ABSTRACT
Ever since radio astronomy was accidentally invented in 1931, scientists have dreamed of larger and more sensitive telescopes to dig deeper into the mysteries of the universe. It was not long before they realized that multiple radio-telescopes connected together could realize many of the benefits of a single very-large (and impossibly expensive to build!) telescope; many of these so- called ‘connected-element arrays’ have been built since the 1960s, with many still operating today. Still not satisfied, scientists began to explore the possibilities of removing the wire connections which limited these arrays to relatively small geographic areas, allowing the individual telescopes to spread out over very large distances, a step first successfully demonstrated in 1967. Since then, the practice of Very Long Baseline Interferometry (or ‘VLBI’, as it has become to be known) has progressed to include Earth-size telescope arrays doing amazing work, such as making the most detailed images of some of the most distant objects in the universe, determining the positions of distant extragalactic radio objects to extraordinary precision, determining the size of the black hole at the center of our galaxy, directly measuring continental drift, and exquisitely measuring the wiggles and wobbles of the Earth as it moves through space. We will explore the world of VLBI and its many aspects, including a pre-view of exciting instruments planned to be built in Australia and elsewhere.

SPEAKER PROFILE
Alan Whitney has been active in VLBI radio-astronomy development and research since the late 1960's. In 1971, he discovered the first ''super-luminal'' quasar, which appeared to violate the ''nothing faster than the speed-of-light'' law. For many years he has been active in VLBI technique and signal-processing development, leading numerous projects in this area. In the 1990's he led the American team in an international effort to develop a powerful new VLBI processing system, which is now installed in several places in the world. Recently, he has spearheaded the development of magnetic-disk-based VLBI data systems, which are expected to rapidly replace the traditional magnetic-tape-based systems. Alan is the chairman of the global VLBI technology standards committee and also is the Technology Coordinator for the International VLBI Service. Most recently, he has become active in developing and promoting e-VLBI technology and is leading this work at MIT Haystack Observatory. Alan holds the B.S., M.S. and Ph.D. degrees from Massachusetts Institute of Technology and is associate director of the MIT Haystack Observatory.

Lecture sponsored by the School of Mathematics and Physics and the Australian Institute of Physics.