September 24, 2012
Algorithm Charts Dynamics Of Universe
Lee Rannals for redOrbit.com - Your Universe Online
Astronomers have developed an algorithm that is able to chart and explain accurately the structure and dynamics of the universe.
The team developed a new algorithm based on artificial intelligence which provides results that are close to the observed distribution of motion and galaxies.
It has been hard for astronomers to explain the distribution of galaxies. Five percent of the universe is made of normal matter, making up the stars, planets, dust and gas, and 23 percent is made up of invisible dark matter.
Seventy-two percent of the universe is made up of a mysterious "dark energy" that exerts a gravitational pull and is thought to be responsible for accelerating the expansion of the universe.
These three constituents are part of the Lambda Cold Dark Matter (LCDM) model for the universe.
Astronomers are able to reconcile this motion with that predicted by the distribution of matter around us, and its associated gravitational force. However, this is difficult to do because scientists first need to map the dark matter in the same region.
"Finding the dark matter distribution corresponding to a galaxy catalogue is like trying to make a geographical map of Europe from a satellite image during the night that only shows the light coming from dense populated areas," Francisco Kitaura of the Leibniz Institute for Astrophysics in Potsdam, who led the team, said in a press statement.
The astronomers developed the algorithm to solve the problem. It starts with the fluctuations in the density of the universe seen in Big Bang heat, then models the way matter collapses in today's galaxies.
"Our precise calculations show that the direction of motion and 80% of the speed of the galaxies that make up the Local Group can be explained by the gravitational forces that arise from matter up to 370 million light years away," Kitaura said. "In comparison the Andromeda Galaxy, the largest member of the Local Group, is a mere 2.5 million light years distant so we are seeing how the distribution of matter at great distances affects galaxies much closer to home."
He said the team's results agree with predictions of the LCDM model as well.
"To explain the rest of the 20% of the speed, we need to consider the influence of matter up to about 460 million light years away, but at the moment the data are less reliable at such a large distance," he said. 'Despite this caveat, our model is a big step forward. With the help of AI, we can now model the universe around us with unprecedented accuracy and study how the largest structures in the cosmos came into being."
The team published their findings in the journal Monthly Notices of the Royal Astronomical Society.