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How Australian telescopes are ‘Capturing the Cosmos’

A new planetarium show highlights two new frontiers in Australian astrophysics

Today, astronomers are exploring the universe on a grand scale. But knowing what’s out there is just the first step. It’s putting the pieces together to unlock the mysteries of the universe that is the ultimate goal.

This cosmic jigsaw puzzle has been illustrated in a new planetarium show, Capturing the Cosmos. Narrated by Geoffrey Rush, this is the first show that Australia’s major planetariums, located in Brisbane, Sydney, Wollongong, Melbourne, Bendigo, Launceston, Adelaide and Perth, have joined together for a national release.

The who has been produced through a partnership between Melbourne Planetarium and the ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), a collaboration of seven Australian universities, including the University of Melbourne.

CAASTRO has a “big sky” approach to astronomy. It tackles the big questions in astronomy that can only be answered by observing as much of the southern sky as possible. It’s a wonderful fit for the planetarium, which through its unique projection system (known in the industry as fulldome), completely immerses audiences into the grandness of the night sky and the richness of the data collected by CAASTRO.

With every passing century, telescopes improved and the sights became more detailed and more intriguing.Credit: Melbourne Planetarium

Capturing the Cosmos focuses on two new Australian telescopes.

SKYMAPPER

SkyMapper’s advanced digital camera can capture large sections of the sky and because the telescope captures its images so quickly, it’s also capable of repeating those observations. It observes each patch of sky many times over and can detect changes that occur, as distant objects rapidly brighten or fade away. It turns out the sky is a lot more dynamic than we can ever experience for ourselves.

SkyMapper, an automated telescope in northern New South Wales, is building a vast new catalogue of stars and galaxies that are millions of times fainter than the eye can see. Video: Melbourne Planetarium/Alex Cherney

THE MURCHISON WIDEFIELD ARRAY

The second telescope is quite different. It’s called the Murchison WideField Array, or more commonly the MWA, and it sees things that our eyes can’t. This telescope captures radio waves, ‘light’ that is less energetic than the light we see with our eyes.

These are the telescopes that CAASTRO is using to explore the universe and answer their big questions. An interesting challenge with producing the planetarium show, was how could we make our audiences as excited about unlocking the mysteries of the universe, as the CAASTRO astronomers clearly are?

For each telescope, we decided to focus on one big question. For SkyMapper that was the mystery of dark energy, an unknown force that is pushing space apart. Because astronomers still have so much to learn about dark energy, we began to look for an analogy that could make the idea more grounded.

What we came up with, is to compare dark energy with the wind. A snowflake spiralling around on a windy day, shows you the effect of the wind. And likewise, astronomers have seen the effect that dark energy has on distant galaxies. Now the challenge for astronomers is to find out what dark energy is and how it works.

Meanwhile, a focus for the MWA is to explore the universe’s distant past. It’s an amazing thing about astronomy that when we look up at the night sky, we are looking back in time.

Astronomers can look right back to when the universe was very young and see some of the earliest galaxies to have formed. But there’s a limit. If we look back any further, we hit a time called the Cosmic Dark Ages. The MWA is going to be one of the first telescopes that can peer across the Cosmic Dark Ages and help us understand how the first stars and galaxies lit up the universe.

The first stars and galaxies light up the Universe. Video: Melbourne Planetarium

Rachel Webster from the University of Melbourne, and a member of CAASTRO, helped us to visualise the early universe. She says that back when the Universe began there was almost no structure.

“It was very smooth – just hydrogen gas,” she says.

“Then it got rougher and more complex as stars and galaxies began to form. By the time the universe was one billion years old it was fairly similar to what it was today.”

But the most interesting part is what was happening in that first billion years.

To astronomers like Professor Webster, this is a natural thing to want to know and represents a significant discovery waiting to be made. But how could we share the excitement of that search with the general public?

If we could put together a journal of the Universe’s past, how would we fill all the pages? Picture: Melbourne Planetarium
If we could put together a journal of the Universe’s past, how would we fill all the pages? Picture: Melbourne Planetarium

In Capturing the Cosmos we imagine putting together a journal of the Universe’s life. If we were to create such a record, we would get to a point where the pages of our journal go blank. The Cosmic Dark Ages represents a major gap in our records, just as if there was gap in our own personal life story. It’s a gap that’s worth exploring and will help explain how the universe came to be the way it is today.

Capturing the Cosmos describes the developments that are happening right here in Australia as astronomers explore the universe from our beautiful southern sky. There are known mysteries that astronomers are working to solve, but these telescopes also have the potential to discover things that will lead to even further questions and mysteries. And that’s the way science moves forward.

Great advances in astronomy occur whenever we look at the sky in new and innovative ways.

Dr Tanya Hill is the writer and director of Capturing the Cosmos, which is screening in planetariums around Australia from 22 March 2016. Click here for screenings at Scienceworks Melbourne or check the website of your local planetarium.

Banner Image: The Murchison Widefield Array beneath the radio sky that the MWA records.Melbourne Planetarium / MWA GLEAM Team / Alex Cherney

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