* Astronomy

A novel telescope that will aid the understanding of the early universe is moving closer to full-scale construction thanks to a $4.9 million award from the National Science Foundation to a U.S. consortium led by MIT.

The Mileura Widefield Array - Low Frequency Demonstrator (LFD), which is being built in Australia by the United States and Australian Partners, will also allow scientists to better predict solar bursts of superheated gas that can play havoc with satellites, communication links and power grids. In support of the solar observations, the Air Force Office of Scientific Research also recently made a $0.3M award to MIT for array equipment.

"The design of the new telescope is tightly focused on frontier experiments in astrophysics and heliospheric science. We plan to harness the enormous computing power of modern digital electronic devices, turning thousands of small, simple, cheap antennas into one of the most potent and unique astronomical instruments in the world" - Colin J. Lonsdale, the project's leader at MIT's Haystack Observatory.

LFD collaborators in the United States are the Haystack Observatory, the MIT Kavli Institute for Astrophysics and Space Research and the Harvard-Smithsonian Centre for Astrophysics. Australian partners include the CSIRO Australia Telescope National Facility and an Australian university consortium led by the University of Melbourne, that includes the Australian National University, Curtin University of Technology and others.
The primary mission of the LFD is to find the first stars, and the primordial galaxies within which they ignited.

How will the telescope accomplish this?
It turns out that hydrogen, which made up most of the ordinary matter in the early universe, efficiently emits and absorbs radio waves. It is these radio waves, stretched by the expansion of the universe, which can be detected, measured and analysed by the new telescope. By spotting the fluctuations in brightness across broad swaths of sky at these wavelengths, we can discover the state of the hydrogen gas when the universe was a tiny fraction of its current age.

The LFD will be an array of 500 antenna "tiles" spread out over an area 1.5 kilometres, or almost a mile, in diameter. Each tile is about 20 feet square and consists of 16 simple and cheap dipole antennas, fixed on the ground and staring straight up.
Big conventional telescopes are characterised by huge concave disks that tip and tilt to focus on specific areas of the sky. Thanks to modern digital electronics, the LFD tiles can also be "steered" in any direction -- but no moving parts are required. Rather, the signals, or data, from each small antenna are brought together and analysed by powerful computers. By combining the signals in different ways, the computers can effectively "point" the telescope in different directions.

"Modern digital signal processing, enabled by advances in technology, are transforming radio astronomy" - Lincoln J. Greenhill of the Harvard-Smithsonian Centre for Astrophysics.

The LFD telescope will operate at the same radio wavelengths where FM radio and TV broadcasts are normally found. So if it were sited near a busy metropolis, signals from the latter would swamp the radio whispers from the deep universe. The planned site at Mileura, in Western Australia, however, is exceptionally "radio quiet" and is also highly accessible.

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