An embarrasment of riches for relativity
4 May 2012 by Evoluted New Media
Einstein’s view of the Universe has gained yet more evidence as cosmologists better understand the acceleration of the Universe.
A team from the University of Portsmouth and the Max Planck Institute for Extraterrestrial Physics examined the period between five and six billion years ago, when the Universe was half its present age. Their observations – made with extraordinary accuracy to within 1.7% – tell us more than ever before about the accelerating expansion of the Universe.
“The results are the best measurement of an intergalactic distance ever made which means cosmologists are closer than ever to understanding why the Universe’s expansion is accelerating,” said Dr Rita Tojeiro, from the University of Portsmouth.
“One of the great things about Einstein’s general theory of relativity is that it is testable. Our results support the theory and are consistent with the notion that constant vacuum energy is driving the acceleration of the Universe. These are profound statements that describe the physics of our Universe at the most fundamental level.”
The team examined over 250,000 galaxies within a volume 4 billion light years across using Baryon Acoustic Oscillation (BAO) – a pattern in the way galaxies are distributed across the Universe created shortly after the Big Bang. This pattern survived as the Universe got older, with the size increasing in line with expansion.
The Portsmouth team were instrumental in uncovering the results – they removed interference from our galaxy to permit a clearer picture of the galaxies further away. They then created computer models of alternative universes based on data about our own in which many more experiments could be carried out.
“We used a supercomputer to create ‘fake’ universes that share the same broad characteristics as our own, and this allows us to carry out multiple observations and assess the statistical accuracy of the measurements of the Universe in which we live,” said Dr Marc Manera.
The results will be used to understand what is causing the acceleration and why, and will shed new light on dark energy – the force driving acceleration.
“We know that seven billion years ago dark energy had a much smaller impact on the Universe and one of our aims is to discover what changed – and why,” said Professor Will Percival. “Science often works on first discovering the effect of something, and then investing the cause.”
