What is that mysterious object sending signals towards Earth?

28 Jan 2022

An artist’s impression of what the object might look like. Image: ICRAR

Discovered by Australian university student Tyrone O’Doherty, the ‘spooky’ object may be a type of neutron star that has, until now, only existed in theory.

Scientists and enthusiasts of all things bright and beautiful in the night sky have been captivated by the news of a mysterious object in space releasing massive bursts of energy every 20 minutes.

Suspected by the team that discovered it to be the collapsed core of a star, such as a neutron star or a white dwarf, the object was found to be spinning around in space with an unusually powerful magnetic field and one of the brightest sources of radio waves in the sky.

It was discovered by Tyrone O’Doherty, a student at Curtin University in Perth, Australia, using the Murchison Widefield Array (MWA) telescope situated deep in the outback of Western Australia.

O’Doherty said he was excited that the source “has turned out to be such a peculiar object”. It has now been detailed in a paper published in Nature.

Located in the indigenous territory of the Wajarri Yamatji people of Australia’s mid-west, the MWA observatory was set up in 2009 and is managed by the national science agency of Australia.

“The MWA’s wide field of view and extreme sensitivity are perfect for surveying the entire sky and detecting the unexpected,” O’Doherty said.

Dr Natasha Hurley-Walker, an astrophysicist at the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), led the team that made the discovery. She noted that the mysterious object was “appearing and disappearing over a few hours” during the team’s observations – baffling them all.

“That was completely unexpected. It was kind of spooky for an astronomer because there’s nothing known in the sky that does that,” she said. “And it’s really quite close to us – about 4,000 light years away. It’s in our galactic backyard.”

Why is it unusual?

Erratic behaviour isn’t unusual for objects in space, especially during the dramatic death of a massive star, which can emit huge amounts of energy into the void of space. These objects are known as ‘transients’.

“When studying transients, you’re watching the death of a massive star or the activity of the remnants it leaves behind,” explained Dr Gemma Anderson, another astrophysicist based in the ICRAR-Curtin node.

Anderson said that while ‘slow transients’ such as supernovae may appear over the course of a few days and disappear in a few months, ‘fast transients’ such as pulsars flash on and off within seconds.

However, finding a source that send signals for a minute is highly unusual, according to Anderson, who said the mysterious object was incredibly bright and smaller than the sun. The highly polarised radio waves suggest that the object also has an extremely strong magnetic field.

According to The Guardian, Hurley-Walker dismissed the possibility that a highly technologically advanced civilisation was trying to reach out. “It’s definitely not aliens,” she said, admitting that the team briefly considered the possibility.

Hurley-Walker clarified that because the signal was detectable across a broad spectrum of frequencies, an immense amount of energy would have been required to produce it.

She noted that the team’s observations match a predicted astrophysical object known as an ultra-long period magnetar. This is a type of slowly spinning neutron star that has been predicted to exist theoretically but has not been observed.

“But nobody expected to directly detect one like this because we didn’t expect them to be so bright. Somehow, it’s converting magnetic energy to radio waves much more effectively than anything we’ve seen before,” added Hurley-Walker.

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Vish Gain is a journalist with Silicon Republic