Dark flow

As Dark Flow ( Dark River ) a possible pattern in the proper motion of galaxy clusters is called.

Theoretical background

Nasa probe WMAP ( Wilkinson Microwave Anisotropy Probe ) measures fluctuations in the cosmic background radiation in the microwave range, which have emerged during the Big Bang. The movement of clusters of galaxies, the cosmic background radiation is altered, resulting in their direction and speed can be calculated.

After the usual assumptions of cosmology, the proper motions of clusters of galaxies should be randomly distributed relative to the cosmic background radiation in all directions.

Observation and discovery

At the Goddard Space Flight Center of NASA, the working group led by Alexander Kashlinsky has analyzed the WMAP data. The analysis of the three-year data revealed using the Sunjajew - Seldowitsch effect evidence of a surprisingly coherent flow of galaxy clusters, the speed of the movement increases with the distance. Such galaxies current can only be caused by a strong attraction for which is known but not a cause.

In 2010, the five-year WMAP data were analyzed in a further study. Thereafter, the number of the " dark flow " of galaxies involved doubled from 700 to 1400th The direction of motion of the clusters in each of the four segments shows some deviations, but all segments exhibit a remarkable agreement on.

"We detect motion along this axis, but right now our data can not state as ' strongly as we'd like Whether the clusters are coming or going"

Explanation

The authors of the study suggested that the movement is a remnant of the influence of today no longer visible regions of the universe of cosmic inflation.

Criticism

The astrophysicist Edward L. Wright published arguments for inaccuracy of the study on which the authors responded immediately. Ryan Keisler published in 2009 a study by the dark river is not a physical phenomenon, because in the study, the primary anisotropy of the cosmic background radiation was not considered.

After the Goddard Space Center, it may be an effect of a neighboring universe or a space-time region that is fundamentally different from the observable universe. The data of over 1000 galaxy clusters have been measured up to a distance of three billion light years. After Kashlinsky these measurements are not a statistical accident.

"At this point we do not have enough information to see what it is, or to constrain it. We can only say with certainty did somewhere very far away the world is very different than what we see locally. Whether it's ' another universe ' or a different fabric of space -time we do not know. "

In the year 2011 557 supernovae have been studied from the Union 2 dataset in a study. Thereafter, these objects show no synchronous movement, but their behavior is consistent with the Lambda -CDM model match. Whether there is indeed the Dark River, the data from the Planck satellite of the European Space Agency are perhaps 2012 show.