The cosmic microwave background provides a picture of the universe as it was some 400,000 years after the big bang. By this time the universe had cooled down enough for atoms to form, which meant that there were no longer any free electrons to scatter the photons produced in the early universe. Any variations or anisotropy in the temrperature of the background radiation therefore reflect variations in the density of the universe at this time.
These temperature fluctuations can be expressed as a sum of spherical harmonics, and astrophysicists plot the relative strength of these harmonics as a function of angle. The height and positions of the peaks in this so-called 'power spectrum' are related to basic astrophysical properties of the universe.
"Our work really addresses this ancient question of whether the universe is finite or infinite," team member Jeff Weeks, a freelance mathematician based in New york, told PhysicsWeb. "The exciting point is that this is no longer pure speculation - we now have real data."
The team says that its result, if confirmed, will have implications for theories and models of quantum gravity, inflation and the big bang itself. However, the model needs to be tested further by studying the microwave background at larger angles using more data from WMAP and the Planck Surveyor, which is due to be launched later this decade.
About the author:Belle Dume is science Writer at PhysicsWeb
Scientists suggest that the geometric shape of the Dodecahedron corresponds
to the universe.
The dodecahedron has 12 faces and 20 vertices and is bounded by 12 equilateral pentagons.
The number of faces is 12, the number of edges is 30, the number of vertices is 20.
Living in a dodecahedral universe (Editorial:September 2005)
Welcome to the strange world of cosmic topology.
It is not just Physics World that looks different this month - the universe might well have changed its appearance too. If Jean-Pierre Luminet and co-workers are correct, space is not, as we previously thought, flat and infinite. Rather, we could live in a universe that is shaped like a football - a Poincare dodecahedron to be precise - and resembles a video game in certain ways. We have been here before. Einstein thought the universe was static until Hubble's observations suggested otherwise. Astrophysicists thought they had a good idea about the mass and energy content of the universe until "dark" enrgy showed up. Inglation predicts that the universe is flat, but it has not been properly tested as a theory yet. The next set of WMAP data on the cosmic background, due any month, could help decide the issue. Until then, Luminet's article on cosmic topology is recommended.