Man in the Moon tunes into Earth’s Radio

Dec 18, 2012

If you ever thought what happens on Earth stays on Earth, think again. Astronomers have now reported that we are sending more signals into space than we know, and we might not be the only ones in the Universe listening in.

CAASTRO PhD student Ben McKinley from the ANU Research School of Astronomy and Astrophysics calculated the strength of the Earth’s radio signals, and found that listening in on us would be feasible, provided an alien civilisation had far superior technologies to our own.

But even if others could eavesdrop, the information would be out of date as our nearest neighbour, Proxima Centauri, is approximately four light years away from Earth.

Ben worked with other CAASTRO members and the international consortium of the Murchison Widefield Array (MWA) project in Western Australia – one of three precursor instruments to Square Kilometre Array. They found that the Moon reflects signals from our TV and radio stations in the FM band (87.5 – 108 MHz).

“The Moon is of course a well-known celestial object to everyone on Earth, especially astronomers, so we were looking at it to see if we could use it as a stable and predictable way to calibrate our telescopes,” said Ben.

“What we actually found was that the moon is reflecting every breaking news story, Top 10 hit, football score, press conference, soap opera and mixed together in a noisy echo of all the Earth’s FM radio signals played simultaneously.”

The MWA telescope is highly sensitive to radio frequencies in the 80-300 MHz range and has been designed to search for the very faint signals from the formation of the first stars in the early Universe. To avoid man-made radio frequency interference from nearby radio and TV stations, the MWA is located in the outback of Western Australia, at CSIRO’s Murchison Radio-astronomy Observatory.

Ben conducts his research under the supervision of CAASTRO Chief Investigator Professor Frank Briggs as part of ‘The Evolving Universe’ theme.

Publication details:
McKinley et al. “Low Frequency Observations of the Moon with the Murchison Widefield Array
The Astronomical Journal 145, 23 (January 2013)

Media Resources:
ANU press release
CAASTRO Video Press Release (2:30 minutes on Youtube)

Contact information:
Mr Ben McKinley
Phone (02) 6125 8025, Mobile 0424 871 986

Dr Wiebke Ebeling (CAASTRO Education & Outreach Coordinator)
Phone (08) 9266 9174, Mobile 0423 933 444

Ms Katharine Pierce (ANU Communications Officer)
Phone (02) 6125 5575, Mobile 0416 249 221