In cosmology,
dark energy is a hypothetical form of
energy which
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.
As NASA reports indicate, 70 percent or more of the universe consists
of
dark energy, about which we know next to nothing.
At the beginning of March, 2006 the satellite of China National Space
Administration, DARKSTAR started operations, observing in neutrino the
solar corona.
It results a sensational information that our system also contains
dark energy. This substance is located within the solar surface.
We have placed above cosmological information into our
screensaver and you
can view allocation of
dark matter in our Solar system!
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