Telescope able to explore the mysteries of universe
DURHAM UNI ACADEMICS HELPED TO BUILD INSTRUMENT
A TELESCOPE that can ‘look into the past’ and show scientists how the universe is expanding has been created with the help of Durham academics.
The Dark Energy Spectroscopic Instrument (DESI), designed and built by an international collaboration including Durham University, this week aimed its 5,000 fibre-optic ‘eyes’ at the night sky for the first time.
The telescope instrument is designed to provide very precise measurements of the Universe’s expansion rate. This expansion rate, thought to have slowed in the early Universe due to gravity, has recently been found to be speeding up – but experts don’t yet know why.
Dark energy is one ingredient thought to be contributing to this, and DESI will seek to measure its effect.
The installation of the instrument on the four-metre Mayall Telescope at the Kitt Peak National Observatory in Arizona, in the United States, is nearly complete and DESI has captured its first images of galaxies up to 11 billion light years away.
When formal observations begin in 2020, the instrument will be used to ‘look back in time’ to create the most detailed 3D map of the Universe ever created, examining light sent out up to 11 billion years ago, which has only just reached earth.
The cutting-edge instrument was built with the collaboration of nearly 500 researchers at 75 institutions in 13 countries. The UK’s Science and Technology Facilities Council handed £2.4m in funding to Durham University and University College London to help fund the instrument’s development.
Professor Ofer Lahav from UCL, the chair of the DESI UK consortium of seven universities, said:
“The ability of DESI to capture the spectra of 5,000 different galaxies simultaneously is about 10 times more than previously achieved. By looking back in time by up to about 11 billion years, DESI will expose secrets of the universe’s infancy and early development. This new information will help us better understand the physical processes driving the accelerating expansion of the universe, one of the key unsolved questions in physics. It will also teach us about the nature of dark matter, including finding the mass of the illusive neutrinos.”
The fibre-optic system, led by Dr Luke Tyas’ team at Durham University,
carries the light to the spectrograph, where it splits that light into narrow bands of colour to precisely map their distance from Earth and gauge how much the universe expanded as this light travelled to Earth. In ideal conditions DESI can cycle through a new set of 5,000 galaxies every 20 minutes.
DESI team member Professor Carlos Frenk from Durham University said: “The DESI project epitomizes the best of modern science. It is designed to answer a fascinating question about the fundamental fabric of our universe: what is causing the cosmic expansion to speed up? It will collect 10 times more data on galaxies, quasars and stars in the Milky Way than humans have collected to date, stretching back to the early phases of our universe. Bringing together scientists from 13 countries, DESI shows how people from across the globe can come together to tackle keyscientific questions.”
By repeatedly mapping the distance to 35 million galaxies and 2.4 million quasars across one-third of the area of the sky over its five-year run, DESI will teach us more about dark energy. Quasars, among the brightest objects in the universe, allow DESI to look deeply into the Universe’s past.
DESI is led by the Lawrence Berkeley National Laboratory (LBNL) in the US, supported by funding from the Department of Energy.
“After a decade in planning and R&D, installation and assembly, we are delighted that DESI can soon begin its quest to unravel the mystery of dark energy,” said DESI Director Michael Levi of LBNL.
“Most of the universe’s matter and energy are dark and unknown, and next-generation experiments like DESI are our best bet for unravelling these mysteries,” he added. “I am thrilled to see this new experiment come to life.”