Everything about Subatomic totally explained
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.
Subatomic particles include the atomic constituents
electrons,
protons, and
neutrons. Protons and neutrons are
composite particles, consisting of
quarks. A proton contains two up quarks and one down quark, while a neutron consists of one up quark and two down quarks; the quarks are held together in the nucleus by
gluons. There are six different types of quark in all ('up', 'down', 'bottom', 'top', 'strange', and 'charm'), as well as other particles including
photons and
neutrinos which are produced copiously in the
sun. Most of the particles that have been discovered are encountered in
cosmic rays interacting with matter and are produced by scattering processes in
particle accelerators. There are dozens of subatomic particles.
Introduction to particles
In
particle physics, the conceptual idea of a
particle is one of several concepts inherited from
classical physics, the world we experience, that are used to describe how
matter and
energy behave at the molecular scales of
quantum mechanics.
As physicists use the term, the meaning of the word "particle" is one which understands how particles are radically different at the quantum-level, and rather different from the common understanding of the term.
The idea of a
particle is one which had to undergo serious rethinking in light of experiments which showed that the smallest particles (of light) could behave just like
waves.
The difference is indeed vast, and required the new concept of
wave-particle duality to state that quantum-scale "particles" are understood to behave in a way which resembles both particles and waves.
Another new concept, the
uncertainty principle, meant that analyzing particles at these scales required a
statistical approach.
All of these factors combined such that the very notion of a discrete "particle" has been ultimately replaced by the concept of something like wave-packet of an uncertain boundary, whose properties are only known as probabilities, and whose interactions with other "particles" remain largely a mystery, even 80 years after quantum mechanics was established.
Energy
Energy and matter we've studied from
Einstein's hypotheses are
analogous: matter can be austerely denoted in terms of energy. Thus, we've only discovered two mechanisms in which energy can be transferred. These are
particles and
waves. For example, light can be expressed as both
particles and
waves. This
paradox is known as the Duality Paradox.
.
Through the work of Albert Einstein, Louis de Broglie and many others, current scientific theory holds that all particles also have a wave nature.[1] This phenomenon has been verified not only for elementary particles, but also for compound particles like atoms and even molecules. In fact, according to traditional formulations of non-relativistic quantum mechanics, wave–particle duality applies to all objects, even macroscopic ones; we can't detect wave properties of macroscopic objects due to their small wavelengths.[2]
Interactions between particles have been scrutinized for many centuries, and a few simple laws underpin how particles proceed in collisions and interactions. The most angelic of these are the
conservation of energy and momentum which facilitate us to elucidate calculations between particle interactions on scales of magnitude which diverge between
planets and
quarks. These are the prerequisite basics of
Newtonian mechanics, a series of statements and equations in
Philosophiae Naturalis Principia Mathematica originally published in
1687.
Dividing an atom
The study of
electrochemistry led
G. Johnstone Stoney to postulate the existence of the
electron (denoted
e−) in
1874 as a constituent of the atom. It was observed in
1897 by
J. J. Thomson. Subsequent speculation about the structure of atoms was severely constrained by the
1907 experiment of
Ernest Rutherford which showed that the atom was mostly empty space, and almost all its mass was concentrated into the (relatively) tiny
atomic nucleus. The development of the
quantum theory led to the understanding of
chemistry in terms of the arrangement of electrons in the mostly empty volume of atoms.
Protons (
p+) were known to be the nucleus of the
hydrogen atom.
Neutrons (
n) were postulated by Rutherford and discovered by
James Chadwick in
1932. The word
nucleon denotes both the neutron and the proton.
Electrons, which are negatively charged, have a mass of 1/1836 of a
hydrogen atom, the remainder of the atom's mass coming from the positively charged
proton. The
atomic number of an element counts the number of protons. Neutrons are neutral particles with a mass almost equal to that of the proton. Different isotopes of the same nucleus contain the same number of protons but differing numbers of neutrons. The
mass number of a nucleus counts the total number of nucleons.
Chemistry concerns itself with the arrangement of electrons in atoms and molecules, and
nuclear physics with the arrangement of protons and neutrons in a nucleus. The study of subatomic particles, atoms and molecules, their structure and interactions, involves
quantum mechanics and
quantum field theory (when dealing with processes that change the number of particles). The study of subatomic particles per se is called
particle physics. Since many particles need to be created in high energy
particle accelerators or
cosmic rays, sometimes particle physics is also called
high energy physics.
History
J. J. Thomson discovered
electrons in
1897. In
1905 Albert Einstein demonstrated the physical reality of the
photons which were postulated by
Max Planck in order to solve the problem of
black body radiation in thermodynamics.
Ernest Rutherford discovered in
1907 in the
gold foil experiment that the atom is mainly empty space, and that it contains a heavy but small
atomic nucleus. The early successes of the
quantum theory involved explaining properties of
atoms in terms of their
electronic structure. The
proton was soon identified as the nucleus of hydrogen. The
neutron was postulated by Rutherford following his discovery of the nucleus, but was discovered by
James Chadwick much later, in
1932.
Neutrinos were postulated in
1931 by
Wolfgang Pauli (and named by
Enrico Fermi) to be produced in
beta decays (the
weak interaction) of neutrons, but were not discovered till
1956.
Pions were postulated by
Hideki Yukawa as mediators of the
strong force which binds the nucleus together. The
muon was discovered in
1936 by
Carl D. Anderson, and initially mistaken for the
pion. In the
1950s the first
kaons were discovered in
cosmic rays.
The development of new
particle accelerators and
particle detectors in the
1950s led to the discovery of a huge variety of
hadrons, prompting
Wolfgang Pauli's remark: "Had I foreseen this, I'd have gone into botany". The classification of hadrons through the
quark model in
1961 was the beginning of the golden age of modern particle physics, which culminated in the completion of the unified theory called the
standard model in the
1970s. The discovery of the weak gauge bosons through the
1980s, and the verification of their properties through the
1990s is considered to be an age of consolidation in particle physics. Among the standard model particles the existence of the
Higgs boson remains to be verified— this is seen as the primary physics goal of the accelerator called the
Large Hadron Collider in
CERN. All currently known particles fit into the standard model.
Visualisation
In 2000 a group of scientists from
University of Michigan joined forces with designer Jan-Henrik Andersen with a goal "to nurture a future consensus on how to visually represent subatomic particle energy and matter". They resulted in a project
"Sized Matter: perception of the extreme unseen"
where series of particles such as
photon and some
atomic events were depicted possibly closely to what is 'natural'.
Further Information
Get more info on 'Subatomic'.
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