Australasian Science: Australia's authority on science since 1938

Square Kilometre Array Nearing Completion

By David Reneke

Phase 1 of the Square Kilometre Array is nearing completion, and citizen scientists can help with one of the biggest astronomy projects of the next 10 years.

The Square Kilometre Array (SKA) is a multi-billion dollar international project to build the world’s largest radio telescope. Co-located primarily in South Africa and Western Australia, the SKA will be a collection of hundreds of thousands of radio antennas with a combined collecting area equivalent to approximately 1 km2.

The project is one of the largest scientific endeavours in history and will be more than ten times more sensitive and much faster at surveying galaxies than any current radio telescope. The unprecedented flow of data from the telescope will be supported by supercomputing facilities with several times the processing speed of any current supercomputer and one trillion times the computing power that landed men on the Moon.

The SKA will use two different configurations of radio antennas. Australia’s Murchison region will host the low-frequency component, while the mid-frequency infra­structure will be based in South Africa’s Karoo desert. Construction activities for the SKA is expected to commence in late 2020, with preliminary science results a few years after that.

With its incredible sensitivity, the SKA will look back 13 billion years in time to the universe’s Dark Ages. The SKA’s extraordinary sensitivity will allow us to indirectly study gravitational waves from powerful cosmic processes, such as a pair of orbiting black holes. The extreme sensitivity of the SKA is also expected to reveal new planets outside our solar system, some of which may be capable of supporting life.

More than three-quarters of all matter in the universe can’t be observed directly because it doesn’t absorb light. This matter is called dark matter, and its nature remains one of the greatest mysteries in the universe.

The rapid survey speed of the SKA will produce detailed maps of the mass and motions in millions of galaxies, helping us to figure out the nature and abundance of dark matter and elusive dark energy in the universe in an effort to refine our cosmological models.

Volunteers Can Help Unlock the Secrets of the Universe
Scientists are appealing for public help with one of the biggest astronomy projects of the next 10 years. In a new citizen science project launched last month, AstroQuest researchers are looking for volunteers to study images of galaxies and figure out which light is coming from which galaxy.

When you go outside and look up at the night sky, there’s a lot of black with all of the stars dotted around, but when you look with a really powerful telescope for a long time you actually see that there are galaxies and stars everywhere, all over the sky, with most of the stars overlapping each other.

Dr Luke Davies of the University of Western Australia helps lead the Wide Area Vista ExtraGalactic Survey (WAVE), the biggest spectroscopic galaxy evolution survey ever undertaken. Essentially WAVES accurately measures the light coming from millions of galaxies and uses sophisticated computer algorithms to make sense of where the light is coming from in these crowded regions. “But the computer often gets it wrong. It’s simply no match for the human eye and brain,” Davies said

Unfortunately the data base is increasing and there simply aren’t enough people on the team to do the analysis. Citizen science project officer Lisa Evans said AstroQuest asks volunteers to take over from professional astronomers and check the computer’s work.

Knowing the amount of light that comes from a galaxy can tell astronomers how many stars the galaxy currently has, how many are forming and how much dust is in it. “We can actually see how galaxies change as the universe gets older,” Davies said.

AstroQuest is a chance for anyone interested in astronomy to be at the forefront of scientific research and help out a huge million-dollar international project just by being at your computer and drawing over the data. How cool is that!


David Reneke is an astronomy lecturer, writer and broadcaster (www.davidreneke.com).