Media playback is unsupported on your device Media caption Pallab Ghosh explains the significance of the visual simulation 
 
 An international team of researchers has created the most complete visual simulation of how the Universe evolved. 
 
 The computer model shows how the first galaxies formed around clumps of a mysterious, invisible substance called dark matter. 
 
 It is the first time that the Universe has been modelled so extensively and to such great resolution. 
 
 The research has been published in the journal Nature. 
 
 Now we can get to grips with how stars and galaxies form and relate it to dark matter Prof Richard Ellis, Caltech 
 
 The simulation will provide a test bed for emerging theories of what the Universe is made of and what makes it tick. 
 
 One of the world's leading authorities on galaxy formation, Professor Richard Ellis of the California Institute of Technology (Caltech) in Pasadena, described the simulation as "fabulous". 
 
 "Now we can get to grips with how stars and galaxies form and relate it to dark matter," he told BBC News. 
 
 The computer model draws on the theories of Professor Carlos Frenk of Durham University, UK, who said he was "pleased" that a computer model should come up with such a good result assuming that it began with dark matter. 
 
 "You can make stars and galaxies that look like the real thing. But it is the dark matter that is calling the shots". 
 
 Cosmologists have been creating computer models of how the Universe evolved for more than 20 years. It involves entering details of what the Universe was like shortly after the Big Bang, developing a computer program which encapsulates the main theories of cosmology and then letting the programme run. 
 
 The simulated Universe that comes out at the other end is usually a very rough approximation of what astronomers really see. 
 
 Image copyright Illustris Image caption The real Universe photographed by the Hubble telescope is on the left. On the right is what emerges from the simulation 
 
 The latest simulation, however, comes up with the Universe that is strikingly like the real one. 
 
 You can make stars and galaxies that look like the real thing. But it is the dark matter that is calling the shots Prof Carlos Frenk, Durham University 
 
 Immense computing power has been used to recreate this virtual Universe. It would take a normal laptop nearly 2,000 years to run the simulation. However, using state-of-the-art supercomputers and clever software called Arepo, researchers were able to crunch the numbers in three months. 
 
 Cosmic tree 
 
 In the beginning, it shows strands of mysterious material which cosmologists call "dark matter" sprawling across the emptiness of space like branches of a cosmic tree. As millions of years pass by, the dark matter clumps and concentrates to form seeds for the first galaxies. 
 
 Then emerges the non-dark matter, the stuff that will in time go on to make stars, planets and life emerge. 
 
 But early on there are a series of cataclysmic explosions when it gets sucked into black holes and then spat out: a chaotic period which was regulating the formation of stars and galaxies. Eventually, the simulation settles into a Universe that is similar to the one we see around us. 
 
 According to Dr Mark Vogelsberger of Massachusetts Institute of Technology (MIT), who led the research, the simulations back many of the current theories of cosmology. 
 
 "Many of the simulated galaxies agree very well with the galaxies in the real Universe. It tells us that the basic understanding of how the Universe works must be correct and complete," he said. 
 
 In particular, it backs the theory that dark matter is the scaffold on which the visible Universe is hanging. 
 
 "If you don't include dark matter (in the simulation) it will not look like the real Universe," Dr Vogelsberger told BBC News. 
 
 Image copyright Illustris Collaboration Image caption The simulation produces galaxies of different shapes and sizes that astronomers see in the real Universe 
 
 The simulation is the first to show visible matter emerging from dark matter. It will also help cosmologists learn more about another mysterious force called dark energy that is powering the continued acceleration of the Universe. 
 
 The European Space Agency (Esa) is planning to launch a spacecraft called Euclid in 2020 to measure the acceleration of the Universe. Accurate simulations, such as the one published today, will help in that search, according to Dr Joanna Dunkley, of Oxford University. 
 
 "In order to use the data from Euclid we will need to simulate what we expect to see for dark energy and compare it with what we see," she said. 
 
 Cosmologist Dr Robin Catchpole of the Institute of Astronomy in Cambridge, added a note of caution, however. 
 
 Although he hailed the simulation as "spectacular", he added, "one must not be taken in by the sheer visual beauty of the thing. You get things that look like galaxies without them being much to do with the physics of how galaxies emerged". 
 
 Follow Pallab on Twitter ||||| Astronomers using NASA's Hubble Space Telescope have discovered that the universe is expanding 5 percent to 9 percent faster than expected. 
 
 "This surprising finding may be an important clue to understanding those mysterious parts of the universe that make up 95 percent of everything and don't emit light, such as dark energy, dark matter, and dark radiation," said study leader and Nobel Laureate Adam Riess of the Space Telescope Science Institute and The Johns Hopkins University, both in Baltimore, Maryland. 
 
 The results will appear in an upcoming issue of The Astrophysical Journal. 
 
 Riess' team made the discovery by refining the universe's current expansion rate to unprecedented accuracy, reducing the uncertainty to only 2.4 percent. The team made the refinements by developing innovative techniques that improved the precision of distance measurements to faraway galaxies. 
 
 The team looked for galaxies containing both Cepheid stars and Type Ia supernovae. Cepheid stars pulsate at rates that correspond to their true brightness, which can be compared with their apparent brightness as seen from Earth to accurately determine their distance. Type Ia supernovae, another commonly used cosmic yardstick, are exploding stars that flare with the same brightness and are brilliant enough to be seen from relatively longer distances. 
 
 By measuring about 2,400 Cepheid stars in 19 galaxies and comparing the observed brightness of both types of stars, the accurately measured their true brightness and calculated distances to roughly 300 Type Ia supernovae in far-flung galaxies. 
 
 The team compared those distances with the expansion of space as measured by the stretching of light from receding galaxies. They used these two values to calculate how fast the universe expands with time, or the Hubble constant. 
 
 The improved Hubble constant value is 73.2 kilometers per second per megaparsec. (A megaparsec equals 3.26 million light-years.) The new value means the distance between cosmic objects will double in another 9.8 billion years. 
 
 This refined calibration presents a puzzle, however, because it does not quite match the expansion rate predicted for the universe from its trajectory seen shortly after the Big Bang. Measurements of the afterglow from the Big Bang by NASA's Wilkinson Microwave Anisotropy Probe (WMAP) and the European Space Agency's Planck satellite mission yield predictions which are 5 percent and 9 percent smaller for the Hubble constant, respectively. 
 
 "If we know the initial amounts of stuff in the universe, such as dark energy and dark matter, and we have the physics correct, then you can go from a measurement at the time shortly after the big bang and use that understanding to predict how fast the universe should be expanding today," said Riess. "However, if this discrepancy holds up, it appears we may not have the right understanding, and it changes how big the Hubble constant should be today." 
 
 Comparing the universe's expansion rate with WMAP, Planck, and Hubble is like building a bridge, Riess explained. On the distant shore are the cosmic microwave background observations of the early universe. On the nearby shore are the measurements made by Riess' team using Hubble. 
 
 "You start at two ends, and you expect to meet in the middle if all of your drawings are right and your measurements are right," Riess said. "But now the ends are not quite meeting in the middle and we want to know why." 
 
 There are a few possible explanations for the universe's excessive speed. One possibility is that dark energy, already known to be accelerating the universe, may be shoving galaxies away from each other with even greater -- or growing -- strength. 
 
 Another idea is that the cosmos contained a new subatomic particle in its early history that traveled close to the speed of light. Such speedy particles are collectively referred to as "dark radiation" and include previously known particles like neutrinos. More energy from additional dark radiation could be throwing off the best efforts to predict today's expansion rate from its post-big bang trajectory. 
 
 The boost in acceleration could also mean that dark matter possesses some weird, unexpected characteristics. Dark matter is the backbone of the universe upon which galaxies built themselves up into the large-scale structures seen today. 
 
 And finally, the speedier universe may be telling astronomers that Einstein's theory of gravity is incomplete. 
 
 "We know so little about the dark parts of the universe, it's important to measure how they push and pull on space over cosmic history," said Lucas Macri of Texas A&M; University in College Station, a key collaborator on the study. 
 
 The Hubble observations were made with Hubble's sharp-eyed Wide Field Camera 3 (WFC3), and were conducted by the Supernova H0 for the Equation of State (SH0ES) team, which works to refine the accuracy of the Hubble constant to a precision that allows for a better understanding of the universe's behavior. 
 
 The SH0ES Team is still using Hubble to reduce the uncertainty in the Hubble constant even more, with a goal to reach an accuracy of 1 percent. Current telescopes such as the European Space Agency's Gaia satellite, and future telescopes such as the James Webb Space Telescope (JWST), an infrared observatory, and the Wide Field Infrared Space Telescope (WFIRST), also could help astronomers make better measurements of the expansion rate. 
 
 Before Hubble was launched in 1990, the estimates of the Hubble constant varied by a factor of two. In the late 1990s the Hubble Space Telescope Key Project on the Extragalactic Distance Scale refined the value of the Hubble constant to within an error of only 10 percent, accomplishing one of the telescope's key goals. The SH0ES team has reduced the uncertainty in the Hubble constant value by 76 percent since beginning its quest in 2005. 
 
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 The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C. 
 
 For images and more information about the Hubble Constant finding and Hubble, visit: 
 
 http://hubblesite. org/ news/ 2016/ 17
– It's like "flying through the universe way faster than the speed of light and watching galaxies as they are assembling," says one of the researchers who has created a stunning visual simulation of how the universe formed. The "Illlustris" model created by an international team of researchers using supercomputers is so complex that it would take a normal laptop 2,000 years to run it, and it is believed to be the most accurate simulation of universe formation ever created, reports the Los Angeles Times. Previous simulations have resulted in universes that don't bear more than a passing resemblance to our own, but Illustris researchers say the inclusion of mysterious "dark matter" resulted in a more accurate universe—and helped confirm some current theories in cosmology. "Many of the simulated galaxies agree very well with the galaxies in the real universe. It tells us that the basic understanding of how the universe works must be correct and complete," the lead researcher tells the BBC. "If you don't include dark matter, it will not look like the real universe."