Jacinta Bowler
Jacinta Bowler is a science journalist at Cosmos.
They were published in the Best Australian Science Writing 2023.
Dr Vanessa Moss currently spends her days asleep, and her nights working at one of Australia’s most powerful radio telescopes – The Australian Square Kilometre Array Pathfinder (ASKAP) in Murchison, WA.
The telescope, which when it opened was able to map about three million galaxies in just 300 hours. Comparable surveys of the sky have taken as long as 10 years. ASKAP has been able to track fast radio bursts, find new pulsars, and discover weird new space objects. One of the programs that is part of ASKAP is looking at galaxies from three billion years ago.
But what would an astronomer like Moss do if they had access to an even more powerful telescope?
“ASKAP is powerful in the sense that it’s using new technology – phased array feeds – to open up our view of the sky,” says Moss.
“And you know, it has a lot of impact as a result of that because it can look at the universe in a different way.”
As exciting and powerful as ASKAP is, there’s always ways to go bigger and better.
Optical telescopes – like Hubble and the James Webb Space Telescope – are already in orbit. Could radio telescopes also take to the skies?
“One of the places astronomers have talked about is the far side of the Moon so then you’d always be facing away from Earth,” says Moss.
“There’s discussions about – if you could build a [radio] telescope on the Moon, what would you do there?”
Of course, this is all hypothetical, but it would allow astronomers to get away from radio frequency interference from things like satellites or wi-fi and provide a wider range of radio frequencies for them to explore.
The far side of the Moon sounds exciting, but what about size? Moss explains that Tianyan, the Five-hundred-meter Aperture Spherical Telescope (FAST) in China, is getting up to the maximum size for this type of telescope before physics starts to get messy.
“FAST in China was super ambitious. That’s probably about as physically big as you can get a single dish sitting in a valley,” she told Cosmos.
“You start to get affected by physics.”
Unfortunately, there’s no ‘one (large) size fits all’ for questions in astrophysics. Certain questions need certain telescopes to answer it, and a telescope that’s immensely ‘powerful’ in some respects might be not so good in others.
For example, if you were looking to answer questions on primordial hydrogen in the early universe, you need a radio telescope which can measure large wavelengths at around 100 megahertz. A telescope like ASKAP (with its frequency range from 700 MHz to 1.8 GHz) wouldn’t be helpful for this job. Whereas a telescope currently being built in the same area of WA called the SKA-low, which can receive signals from 50 to 350 MHz, would be perfect.
However, without building any new telescopes there is a way that astronomers around the world can wring a lot more out of their data.
“I think one of the underutilised possibilities right now is that we have so much data coming in from telescopes everywhere – optical, radio, infrared, X ray. And if we’re usually trying to answer specific science questions with them a lot of the other stuff in the data is noise,” says Moss.
“I think that’s a missed opportunity … Some code, or machine learning, or intelligence that can look at all the data, ever and then try to find these outliers.”
Maybe the most powerful hypothetical telescope has been with us all along.
Would You Rather is a new series from the Cosmos news team where two of our science journalists scientifically answer the world’s silliest questions. This week the team asked, ‘would you rather have access to the most powerful telescope or the most powerful microscope? You can listen above.