World’s Largest Radio Telescope Spies Its First Pulsars

Still in its trial run, the China’s FAST radio telescope has already identified two new pulsars and perhaps a dozen more

Artist's depiction of a pulsar. SA/JPL-Caltech

China’s massive FAST radio telescope is still officially in its test phase. Though it will take several more years to fully calibrate, as the Xinhua news agency reports, the world’s largest radio telescope is already detecting new pulsars.

Located in Guizhou Province, the telescope has a parabolic dish the size of 30 football fields. The massive device was turned on in September of last year to scour the skies for traces of possible life and undiscovered worlds.

The National Astronomical Observatories of China confirmed that the telescope discovered two pulsars in August while scanning the galactic plane: one called J1859-01 that is 16,000 light years away and a second called J1931-01 about 4,100 light years away. The Parkes radio telescope in Australia has confirmed the finding.

These aren’t the only pulsars the telescope has found. Li Di, chief scientist of the project says that the scope has discovered a dozen pulsar candidates, with six of them confirmed so far. Deputy director of the telescope Peng Bo, tells Xinhua that it will take three to five years for the telescope to become fully functional, but these early discoveries are promising.

“It is truly encouraging to have achieved such results within just one year,” he says.

Pulsars are super-dense celestial objects in a category known as neutron stars, Calla Cofield​ wrote for last year. A pulsar is formed when a massive star runs out of fuel, collapsing in on itself before exploding in a supernova. The dense core left behind is a pulsar.

As the pulsar spins inside a magnetic field—which is up to 100 million to 1 quadrillion times as strong as Earth’s magnetic field—it causes the pulsar to produce two steady beams of radiation streaming in opposite directions, like a lighthouse, writes Cofield. But because pulsars spin, from Earth it looks like they are flickering on and off. From that flickering, astronomers can calculate how fast the objects are spinning. While most  pulsars spin roughly once per second, some spin hundreds of times per second and are known as millisecond pulsars.

Since the first pulsar was discovered by chance in 1967, over 2,000 of the objects have been catalogued. So far, however, all of those lie within our Milky Way Galaxy. Once FAST is fully operational, reports Xinhua, researchers hope to locate the first pulsars outside this galaxy.

It's an important step for astronomy, Emily Petroff from the Netherlands Institute for Radio Astronomy tells Ryan F. Mandelbaum at Gizmodo. “Pulsars are useful for studying the ionized material in our galaxy, their radio pulses travel through the interstellar medium and allow us to measure its properties,” she says. “So having a pulsar in another galaxy would be a super powerful tool from probing the interstellar (and intergalactic) medium in between us and another galaxy. That’s never been done before.”

The telescope will also search for gravitational waves, organic molecules in space and any possible signals from extraterrestrial civilizations. The FAST facility surpasses the Arecibo Radio Telescope in Puerto Rico, which was damaged recently during hurricane Maria, as the world’s largest. While Arecibo can scan around 20 degrees of the sky, FAST will be able to scan 40 degrees and can do so five to ten times faster.

The mega-machine was built at a cost of $180 million and led to the displacement of 8,000 people living near the natural depression where it is located (such positioning reduces radio interference). In fact, the machine is so impressive it has created another problem: interference from the millions of tourists who are flocking to take a look at one of the wonders of the modern world.

While FAST is likely to dominate radio astronomy for the next couple decades, plans are already underway for an even bigger, though much different, radio telescope, reports Xinghua: the Square Kilometer Array project​. Once completed, it will have over 200 dishes and over 1 million antennae split between locations in Africa and Australia.

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