Antimatter Article

A nonspatial continuum in which events occur in apparently irreversible succession from the past through the present to the future. An interval separating two points on this continuum; a duration: a long time since the last war; passed the time reading. In physics, force is what causes a mass to accelerate. It may be experienced as a twist, a push, or a pull. In physics and other sciences, energy (from the Greek ενεργός, energos, "active, working")^[1] is a scalar physical quantity that is a property of objects and systems which is conserved by nature. Energy is often defined as the ability to do work. Mass is a fundamental concept in physics, roughly corresponding to the intuitive idea of "how much matter there is in an object". Mass is a central concept of classical mechanics and related subjects, and there are several definitions of mass within the framework of relativistic kinematics (see mass in special relativity and mass in General Relativity). Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields. In the scientific method, an experiment (Latin: ex- periri, "of (or from) trying") is a set of observations performed in the context of solving a particular problem or question, to retain or falsify a hypothesis or research concerning phenomena. The experiment is a cornerstone in the empirical approach to acquiring deeper knowledge about the physical world. Nature, in the broadest sense, is the natural world, physical universe, material world or material universe. "Nature" refers to the phenomena of the physical world, and also to life in general. An entity is something that has a distinct, separate existence, though it need not be a material existence. In particular, abstractions and legal fictions are usually regarded as entities. In physics, the photon is the elementary particle (specifically, a boson) responsible for electromagnetic phenomena. It is the carrier of electromagnetic radiation of all wavelengths, including gamma rays, X-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves. Light, or visible light, is electromagnetic radiation of a wavelength that is visible to the human eye (about 400–700 nm). In a scientific context, the word light is sometimes used to refer to the entire electromagnetic spectrum.^{[1]
The Egyptians (Egyptian:
rmṯnkm.t;

Coptic:

ⲛⲓⲣⲉⲙ'ⲛⲭⲏⲙⲓ ni.ramenkīmi;

Arabic: مِصريّون
miṣriyūn;

Masri: مَصريين
maṣreyyīn) are a

nation and a

North African ethnic group native to

Egypt. Egyptian identity is rooted in the
lower

Nile Valley, the small strip of cultivatable
land stretching from the

First Cataract to the

Mediterranean Sea and enclosed by vast
deserts. Earth (pronounced

/ˈɝːθ/^[5])
is the third

planet from the

Sun and is the largest of the

terrestrial planets in the

Solar System, in both

diameter and

mass. It is also referred to as the Earth,
Planet Earth, and the

World, and in some contexts,

Gaia and

Terra.^{[6]
A chemical substance is a material with a
definite

chemical composition. It is a

concept that became firmly established in
the late eighteenth century after work by the
chemist

Joseph Proust on the composition of some
pure chemical compounds such as

basic copper carbonate.^{[1]
A chemical reaction is a process that
always results in the interconversion of

chemical substances.^[1]
The substance or substances initially involved
in a chemical reaction are called

reactants. In the

history of science, alchemy from
Arabic (al-kimia) refers to both an early
form of the investigation of

nature and an early

philosophical and

spiritual discipline, both combining
elements of

chemistry,

metallurgy,

physics,

medicine,

astrology,

semiotics,

mysticism,

spiritualism, and

art all as parts of one greater force.
Alchemy has been practiced in

Mesopotamia,

Ancient Egypt,

Persia,

India,

Japan,

Korea and

China, in

Classical

Greece and

Rome, in the

Muslim civilization, and then in

Europe up to the 19th century—in a complex

network of schools and philosophical systems
spanning at least 2500 years.}}A
revolution (from the

Latin revolutio, "a turnaround") is a
significant

change that usually takes place in a short
period of time.

Aristotle described two types of political
revolution: Complete change from one
constitution to another. Modification of an
existing constitution.^[1]An
atom is the smallest particle
characterizing a

chemical element. An atom consists of an
electron cloud surrounding a dense

nucleus. The electron is a

fundamental

subatomic particle that carries a negative

electric charge. It is a spin ½

lepton that participates in

electromagnetic interactions, its mass is
approximately 1 / 1836
of the

proton. In

physics and chemistry, spin has a
special meaning, representing a non-classical
kind of

angular momentum intrinsic to a body, as
opposed to

orbital angular momentum, which is the
motion of its

center of mass about an external point.
Although this special property is only explained
in the relativistic quantum mechanics of
Paul M. Dirac, it plays a most-important role
already in non-relativistic quantum
mechanics, e.g., it essentially determines the
structure of atoms. In

physics, the proton (Greek
πρώτον / proton = first) is a

subatomic particle with an

electric charge of one positive

fundamental unit (1.602 × 10⁻¹⁹

coulomb), a diameter of about 1.6 to 1.7×10⁻¹⁵

m ^[1], and a
mass of 938.27231(28)

MeV/c²
(1.6726
× 10⁻²⁷ kg), 1.007 276 466 88(13)

u or about 1836 times the mass of an

electron. Protons are

spin-1/2

fermions and are composed of three

quarks^[2],
making them

baryons. Knowledge is defined (Oxford
English Dictionary) variously as (i)
expertise, and skills acquired by a person
through

experience or

education; the theoretical or practical
understanding of a subject, (ii) what is known
in a particular field or in total; facts and
information or (iii) awareness or familiarity
gained by experience of a fact or situation.
Systematic means
methodical in
procedure or plan <a
systematic approach>
<a systematic scholar>
b: marked
by thoroughness and regularity
<systematic efforts>.
Practice is the act of rehearsing
a behavior over and over, or engaging in an
activity again and again, for the purpose of
improving or mastering it, as in the phrase
"practice makes perfect". Sports teams practice
to prepare for actual games. Scientific
method refers to the body of techniques for
investigating

phenomena, acquiring new

knowledge, or correcting and integrating
previous knowledge. It is based on gathering

observable,

empirical and

measurable

evidence subject to specific principles of

reasoning.^[1]Research is a human activity based
on

intellectual investigation and is aimed at

discovering,

interpreting, and

revising human

knowledge on different aspects of the world.
Research can use the

scientific method, but need not do so.
Fundamental means
serving as an
original or generating source : primary
<a discovery fundamental
to modern computers>
b: serving
as a basis supporting existence or determining
essential structure or function : basic2
a: of
or relating to essential structure, function, or
facts : radical
<fundamental change>;
also
: of or dealing with general
principles rather than practical application
<fundamental science>
b: adhering
to

fundamentalism. Quantity
is a kind of which exists as magnitude or
multitude. It is among the basic classes of
things along with

quality,

substance,

change, and

relation. An operational definition
is a showing of something — such as a

variable,

term, or

object — in terms of the specific

process or set of

validation tests used to determine its
presence and quantity. Properties described in
this manner must be publicly accessible so that
persons other than the definer can independently
measure or test for them at will. Measurement
means

A system of measuring: measurement in miles.
The dimension, quantity, or capacity
determined by measuring: the measurements of
a room. Distance is a numerical
description of how far apart objects are at
any given moment in time. In

physics or everyday discussion, distance
may refer to a physical length, a period of
time, or an estimation based on other
criteria (e.g. "two counties over"). In

physics, acceleration is defined
as the

rate of change of

velocity, or as the second

derivative of position (with respect to
time). It is then a

vector quantity with dimension

length/time².
Greek (ελληνική
γλώσσα

IPA:

[eliniˈkʲi ˈɣlosa] or simply
ελληνικά

IPA:

[eliniˈka] — "Hellenic") has a
documented history of 3,400 years, the
longest of any single

natural language in the

Indo-European

language family. It is also one of the
earliest attested Indo-European languages,
with fragmentary records in

Mycenaean dating back to the 15th or
14th century BC, making it one of the
world's oldest recorded living languages. A
scalar is a variable that only has

magnitude, e.g. a

speed of 40 km/h. Compare it with

vector, a quantity comprising both
magnitude and

direction, e.g. a

velocity of 40km/h north. A physical

quantity is a physical

property that can be quantified. This
means it can be measured and/or calculated.
In

physics, mechanical work is the
amount of

energy transferred by a

force. Like energy, it is a

scalar quantity, with

SI units of

joules. Classical mechanics
(commonly confused with Newtonian
mechanics, which is a subfield thereof)
is used for describing the motion of
macroscopic objects, from

projectiles to parts of

machinery, as well as

astronomical objects, such as

spacecraft,

planets,

stars, and

galaxies. It produces very accurate
results within these domains, and is one of
the oldest and largest subjects in

science and

technology. Special relativity
(SR) (aka the special theory of
relativity (STR)) is the

physical theory of

measurement in

inertial frames of reference proposed in

1905 by

Albert Einstein in the paper "On
the Electrodynamics of Moving Bodies".^[1]
It generalizes

Galileo's principle of relativity — that
all

uniform motion is relative, and that
there is no absolute and well-defined state
of rest (no

privileged reference frames) — from

mechanics to all the

laws of physics, including both the laws
of mechanics and of

electrodynamics, whatever they may be.
General relativity (GR) or
General theory of relativity (GTR)
is the

geometric

theory of

gravitation published by

Albert Einstein in 1915/16.^[1]
It unifies

special relativity,

Newton's law of universal gravitation,
and the insight that gravitational

acceleration can be described by the

curvature of

space and

time, this latter being produced by the

mass-energy
and

momentum content of the matter in

spacetime. A subatomic particle
is an

elementary or

composite

particle smaller than an

atom.

Particle physics and

nuclear physics are concerned with the
study of these particles, their
interactions, and non-atomic

matter.}