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The universe incredible acceleration of expansion! Dark energy finally found

via:驱动之家     time:2018/1/30 9:20:48     readed:4854

The latest astronomical observations show that,The universe is incredible to accelerate the expansion.

Since its discovery in 1998, the discovery of the Nobel Prize in Physics, which was discovered in 1998, exploring the root causes of this strange phenomenon has been one of the most significant research topics for physicists and astronomers all over the world.

According to the latest research,The current universe contains only about 4% of common matter and 23% of dark matter, while the remaining 73% of the energy components are provided by the mysterious dark energy.

Although the nature of dark energy has not yet been revealed, astronomical observations show that dark energy fills the universe and there is no known interaction between dark energy and other matter except gravitation.

Dark energy density is very low (about 10-27kg / m3), but it is the pushing behind the expansion of the universe!(This refers to the generalized dark energy, which includes not only the energy components with negative pressure, but also the cosmoscopic correction gravity effect.)

Dark energy is like a ghost in the deep universe (several typical dark energy models are named as ghosts, ghosts, elves, etc.) that can not be seen or touched, but it influences and even determines the evolution and destiny of the universe. It can change the geometric properties of space-time, but also dominate the galaxy in the universe distribution and evolution.


Quasar art drawing, from Wikipedia, https://en.wikipedia.org/wiki/Quasar

Large-scale galaxy patrolling is a weapon for studying dark energy. It can detect large-scale galaxy galaxy by large-scale "population census" and then analyze the three-dimensional distribution of galaxies, reconstruct the expansion history of the universe and the growth rate of the large-scale structure of the universe, The nature of dark energy.

Currently the largest galaxy in the world is on tour"Expanding Bass Sonar Surveys" of the Sloan Phase IV (SDSS-IV) (eBOSS; 2014-2020).

The project relies on a 2.5-meter optical telescope located in New Mexico, the United States, to observe a variety of types of astral stars from the Earth billions to tens of billions of light-years. By analyzing the three-dimensional distribution of these samples, we can extract two core information closely related to the nature of dark energy:Baryon Sonic Wave (BAO) and Redshift Distortion (RSD) signals.


SDSS 2.5 meter telescope in New Mexico, USA

Basso Acoustic Waves (BAO) is a measure of the geometry of the universe and can be used to measure the expansion of the universe by measuring its agglomeration. It is a unique three-dimensional mass formation of celestial bodies formed by the interaction of photons and baryons in the early universe.

Redshift Distortion (RSD) is another special three-dimensional formation of celestial bodies that can measure the rate of mass-density disturbance growth in the universe. It is due to the celestial bodies under the action of local gravity caused by an apparent anisotropy.

In the study of dark energy, BAO and RSD complement each other. Based on these BAO and RSD data, we can understand the nature of dark energy through the "growth" history of the universe.

The eBOSS Sky Survey International Cooperation Group successfully measured baryonic sonic oscillations for the first time in 2017 using distant quasars, which are super-massive black holes.Recently, eBOSS International Cooperation Group announced that for the first time the use of quasars successfully measured the universe chromatographic redshift distortion signal(Zhao et al., 2018; arXiv: https: // arxiv.org/abs/1801.03043).

Scientists use a new approach to simultaneously measure BAO and RSD signals at key moments in many cosmic evolutions.

This is actually a CT scan of the universe. This successful attempt captured precious information about the evolutionary history of the universe.

Based on this measurement, the eBOSS team announced that the confidence level of dark energy is 7.4 standard deviation! This means that the currently observed dark energy signal is 7.4 times its statistical error, whereas according to the standard of physics, signals with a standard deviation of 5 normally can be regarded as "discovering" new physical phenomena.

Therefore, this result is a strong observation of the existence of dark energy. This is also the current dark energy observation limit based on the highest accuracy obtained from galactic surveys.

In the next 5-10 years, the eBOSS team and future large-scale galaxy surveying projects such as DESI and PFS will conduct full-scale CT scans of the universe with greater precision in the universe, accurate measurement of the equation of state for dark energy, etc. Key cosmological parameters reveal the mysteries of the accelerating expansion of the universe.

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