**Conservation of Energy**

Energy is subject to the **law of conservation of energy**. According to this law, energy can neither be created (produced) nor destroyed by itself. It can only be transformed.

Most kinds of energy (with gravitational energy being a notable exception) are subject to strict local conservation laws as well. In this case, energy can only be exchanged between adjacent regions of space, and all observers agree as to the volumetric density of energy in any given space. There is also a global law of conservation of energy, stating that the total energy of the universe cannot change; this is a corollary of the local law, but not vice versa. Conservation of energy is the mathematical consequence of translational symmetry of time (that is, the indistinguishability of time intervals taken at different time) - see Noether's theorem.

According to Conservation of energy the total inflow of energy into a system must equal the total outflow of energy from the system, plus the change in the energy contained within the system.

This law is a fundamental principle of physics. It follows from the translational symmetry of time, a property of most phenomena below the cosmic scale that makes them independent of their locations on the time coordinate. Put differently, yesterday, today, and tomorrow are physically indistinguishable.

This is because energy is the quantity which is canonical conjugate to time. This mathematical entanglement of energy and time also results in the uncertainty principle - it is impossible to define the exact amount of energy during any definite time interval. The uncertainty principle should not be confused with energy conservation - rather it provides mathematical limits to which energy can in principle be defined and measured.

In quantum mechanics energy is expressed using the Hamiltonian operator. On any time scales, the uncertainty in the energy is by

which is similar in form to the Heisenberg uncertainty principle (but not really mathematically equivalent thereto, since *H* and *t* are not dynamically conjugate variables, neither in classical nor in quantum mechanics).

In particle physics, this inequality permits a qualitative understanding of virtual particles which carry momentum, exchange by which and with real particles, is responsible for the creation of all known fundamental forces (more accurately known as fundamental interactions). Virtual photons (which are simply lowest quantum mechanical energy state of photons) are also responsible for electrostatic interaction between electric charges (which results in Coulomb law), for spontaneous radiative decay of exited atomic and nuclear states, for the Casimir force, for van der Waals bond forces and some other observable phenomena.

Read more about this topic: Energy

### Other articles related to "conservation of energy, energy, of energy, conservation of, conservation":

**Conservation of Energy**

... The First Law of Thermodynamics is the statement of the conservation of energy ... Under specific conditions, the operation of a Centrifugal compressor is considered a reversible process ...

**Conservation Of Energy**- Mechanics - Quantum Theory

... In quantum mechanics,

**energy**of a quantum system is described by a self-adjoint (Hermite) operator called Hamiltonian, which acts on the Hilbert space (or a space of wave functions ) of the system ... Thus the expectation value

**of energy**is also time independent ... The local

**energy**conservation in quantum field theory is ensured by the quantum Noether's theorem for

**energy**-momentum tensor operator ...

**Conservation of Energy**

... In 1918 it was proved that the law of

**conservation of energy**is the direct mathematical consequence of the translational symmetry of the quantity conjugate to

**energy**... That is,

**energy**is conserved because the laws of physics do not distinguish between different moments of time (see Noether's theorem) ... and Nobel Laureate, said this about the concept

**of energy**There is a fact, or if you wish, a law, governing natural phenomena that are known to date ...

... cristata are covered under the Agreement on the

**Conservation of**African-Eurasian Migratory Waterbirds (AEWA) ... Parties to the Agreement are required to engage in a wide range of

**conservation**strategies described in a detailed action plan ... plan is intended to address key issues such as species and habitat

**conservation**, management of human activities, research, education, and implementation ...

... Other major

**conservation**centres in Indonesia include those at Tanjung Puting National Park and Sebangau National Park in Central Kalimantan, Kutai in ... In Malaysia,

**conservation**areas include Semenggoh Wildlife Centre in Sarawak and Matang Wildlife Centre also in Sarawak, and the Sepilok Orang Utan Sanctuary near Sandakan in Sabah ... Major

**conservation**centres that are headquartered outside of the orangutan's home countries include Orangutan Foundation International, which was founded by BirutÄ— Galdikas, and the ...

### Famous quotes containing the words conservation of, energy and/or conservation:

“A country grows in history not only because of the heroism of its troops on the field of battle, it grows also when it turns to justice and to right for the *conservation of* its interests.”

—Aristide Briand (1862–1932)

“Crime is naught but misdirected *energy*. So long as every institution of today, economic, political, social, and moral, conspires to misdirect human *energy* into wrong channels; so long as most people are out of place doing the things they hate to do, living a life they loathe to live, crime will be inevitable.”

—Emma Goldman (1869–1940)

“The putting into force of laws which shall secure the *conservation* of our resources, as far as they may be within the jurisdiction of the Federal Government, including the more important work of saving and restoring our forests and the great improvement of waterways, are all proper government functions which must involve large expenditure if properly performed.”

—William Howard Taft (1857–1930)