China Builds World’s Largest Something

Just how accurate are the reports, chatter and hype surrounding China’s glittering new Five-hundred-meter Aperture Spherical Telescope?

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AsianScientist (Jul. 18, 2016) – My newsfeeds have been abuzz with stories of the completion of China’s Five-hundred-meter Aperture Spherical Telescope (FAST) last week.

Some outlets are describing it as the world’s largest radio telescope, which is just not true—that title goes to the Russian RATAN-600 radio telescope. Some are more correctly describing as it as the world’s largest single-aperture radio telescope. Many are focusing on the extra-terrestrial (ET) signal-seeking capabilities of the telescope in question.

One thing is for sure. China has built something big, and it does indeed resemble a radio telescope.

As a former science communicator for the European Southern Observatory, I am interested in the differences in how stories are reported. I remember during our news team meetings how we would go through the planned stories for the following week, and pick out the elements we wanted to emphasize to see if we could truthfully apply a superlative adjective to the headline. Is this star the biggest? Is it the hottest ever? Furthest? Oldest?

Superlatives make for good, eye-catching headlines. They are even better if true.

Some FAST figures

So what’s the deal with FAST? It is located in a naturally-formed basin in Guizhou Province, Southwestern China, and is designed to scan the skies in the 10 cm-4.3 m wavelength region. Similar to how traditional optical telescopes create images from the visible light portion of the spectrum, FAST will be imaging with photons emitted from radio waves originating from cosmic sources. Hence the term, radio telescope.

FAST is bigger, better and, um… faster than other single aperture radio telescopes, such as the one housed at the Arecibo Observatory in Puerto Rico. It has ten times the sensitivity of Arecibo and also being capable of deforming its dish, allowing for viewing of +/-40° of zenith. In contrast, Arecibo is a static dish, and points to a fixed position in the sky.

Costing some US$180 million, FAST has been designed with a variety of science goals in mind, including hydrogen line (HI) observations of the galactic interstellar medium, searching for approximately 4,000 new galactic pulsars and the first extra-galactic pulsars, seeking out tens of thousands of HI galaxies, and detecting individual massive galaxies. And as a bonus, it can search for alien radio signals from exoplanets.

It should be stated however, that contrary to media hype, it was not built with the purpose of seeking out ET. Organizations and governments just aren’t that interested in spending hundreds of millions of bucks on the extremely slim chance of picking up the alien equivalent of an I Love Lucy broadcast.

But it’s good spin, and it makes a good headline, so I can see why certain outlets have gone with it. The general public is less interested in the finer details of astronomy as much as they are in pretty pictures of nebulae and stories of potential alien contact.

What’s in a name?

So that is why it was built. Let’s have a look at that acronym in a little more detail. Scientists love acronyms almost as much as they love trying to convolute project names until they actually fit the acronym itself. How well did they do on naming FAST?

Well, it’s definitely 500 meters in diameter, although only 300 meters of that are of any use. So the ‘F’ in FAST is perhaps a little optimistic, but we can allow it. It definitely has an Aperture, so the ‘A’ is okay. Now, the ‘S’ stands for spherical, but in geometric terms, the FAST dish is in reality a parabola rather than a segment of a sphere, so ‘P’ is probably more accurate.

So given that the acronym is questionable, and that FAST isn’t actually the world’s largest radio telescope, how would I, in a perfect world, have framed this story as a headline?

China Has FAPT!
World’s Second Largest Radio Telescope Reaches Completion

(And this is why my former boss never allowed me to write headlines.)

But all joking aside, it’s a very cool project and will hopefully produce some valuable science, and some pretty pictures too.

FAPT—correction, FAST, will begin operations in September 2016.

This article is from a monthly column called Final Frontiers. Click here to see the other articles in this series.


Copyright: Asian Scientist Magazine; Photo: National Astronomical Observatories of China.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Phillip Keane has a bachelor degree in aerospace engineering from Coventry University, UK, and an MSc in Space Studies from International Space University in France. He loves all things space and science fiction.

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