A new three-dimensional map of the Universe, containing 1.2 million galaxies, was released earlier this week. The map was created as a part of the Sloan Digital Sky Survey III, a program which aims at validating the current cosmologist theories.
The plan covers a volume of 650 cubic billion light-years, and it is the result of a decade of work. The release included a collection of scientific papers that will be published in the Monthly Notices of the Royal Astronomical Society.
One of the purposes was to measure dark energy, the force that accelerates the expansion of the Universe. Even if the scientists were set to search evidence for any unexplained phenomena, the SDSS-III explains they did not find any data contradicting the current theory of the Universe.
The Map of the Universe
The visual representation of the Universe contains millions of dots clustered together into a vast cosmic web. Each dot signals a galaxy, a bound of stars, remnants, dust, gas, and dark matter.
The dots are colored in function of the distance towards Earth, with yellow for close galaxies and purple for distant ones. Because of the time light needs to travel through space, the map shows galaxies 6 billion years into the past.
The structure of the Universe as we can see it now was set in a split of a second after the Big Bang.
However, the map takes into consideration only the observed galaxies, those that had been detected through measurements and space observations. Experts estimate that the Universe may contain as many as 100 billion galaxies in total.
The scientists used the map to measure the void between galaxies to set the quantity of dark energy and dark matter existing in the Universe. They also tried to find out what were the effects of the dark energy in the expansion of the Universe.
The Research Behind the Map
The authors of the two studies published this week say that their dark matter measurements show the Universe is expanding at a very slow rate, with a 20% advance in the last seven billion years.
The scientists managed to create a comprehensive model of the Universe after the Big Bang, which led them to a validation of the standard cosmology theories.
Thus, it seems that galaxies move towards areas that have more matter, an effect of the gravity force.
The amount of the infall respects the theory of general relativity, which makes the researchers believe that the expansion rate is indeed driven by dark energy and other large-scale cosmic phenomena.
The Sloan Digital Sky Survey performs massive spectroscopic observations of the distant universe. Up until now, the SDSS managed to detect the baryon acoustic peak inside galaxies’ clusters; it created Milky Way maps, discovered distant quasars, and cool brown dwarfs.
Image Source: Wikipedia