Talk:Cosmic objects
Stars
Galaxies
Clusters of galaxies
Clusters dimensions https://www.sciencedaily.com/releases/2018/04/180424093711.htm Uncovering the secret law of the evolution of galaxy clusters
The Cosmic Web
The peculiar velocities of galaxies near the Local Group. Libeskind & Tully, (C) Scientific American.
The Local Universe is shown here as a section of the super galactic plane. Both the density (color) and the corresponding velocity field (flow lines) are Wiener Filter reconstructions obtained from the CosmicFlow-2 radial peculiar velocity catalogue, which recover the observed structure in local cosmic neighborhood remarkably well (Libeskind et al 2015).
Unlike ordinary matter, dark matter does not emit or absorb light--or any other type of electromagnetic radiation. Consequently, dark matter cannot be observed directly using a telescope or any other astronomical instrument that has been developed by humans. If dark matter has these strange properties, how do we know that it exists in the first place? Like ordinary matter, dark matter interacts gravitationally with ordinary matter and radiation. Astronomers study the distribution of dark matter through observing its gravitational effects on ordinary matter in its vicinity and through its gravitational lensing effects on background radiation. The background image shows the bullet cluster, a famous example where the visible matter does not follow the mass distribution. Combining all the available evidence, dark matter represents about 83% of the matter content of the universe. Read more about dark matter on this web page. Let us know your questions and comments on the message board.
http://www.skyandtelescope.com/astronomy-news/featured-image-the-cosmic-velocity-web/
