Friday 17 March 2023 1:36pm

John Pickering - image
Professor John Pickering was one of 31 citizen scientists from around the world who monitored the asteroid in the lead-up and aftermath of the collision.

A University of Otago, Christchurch academic and citizen scientist has contributed to a research paper about NASA's first planetary defence test by capturing data about an asteroid in his backyard.

In November 2021, NASA launched its Double Asteroid Redirection Test (DART) mission, sending a spacecraft into space to hit Dimorphos, a moon of the non-threatening asteroid Didymos. The aim was to test if scientists can deflect an asteroid away from the Earth if it was on track to damage it.

The spacecraft hit Dimorphos in September 2022 and shortened its orbit by 32 minutes.

Ahorangi Rangahau John Pickering, of the Department of Medicine, was one of 31 citizen scientists from around the world who monitored the asteroid in the lead-up and aftermath of the collision.

“Only four citizen scientists actually saw the event of the spacecraft hitting the moon of the asteroid but for that to be meaningful you have to have the data of the asteroid beforehand and afterwards,” Professor Pickering says, adding that some of his data looked at the asteroid before the impact.

The citizen scientists, all using the same Unistellar eVscope telescope which takes photos every few seconds, measured the asteroid's brightness and trajectory.

Didymos - Unistellar eVscope image
Professor John Pickering captured this image of the asteroid Didymos in September last year using his Unistellar eVscope telescope. SUPPLIED

Those measurements were then analysed by professionals at the SETI (Search for Extraterrestrial Intelligence) Institute.

SETI Institute research scientist Dr Ariel Graykowski collated the data and led a research paper, published in the world's leading multidisciplinary science journal Nature earlier this month.

Findings included how long it took Dimorphos to return to its normal brightness (24 days), and how much mass was ejected from it (0.3-0.5% or 13,000-22,000 tonnes), and the surprise observation of the red colour of the ejecta which may yet yield information about the composition of the surface of Dimorphos.

While Professor Pickering has published many papers over the years, it was a new experience for some of the citizen scientists.

When they found out the paper had been accepted, he messaged the group and told them about a tradition he had with his family, which was to celebrate with a cheesecake.

“The fun thing with this was that people got on board, even the lead author mentioned it in an article,” he says.

“Then the head of the NASA team that sent the spacecraft sent a congratulatory note about the paper and said, 'I hope you enjoy the cheesecake'.

“So that was a bit of fun. I'm starting a new trend with astronomers,” he says, laughing.

While he may work in the Department of Medicine now, astronomy has been a lifelong hobby.

He had a telescope as a teenager, studied physics at the University of Canterbury - which has elements of astronomy in it - and enjoys showing his neighbours and community groups the stars in the sky.

“I'm a professor and published in top medical journals but there's something special about going way back to my original physics days.”

He fondly describes detecting in 2021 his “first planet around another star from this tiny little telescope” in his backyard.

“There's something thrilling about that.

“It's also really satisfying to be supporting post docs and PhD students, just in a different way.”

Didymos asteroid - image
An image of the asteroid Didymos. SUPPLIED

While neither Didymos nor Dimorphos are a threat to Earth, the results of the DART mission are significant.

“At the moment that is our best hope if something we detect is coming and could hit us.

“Prior to this all we had was the theory that we could deflect it. Now we know it is possible, so it gives that hope.”

Professor Pickering plans to continue observing the night sky and hopes others will do the same.

“You don't have to have a background in physics to enjoy the night sky.”

Back to top