Researchers from the University of Manchester in the UK have employed an advanced network of supercomputers to look at mysterious components of the universe known as dark energy and dark matter.
The team used GridPP, the British part of a European network that was used in the discovery of the Higgs boson, to run image processing and a machine learning algorithm. The goal was to quantify the cosmic shear, also known as weak gravitational lensing, an apparent distortion in the shape of galaxies due to foreground dark matter bending their light.
GridPP was fed images from the Dark Energy Survey, which is mapping hundreds of millions of galaxies and looking for patterns in the cosmic structure. This study is a precursor to more intensive work that will be possible to do with the Large Synoptic Survey Telescope (LSST) currently under construction in Chile.
“Our overall aim is to tackle the mystery of the dark universe – and this pilot project has been hugely significant,” Professor Sarah Bridle said in a statement. “When the LSST is fully operating researchers will face a galactic data deluge – and our work will prepare us for the analytical challenge ahead.”
This computational approach, nicknamed IM3SHAPE, will have to deal with the 200 Petabyte (200 billion Megabytes) of data from the LSST when it becomes operational in 2023. It can produce shear analysis on vast images with an unprecedented speed.
The cosmic shear is nothing like the beautiful arcs seen in strong gravitational lenses. It is a small distortion and it would go unnoticed on a single galaxy. But if many background galaxies appear to all be distorted in the same way, it tell us there’s something we cannot see in front of them.
That something is what we call dark matter, a mysterious substance that only interacts with gravity and not with the other forces. Dark matter explains why galaxies have certain shapes and, although other theories have been proposed, it remains the most robust explanation.
But when cosmic shear is estimated in 3D, it can also be used to find out the properties of the other mysterious component of the universe: dark energy. The universe is expanding at an accelerated rate and the cause of it seems to be dark energy. We don’t know much more than that, but these studies will hopefully bring forth a better understanding of the dark universe.
