In recent days, two groups of researchers have published their cosmic maps. The VIPERS project used the VIMOS spectrograph installed on ESO’s VLT (Very Large Telescope) to examine 90,000 galaxies and create a wide and highly accurate three-dimensional map of the distant universe. The Pan-STARRS project used the telescope at Haleakala, Hawaii, to obtain repeated images of three-quarters of the visible sky and create a map of billions of space objects.
The VIPERS (VIMOS Public Extragalactic Survey) project is coordinated by researchers of Italian INAF and for eight years observed 90,000 galaxies reconstructing their spatial distribution and their physical properties. The research observed galaxies in deep space and some of them are very old, with ages up to 9 billion years. There’s a specific interest in the universe when it was relatively young.
The observed galaxies are grouped in large filamentous structures that connect the galaxy clusters surrounding large voids. Mapping them can provide useful data to understand how these structures have developed over time thanks to the comparison with current maps of the universe, for example those of another large survey called SDSS (Sloan Digital Sky Survey). What was called a cosmic web is considered to be the result of small perturbations already existing in the early universe that were amplified by gravity.
Of the galaxies observed, information was gathered regarding their brightness ranging from infrared to ultraviolet, their intrinsic colors, the total mass of their stars, the speed of creation of other stars, their shape and internal structure. All this allowed to create a map that combines large volume and small-scale details of the structures.
This huge map will not only be useful as an aid in astronomical observations but also for a number of cosmological research. For example, reconstructing the movements of galaxies on very long periods will allow to conduct other tests of Albert Einstein’s theory of general relativity on a truly massive scale. We’re talking about movements for which the existence of dark energy was theorized and reconstructing them with precision will help figure out whether it really exists and perhaps provide clues to its nature.
The map of the Pan-STARRS (Panoramic Survey Telescope And Rapid Response System) project is more general, since it includes about 3 billion space objects including stars, galaxies, and others ranging from objects in the Kuiper Belt to cosmic dust clouds. The data were collected between May 2010 and March 2014 in a series of surveys called Pan-STARRS 1 obtaining a wealth of information that has been estimated at a total of about a hundred times that contained in the entire Wikipedia.
The Pan-STARRS project included a series of objects in the solar system, which means in our neighborhood in astronomical terms. One of the surveys was devoted to NEO type asteroids, potentially dangerous for the Earth. Its success led to a collaboration with NASA, which in recent years has been increasingly active in the mapping of those asteroids.
These two projects created different cosmic maps with different purposes but in both cases there are advances in our knowledge of the universe, near and distant, and its evolution. The maps that were created will also be useful in the coming years for a number of new research.