Earth’s Largest Telescope Soon to Scan Cosmos for Extraterrestrial Signals




The image above shows the supermassive black hole in the core of a distant galaxy known as Cygnus A spews jets of gas into space over distances of more than 200,000 light-years. The jets (orange) were imaged by the new International Low-Frequency Array (LOFAR) Telescope in Europe. The picture shows how the jets slam into the hot gas surrounding the galaxy (blue, imaged by NASA's Chandra x-ray space telescope). 

Last year, scientists in the Netherlands unveiled the largest radiotelescope in the world, saying it was capable of detecting faint signals from almost as far back as the Big Bang  as well as hunting for the first stars and galaxies and potentially signals of extraterrestrial intelligence. 

The LOFAR (LOw Frequency ARray) consists of 20,000 small antennas measuring between 50 centimetres and two metres across spread out across the rest of the Netherlands and also in Germany, Sweden, France and Britain, said Femke Boekhorst of the Netherlands Radioastronomy Institute.  

The array consist of banks of antennas in 48 stations hooked up by fiber optic cables. Signals from these stations will be combined using a supercomputer, transforming the array into "perhaps the most complex and versatile radio telescope ever attempted," said Heino Falcke, chairman of the board for the International LOFAR Telescope.

"The observations that we will be able to make will allow us to learn more about the origin of the universe, back to the moment right after the Big Bang," Boekhorst told AFP.  The data gathered by the telescope will be dealt with by a supercomputer at the university of Groningen and then transmitted to the institute.

Currently 16,000 of LOFAR's antennas and 41 of its stations are operational. The array will be completed by the middle of this year. When completed, LOFAR will have a resolution equivalent to a telescope 620 miles (1,000 kilometers) in diameter. 

Since LOFAR is so large, it can scan large parts of the heavens — its first all-sky survey, which started Jan. 9, can sweep across "the entire northern sky twice in just 45 days," said George Heald of ASTRON.
LOFAR is also very fast, capable of measuring events only five-billionths of a second long.

The array is designed to monitor low-frequency radio waves, a largely unexplored part of radiation from the sky. One critical source of these radio emissions are extremely feeble signals from the cold hydrogen gas that dominated the cosmos during the so-called dark ages of the universe. As stars eventually came into being, they would have left scars on this hydrogen, and by analyzing how the radio signals from this gas changed over time, scientists can therefore learn much about how the first galaxies came to be. 

"This is a pivotal phase in the early evolution of the universe, stretching from 400 million to 800 million years after the Big Bang," said Ger de Bruyn of ASTRON. "We'd like to know when exactly it happened, how it happened, how fast it happened."

LOFAR will also scan for artificial radio emissions as part of the search for extraterrestrial intelligence (SETI). Past SETI missions focused on higher frequency radio waves, but perhaps alien civilizations preferred lower frequencies.

"Low-frequency radio waves are also emitted around intensely powerful cosmic objects such as black holes, and investigating these could help scientists better understand the inner workings of these ferocious systems. For instance, when it comes to pulsars — the highly magnetized and rapidly rotating neutron stars that can form after supernovas — LOFAR can monitor radio emissions from within about 60 miles (100 kilometers) of the pulsar's surface, said Jason Hessels of ASTRON.

LOFAR will open its capabilities to astronomers internationally starting in May. 

The Daily Galaxy via,  AFP and

Image credit: (c) J. McKean and M. Wise, ASTRON


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