2007-03-29 23:27:10 · 5 answers · asked by haaj ghafoor 1 in Science & Mathematics ➔ Astronomy & Space
(m)
In physical cosmology, dark energy is a hypothetical form of energy that permeates all of space and has strong negative pressure.According to the Theory of Relativity, the effect of such a negative pressure is qualitatively similar to a force acting in opposition to gravity at large scales. Invoking such an effect is currently the most popular method for explaining recent observations that the universe appears to be expanding at an accelerating rate, as well as accounting for a significant portion of the missing mass in the universe.
Two proposed forms for dark energy are the cosmological constant, a constant energy density filling space homogeneously, and quintessence, a dynamic field whose energy density can vary in time and space. Distinguishing between the alternatives requires high-precision measurements of the expansion of the universe to understand how the speed of the expansion changes over time. The rate of expansion is parameterized by the cosmological equation of state. Measuring the equation of state of dark energy is one of the biggest efforts in observational cosmology today.
Adding a cosmological constant to the standard theory of cosmology (i.e. the FLRW metric) has led to a model for cosmology known as the Lambda-CDM model. This model agrees closely with established cosmological observations.
2007-03-29 23:33:48 · answer #1 · answered by mallimalar_2000 7 · 3⤊ 0⤋
dark energy is a theoretical entity,Einstein had included an "anti-gravity" effect in his theory of general relativity, in his so-called "cosmological constant". But Einstein himself, and later many other astronomers, came to regard this as a kind of mathematical contrivance that had little relationship to the real universe. By the 1990s no one expected that the effect would turn out to be real.
Still, anti-gravity isnt the right way to describe dark energy.It does exactly what general relativity says it should do, if it has negative pressure.
the strongest evidence for the existence of dark energy is the fact that the universe is not only expanding but the expansion is accelerating, therefore there must be some dark enerygy we cannot "see" that is causing this acceleration. its source is the universe itself and its measurment its proof and its impact is the expansion of the universe.
i hope this helps!!!!!
2007-03-30 01:08:57 · answer #2 · answered by Tharu 3 · 1⤊ 0⤋
Dark energy is always out there. We draw it to us when we have negative thoughts. If you focus on the things that have been wrong in your life this opens the path of yuckiness around us. Its kind of like witchcraft. There is the good side and the bad side. When you open yourself up to one you basically have to channel only good karma. Think and believe in all good and good is what you will receive.
2007-03-29 23:43:08 · answer #3 · answered by Anonymous · 0⤊ 2⤋
A term made up to provide a placeholder for an unexplainable set of behaviors that have been observed.
2007-03-30 21:44:27 · answer #4 · answered by Fred 7 · 0⤊ 0⤋
http://en.wikipedia.org/wiki/Dark_energy
2007-03-30 00:22:15 · answer #5 · answered by neutron 3 · 0⤊ 0⤋