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Episode 3: Professor Melanie Johnston-Hollitt

Melanie Johnston-Hollitt is an Australian astrophysicist, professor at Curtin University (Australia) and Director of The Murchison Widefield Array (MWA), a low-frequency radio telescope, located at the Murchison Radio-astronomy Observatory (MRO) in Western Australia.
She is an expert in radio astronomy and has designed, constructed and governed multiple international radio telescopes such as the Lothar long-range telescope array and the Murchison widefield array. Her background spans theoretical physics, pure mathematics and computational science. She has earned multiple international awards for her efforts in creating efficient data pipelines for the massive stream of data coming from large antenna arrays scanning the skies. Professor Johnston-Hollitt has been chairing various international cooperative efforts, the latest being the Square Kilometer Array, which has one core site scheduled to be installed in the Northern Cape Province, South Africa.

Link to video AstroHunters Episode 3

Topic of interview

Radio Astronomy, The Murchison Widefield Array (MWA), big data collection, signals from outer space, and science as a career choice.


  • What is radio astronomy, what is the MWA - overview of the instrumentation
  • What the MWA is used for – exploration, signals
  • “Astronomy is always looking back at the past. Anything we see is how it was, not how it is today.”
  • Application of their scientific exploration in other fields of science : WiFi, medical imaging
  • Signals from outer space - Extraterrestrial?
    Radio astronomy is used if signals or objects are detected that can’t be identified or tied to celestial objects. In 2017 the MWA was also used to show that claims a strangely shaped object, called Oumuamoua, was holding an extraterrestrial message were unfounded.
  • As humans we are limited in thinking about what type of signals we can have.”
    Question: Can you come up with different ways that extra-terrestrials may try to send a signal, send us a message ?
  • Should you choose science or astronomy career path, and could you, if you are blind or visually impaired?
    “Follow your heart and curiosity.”

Terminology and further reading

  • Radio astronomy = astronomy using the radio part of the electromagnetic spectrum
  • MWA = The Murchison Widefield Array. The MWA is a low-frequency radio telescope, located at the Murchison Radio-astronomy Observatory (MRO) in Western Australia. The MWA is performing large surveys of the entire Southern Hemisphere sky and acquiring deep observations on targeted regions. It enables astronomers to pursue four key science objectives. The primary endeavor is the hunt for intergalactic hydrogen gas that surrounded early galaxies during the cosmological epoch of reionization. The MWA will also provide new insights into our Milky Way galaxy and its magnetic field, pulsing and exploding stellar objects, and the science of space weather that connects our Sun to the environment here on Earth.
  • Array = (noun, here:) a large group of things that has been positioned in a particular way
  • Radio galaxies
  • Interferometer (activity in this link is very visual!)
  • Oumamua
  • Gravitational signals 
  • Warp space time
Photo of Professor Melanie Johnston-Hollitt and Yuma Decaux with recording mics on table in small room
Professor Melanie Johnston-Hollitt and Yuma Decaux