'Dark energy' camera captures first images of the universe
A giant astronomical camera designed to help scientists study ‘dark energy’ has captured its first images of the universe.
The telephone-box-size 570-megapixel Dark Energy Camera, built with the help of UK scientists at a mountaintop observatory in Chile, can capture light from more than 100,000 galaxies up to eight billion light-years away in each shot.
An international team of researchers plans to use the camera to study the layout of galaxies in order to better understand a mysterious phenomenon known as ‘dark energy’, which is thought to explain why the expansion of the universe is speeding up.
Prof Ofer Lahav from University College London (UCL), who heads the UK consortium for the Dark Energy Survey (DES), said in a statement: ‘The achievement of first light through the Dark Energy Camera brings us a step closer to understanding dark energy, one of the biggest mysteries in the whole of physics.
‘The deep observations with the DES camera will tell us why the universe is speeding up and if a major shift is required in our understanding of the universe.’
The camera, whose construction was supported by the UK Science and Technology Facilities Council (STFC), uses an array of 62 charged-coupled devices that are highly sensitive to red light, together with the 13ft light-gathering mirror at the Cerro Tololo Inter-American Observatory, to make detailed images of the night sky.
It will enable the survey team, which is led by the US government’s particle physics centre Fermilab, to study galaxy clusters, supernovae, the large-scale clumping of galaxies, and weak gravitational lensing (the way gravity bends light) — the first time these four phenomena have been examined in one experiment.
Dark energy is a hypothetical form of energy thought to make up around 75 per cent of all the matter and energy in the universe. Because it is impossible to see directly, scientists hope to be able to learn more about it by studying how it affects other phenomena.
Plymouth University’s Prof Will Percival, who co-coordinates the galaxy clustering of DES, said: ‘This will be the largest galaxy survey of its kind, and the galaxy shapes and positions will tell us a great deal about the nature of the physical process that we call dark energy, but do not currently understand.’
Cambridge University’s Prof Richard McMahon, another researcher in the UK team, said: ‘The construction of a three-dimensional map of the galaxies just based on their positions and optical colours is extremely challenging and will require sophisticated computational and statistical techniques.
‘The addition of galaxy near-infrared colours from another UK-led sky-mapping survey — the VISTA Hemisphere Survey — will greatly improve the accuracy of the map.’
The survey is expected to begin in December once the camera is fully tested. Over five years, it will create detailed colour images of one-eighth of the sky — or 5,000 square degrees — to discover and measure 300 million galaxies, 100,000 galaxy clusters, and 4,000 supernovae.
In addition to STFC’s contribution, DES is supported by funding from the US Department of Energy, the National Science Foundation, and funding agencies in Spain, Brazil, Germany and Switzerland, as well as the participating DES institutions.