Alrrededor of dark energy

A very exciting for those interested in inquiring about everything the universe contains. It is noted that dark energy is Einstein's cosmological constant or, in other words, that 'nothing weighs something', "said Alexey Vikhlinin of the Smithsonian Astrophysical Observatory (Cambridge, USA), who led the study . The dark energy would be the vacuum energy, like physicists viewed as a very light particle field in an unstable state, basically a waste of the state of the universe just after the Big Bang. If they are right, when all these particles become subject, within a few billion years, the universe will eventually accelerate.

espacioprofundo.com ar. reminds us that dark energy was discovered by two teams of astronomers working in Australia and the U.S., making searches for distant supernovae to determine the distance (can be based on the observation of a supernova know the distance to which it is located. A certain type of supernova is the S1a with very precise mechanism which exploits and exploit always makes the same brightness 'real' (absolute magnitude), this means that it can take as a source of distance, and Of course, if the distance to the supernova know the distance to the galaxy that contains it.)

The fact that on Wikipedia it gives us, in physical cosmology, dark energy is a hypothetical form of matter or energy that would be present in all space, producing a negative pressure which tends to increase the accelerating expansion of the Universe resulting in a repulsive gravitational force. Assuming the existence of dark energy is the most frequent to explain recent observations that the universe appears to be expanding with positive acceleration. In the standard model of cosmology, dark energy currently accounts for almost three quarters of the total mass-energy of the universe.

Two possible forms of dark energy are the cosmological constant, a constant energy density filling space homogeneously, and quintessence scalar fields: Dynamic field whose energy density can vary in time and space. In fact, the contributions of scalar fields which are constant in space are usually also included in the cosmological constant. It is believed that the cosmological constant arises from the vacuum energy. Scalar fields that change over space are difficult to distinguish from a cosmological constant because changes can be extremely slow.

To discriminate between these very precise measurements are needed for the expansion of the universe, to see if the expansion rate changes over time. The rate of expansion is parameterized by the equation of state. Measuring the equation of state of dark energy is one of the biggest research challenges current physical cosmology

We also point out that in 1998, observations of type 1a supernovae far away, made by the Supernova Cosmology Project at Lawrence Berkeley National Laboratory and the High-z Supernova Search Team, suggested that the Universe's expansion was accelerating . Since then, this acceleration has been confirmed by several independent sources: measurements of the cosmic microwave background, gravitational lensing, primordial nucleosynthesis of light elements and large-scale structure of Universe, as well as improved measurements of supernovae have been consistent with the Lambda-CDM model.

We are told also that type 1a supernovae provide the main direct evidence of the existence of dark energy. Because Hubble's Law, all seemingly distant galaxies are moving away from the Milky Way, showing a redshift in the light spectrum due to the Doppler effect. The measurement of the scale factor at the time the light was emitted from an object is easily obtained by measuring the redshift of the object in recession. This shift indicates the age of a distant object proportionally, but not absolute. The existence of dark energy, in whatever form is necessary to reconcile the geometry of space as the total amount of matter in the Universe. The measurements of the cosmic microwave background most recent, carried out by the WMAP satellite, indicate that the universe is very close to being flat. For the shape of the Universe is flat, the density of mass / energy of the universe must be equal to a certain critical density. Further observations of the cosmic microwave background and the proportion of elements formed in the Big Bang have put a limit to the amount of baryonic matter and dark matter that can exist in the universe, which has only 30% of the critical density.

This implies the existence of an additional form of energy account for 70% of the mass remaining power. These studies indicate that 73% of the mass of the universe consists of dark energy, 23% is dark matter (cold dark matter and hot dark matter) and 4% baryonic matter. The theory of large-scale structure of the universe, which determines the formation of structures in the Universe (stars, quasars, galaxies and galaxy clusters) also suggests that the density of matter in the universe is only 30% of the critical density .

On the other hand, says www.neoteo.com, which in a few million years will not be able to see galaxies in the space around us. At least that is what emerges from the new and exciting discoveries made by NASA regarding the existence of "dark energy". This energy is accelerating the expansion of the universe and makes fleeing neighboring galaxies, increasingly fast around us. Just as the so-called "dark matter" was the favorite resource for scientists to explain why the universe could be closed, are now speculating about the nature of a mysterious dark energy that could explain the effect of acceleration.

This theory has received a major boost from the results of some recent observations with the orbiting telescope Chandra X-Ray, who photographed some distant galaxy clusters. Since light takes to reach a time proportional to the distance between galaxies of us, the farther away the object observed, "oldest" is the picture we get of him. Astronomers observing the hot gas through X-ray clusters of recent (near) and old, with more than 5,000 million years of existence (more distant) have seen how they have changed the number and mass of clusters of galaxies along the tiempo.La first conclusion that can be obtained from the study is that Einstein was right when he said finally that general relativity works on large scales and the need for a cosmological constant into his equations (but then discarded). "Combining all the data, we have evidence that dark energy is Einstein's cosmological constant or, in other words, that 'nothing weighs something'," said Alexey Vikhlinin of the Smithsonian Astrophysical Observatory (Cambridge, USA. UU.), who led the study. Dark energy would be the vacuum energy, like physicists viewed as a very light particle field in an unstable state, basically a waste of the state of the universe just after the Big Bang.

If they are right, when all these matter particles become, within a few billion years, the universe will eventually accelerate.

Ultimately as indicated solociencia.com, astrophysicists, in recent years have found evidence of a force they call dark energy in observations from the farthest reaches of the universe, billions of light years away.

Do not forget that in 1929 the astronomer Edwin Hubble showed that galaxies are receding from each other, which supported the theory that the universe has expanded since the Big Bang. In 1999, cosmologists announced a rare evidence of force, called dark energy, actually causing the accelerated expansion of universo.Sin However, the expansion is slower than it could be due to the force of gravity between the galaxies. As the battle between the pull of gravity and the repulsive force of dark energy is developed, cosmologists ponder whether the expansion will continue forever or whether the universe will collapse in a "Big Crunch".

According to the latest measurements, the Universe is 5-6% of baryonic matter, 30% dark matter and dark energy 65%.