Monday, 23 May 2016

Tuning into the music of the cosmos

Written by 
Dr Natasha Hurley-Walker Dr Natasha Hurley-Walker James Campbell

Through a series of profile stories, ScienceNetwork WA takes a look at the people behind the science in Western Australia and what inspires them.

IMAGINE that when you gazed up at the night sky you saw not just stars but hundreds of thousands of galaxies. And imagine these galaxies each had supermassive black holes at their centres visible to the human eye.

Sound like the stuff of Star Trek? Not anymore.

Curtin University astronomer Natasha Hurley-Walker is using a series of telescopes in the Murchison desert to capture FM radio waves.

She then interprets this data to ‘tune into the music of the cosmos’ and, in the process, reveals a world otherwise not viewable to the human eye—a world of exploded stars, black holes and distant galaxies.

Dr Hurley-Walker will reveal the mesmerising images that she’s captured at a Pint of Science talk at The Boston in Northbridge in Perth on May 25.

It’s heady stuff for this astronomer who first became enchanted by night skies as a Scottish kid who grew up in Houston, Texas.

“When I was a kid the biggest trip of the year was going to the Johnson Space Centre in Houston,” she says.

“I just loved it! And as a kid I watched a lot of Star Trek.”

Dr Hurley-Walker’s current project is based at the remote Murchison Radio Observatory—one of the best areas in the country to avoid radio wave frequencies that would interfere with her work. 

Here a series of 4096 radio-wave telescopes are spaced across a 3km x 3km stretch of country in 128 groups.

These telescopes pick up radio waves from the universe, capturing many gigabytes of data every second.

Previously, such raw data was too voluminous to examine. But new software processing can now interpret the data to provide a survey of the sky that is viewable to the human eye.

“The pictures show lots of little dots that look like stars but they’re not stars—every single one is a galaxy and there are hundreds of thousands of them,” Dr Hurley-Walker says.

"But what’s really amazing is that in the middle of every galaxy is a supermassive black hole, which draws in surrounding stars and gas in a huge accretion disk.

“The vast magnetic fields of the disk can sometimes produce massive jets of plasma which stretch into space, thousands of times larger than the host galaxy.

Both the accretion disk and the jets are visible at radio wavelengths, so seeing them in our survey means we're seeing these black holes in action at the centres of hundreds of thousands of galaxies."

Notes:

To buy tickets for the Pint of Science talks and to listen to Dr Hurley-Walker and others in Northbridge next week visit the website.

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