Imagine a world where we couldn't precisely measure the Earth's shape, track tectonic plate movements, or even navigate with GPS. Sounds chaotic, right? This is where Very Long Baseline Interferometry (VLBI) steps in as a silent hero of geodesy, the science of measuring and understanding our planet. A groundbreaking website (https://vlbi.auscope.org.au/) has been launched to demystify the critical role of VLBI in geodesy and its broader impact on the geospatial community. But here's where it gets fascinating: while most people have never heard of it, VLBI is the backbone of technologies we rely on daily, from GPS accuracy to earthquake monitoring.
This resource is a treasure trove for anyone looking to refresh their geodetic knowledge or explain complex concepts like the International Terrestrial Reference Frame (ITRF) (https://itrf.ign.fr/en/homepage) to non-experts. In simple terms, the ITRF is like a global coordinate system that helps us map the Earth with pinpoint precision. The website breaks down how VLBI works, its significance for scientists, engineers, and society at large, and the intricate process of data production and analysis. It also highlights Australia's pivotal role in the global VLBI network, a point that might surprise many.
Australia boasts three VLBI stations—located near Hobart, Katherine, and Yarragadee in Western Australia—that together form the AuScope VLBI Array (https://auscope.phys.utas.edu.au/). These telescopes are workhorses, conducting multiple geodetic observation sessions weekly. In fact, by 2025, Australian telescopes are expected to participate in a staggering 90% of all international geodetic VLBI experiments. And this is the part most people miss: in a global ranking of radio telescopes by observing hours in 2025, Australia's three telescopes dominate the top spots, each logging between 3,000 and 4,000 hours annually. This isn't just a testament to Australia's technical prowess but also to the strategic placement of these telescopes in the Southern Hemisphere.
The data collected by these telescopes is processed by a ‘correlator’ housed on the Gadi supercomputer (https://nci.org.au/our-systems/hpc-systems) in Canberra, part of the National Computational Infrastructure. Up to one petabyte of data is allocated for this purpose—a mind-boggling amount that underscores the scale of this endeavor. But here's where it gets controversial: while VLBI is undeniably crucial, its reliance on massive computational resources raises questions about accessibility and sustainability in less developed regions. Shouldn't this technology be more democratized?
The website also delves into related topics like the International Celestial Reference Frame (ICRF) (https://aa.usno.navy.mil/faq/ICRS_doc), Earth orientation parameters (https://geodesy.science/item/earth-orientation-parameter/), and the International VLBI Service for Geodesy & Astrometry (IVS) (https://ivscc.gsfc.nasa.gov/). At the heart of it all are active galactic nuclei (AGN), distant astronomical objects that serve as reference points for VLBI observations. These AGNs are like cosmic lighthouses, guiding our measurements of the Earth's position and motion in space.
Developed by Dr. David Schunck and Dr. Lucia McCallum from the geodetic VLBI research group at the University of Tasmania (UTAS), this website is part of an AuScope communication project in collaboration with Geoscience Australia and UTAS. It’s a stellar example of how complex science can be made accessible and engaging. But we want to hear from you: Do you think VLBI's impact is underappreciated? And should more countries invest in this technology to ensure global geodetic equity? Let us know in the comments!
