Defective data: Researchers have now analysed a cold spot in the map of the cosmic microwave background and determined it has properties expected from a defect or 'texture'. This image shows a random collection of textures taken from high-resolution, supercomputer simulations. Red indicates a positive twist in the topological charge density and blue a negative twist.
Credit: V. Travieso and N. Turok
SYDNEY: A cold spot in the cosmic background radiation (CMB), created just after the Big Bang, may be by a defect. If confirmed, it could shed light on how particles reacted as the early universe formed.
"The cosmic microwave background is the most ancient image we have of the universe and therefore it's one of the most valuable tools to understand the universe's origins. If this spot is a texture, it would allow us to discriminate among different theories that have been proposed for how the universe evolved," said astrophysicist Marcos Cruz from the Institute of Physics Cantabria in Spain.
Frozen record
The CMB radiation filled the universe during the period of expansion following the Big Bang, and forms a frozen record of the universe's first moments. There are variations in the temperature of the radiation, which particle physicists have long theorised may be defects created by the cooling of the hot, early universe.
Since 2001, scientists have been able to examine the CMB with unprecedented clarity using the Microwave Anisotropy Probe, a NASA satellite mapping the background radiation. Using this data, researchers led by Cruz, have now examined one of the larger and more striking of the cold spots, and modelled its possible evolution using statistics and computer simulations.
The model that best fits the data for the cold spot's existence is that it is a cosmic 'texture' – a defect that formed as the early matter of the universe changed phase, much the same way that tiny defects form in an ice-cube as water changes phase from liquid to solid.
"Phase transition remnants"
If the presence of the cosmic texture is confirmed, it will provide a unique window into high energy physics and how the early universe evolved, report the scientists today in the U.S. journal Science.
"Cosmic defects are hypothetical remnants of symmetry-breaking phase transitions in the early universe, predicted by certain unified theories of elementary particle physics," the researchers write.
Mathematical physicist and study co-author, Neil Turok, from the UK's University of Cambridge describes cosmic texture as "a three-dimensional object like a blob of energy, but within the blob the energy fields making up the texture are twisted up."
Turok says the researchers are not certain from the initial study that this is a texture. "But what makes this so interesting is that ... there are a number of follow-up tests which can be made with future data. It's a very testable hypothesis and we will know the answer within the next decade."
