStory Continues" features new songs, with the...
  • Historic preservation
    Historic preservation

    Historic preservation or heritage conservation is a professional endeavor that seeks to preserve the ability of older objects to communicate an intended meaning....