Stargazing with the SKA

[Music plays and the Maths inside, UTS, AAMT and CSIRO logos and text appears: Investigating the maths inside, Stargazing with SKA]

 

[Image appears of a satellite moving around the globe and then the camera zooms in on Australia on the globe and then in on the desert area in Australia]

 

[Image changes to show a car driving past satellite dishes and then the camera follows the car as it moves down a red dirt road and past a “Radio Quiet Zone” sign]

 

Dr Lisa Harvey-Smith: When I was about 12 years old, my dad took me in the garden and showed me the planet Mars in the night sky.

 

[Image changes to show Dr Lisa Harvey-Smith driving along in the car and then looking out the window at a satellite dish]

 

It was an incredible, sort of exciting moment and I remember being inspired by that.

 

[Image changes to show the car driving past the satellite dishes and then the image changes to show a view of one of the satellite dishes moving around]

 

After that I really got into astronomy even though I hadn’t imagined myself as a scientist. And here I am having a great time enjoying what I do.

 

[Music plays and the image changes to show a night sky with formulas written across it in the background and text in the foreground: #MATHEMATICS]

 

[Images move through of Lisa driving along in the car, her hands on the wheel, her face in the rear vision mirror, and Lisa getting out of the car]

 

When I was very young and studying maths at school, I didn’t really understand sometimes the applications of maths in the real world but now as a professional scientist I can see how absolutely vital it is and it helps us to do all sorts of amazing things.

 

[Music plays and the image shows Lisa walking across a carpark towards a building]

 

[Image changes to show Lisa talking to the camera and text appears: Dr Lisa Harvey-Smith, Astronomer, CSIRO]

 

I’m Lisa Harvey-Smith and I work as an astronomer at the CSIRO in Sydney.

 

[Image changes to show a rear view of Lisa walking towards a satellite dish]

 

I’m the Project Scientist for a new project called ASKAP, the Australian SKA Path Finder.

 

[Camera zooms in on the satellite dish and then the image changes to show a view of the telescopes in the ASKAP array in the daytime and then against a night sky]

 

We’re building a giant radio telescope in Western Australia to study the distant secrets of the universe.

 

[Image changes to show the globe spinning in the night sky and then the camera zooms in on the ASKAP array site]

 

The Square Kilometre Array is a giant global project being built in two countries, in South Africa and also in Australia.

 

[Image changes to show the telescopes at the ASKAP site and then the image changes to show Lisa talking to the camera]

 

This is going to be the most powerful telescope by about 50 times and much more powerful than anything we’ve got right now.

 

[Image changes to show the telescopes at the ASKAP site and the camera pans over the site]

 

It will look at the sky, not in the visible light that we can see with our eyes but in radio waves.

 

[Camera then pans up the telescope from bottom to top]

 

And these are working together, as a team of telescopes to help us to study distant galaxies and stars.

 

[Image changes to show Lisa talking to the camera]

 

Radio telescopes are very different from normal optical telescopes.

 

[Images move through of light bouncing off the satellite dish of a telescope against a night sky, the night sky, and a telescope in the desert]

 

So, instead of just getting the light and bouncing it off a mirror or collecting it in a, with a lens and taking a photograph, we have to do a lot of mathematical things and calculations to actually make a picture with these radio waves.

 

[Image changes to show the satellite dish on the telescope rotating around and then the image changes to show an animation of the parabolic dish and the refraction of the waves]

 

The reason we use a parabolic dish is that the radiation from space is coming in as a plain wave. It’s a straight line and a parabolic dish ensures that all the radiation when it hits the dish and goes into the focus travels the same distance.

 

[Image changes to show the satellite dishes in the ASKAP array moving around and pointing at the night sky]

 

It’s a very good way to turn a straight line, a plain wave into a wave that’s created right at the centre.

 

[Image changes to show the ASKAP array in the desert landscape and then the camera zooms in on some of the telescopes]

 

If the telescopes were regularly spaced, for example in a square or a rectangular distribution, then there’s a lot of redundancy in the array. That is, there are lots of directions and distances that are exactly the same as one another.

 

[Image changes to show Lisa talking to the camera and then the image changes to show a telescope in the foreground of the ASKAP array]

 

So, we want to avoid this redundancy and that’s why the distribution of the telescopes actually looks quite random but in fact there’s a lot of mathematics involved in that calculation of how to distribute the telescopes.

 

[Image changes to show Lisa at her desk and then working on her computer]

 

There’s a huge amount of maths in turning radio waves and information from the sky into pictures.

[Camera zooms in on Lisa’s face as she works and then the image changes to show a rear view of Lisa working in front of three computer screens]

 

The first thing is using, we use complex numbers and the radio waves have an amplitude and a phase.

 

[Image changes to show Lisa’s fingers typing on the keyboard and then the image changes to show a rear view of Lisa working in front of three screens]

 

There’s two properties that we’re interested in and if you want to record the altitude and the phase of the wave at the same time we use something called complex numbers to actually measure this information.

 

[Image changes to show linking lines all around the world globe and the camera zooms out to show that globe spinning in the night sky]

 

But the SKA will have thousands of radio telescopes spread over thousands of kilometres and will be streaming so much data into our super computer, it will be about ten times more than the current total global internet traffic.

 

[Image changes to show a male standing at a door and then the image changes to show a massive cooling system in a room and then text appears over the image: Megabytes]

 

So, we’re talking about computers, about a million times more powerful than our current desktop computers.

 

[Text appears over the image: Gigabytes]

 

So, you’ve heard of megabytes of data and gigabytes.

 

[Image changes to show a massive computer system in a room and then the camera zooms in on the computers and text appears across the image: Terabytes, Petabytes, Exabytes]

 

We’re currently looking at terabytes and petabytes and even exabytes of data from the telescopes.

 

[Images move through of the computer system and then the image changes to show Lisa standing in her office and talking to the camera]

 

So, we’re going to have to have incredibly powerful computers in the future and very clever software to enable us to extract the science from these data.

 

[Text appears across the image: 72 trillion calculations per second!!!!!]

 

The ASKAP super computer, which is sort of the brain of the telescope, performs about 72 trillion calculations per second which is another enormous number.

 

[Camera zooms in on Lisa talking to the camera and then the image changes to show a night sky and a very large digit number counting through extremely fast and stopping on the number: 70,000,000,000,000,000,000,000]

 

Space is absolutely ginormous, and we have to use a lot of big numbers in our work. For example, there are about 70 sextillion stars in our universe. That’s a seven with 22 zeros after it.

 

[Image changes to show telescopes in the ASKAP array against a night sky and the camera pans around the sky]

 

Maths is an amazing tool and it’s often misunderstood.

 

 

[Camera zooms in on a telescope pointing at the Milky Way and then the image changes to show a group of telescopes in the ASKAP array]

 

We know how maths works but sometimes you can apply it to completely new problems that nobody has ever done before and that’s what we’re having to do in these new projects, is to use techniques, use mathematics, to answer new questions and to study new phenomena.

 

[Image shows the telescopes all changing direction in sync and then the camera zooms in on the dishes and then the image changes to show the telescope in the distance against the sky]

 

For example, we can measure radio waves from chemicals in space and we can use calculus to help us to understand where the chemicals came from.

 

[Image shows the dishes all moving in sync and then the image changes to show a hill with trees on it silhouetted against a night sky]

 

We also use trigonometry in the work that we do in astronomy. It’s a really great tool to measure for example the distances to stars and help us to understand the structure of the galaxy, the Milky Way that we live in.

 

[Images move through of Lisa standing in her office talking to the camera, a diagram showing measuring the distance of a star in relation to the sun, and Lisa talking to the camera again]

 

So, imagine you want to measure the distance to a nearby star, what we can do is we can measure the position of the star in the sky and then we wait six months and measure it again.

 

[Image changes to shows a diagram of the earth rotating around the sun and then the image shows measurements linking the earth on either side of the sun to the star]

 

What happens in that six months is that the earth rotates around the sun and we know the distance from the earth to the sun so that gives us twice that distance, gives us the distance along the side of the triangle.

 

[Image changes to show Lisa talking to the camera]

 

We can measure with our telescopes the angle that the star moves in the sky over those six months and using trigonometry that gives us the distance to the star.

 

[Image changes to show a male student sitting in the office and talking to Lisa]

 

Student: So, what do you think is the best thing about maths?

 

[Camera zooms in on their faces]

 

Lisa Harvey-Smith: Well, maths is amazing.

 

[Image changes to show Lisa looking at a screen with data on it and then the image changes to show Lisa’s hands typing on the keyboard]

 

I mean it’s a great tool but it’s also quite a personal challenge isn’t it, when you’re trying to solve an equation. You know there’s a logical way to do it. There’s rules.

 

[Camera zooms out to show a rear view of Lisa working at her computer]

 

When you get to use it in your career and your job, you can use it to solve problems and it can be quite creative as well.

 

[Image changes to show Lisa in her office talking to the camera]

 

Maths is so much more than a load of equations. It’s everything.

 

[Image changes to show three telescopes in the ASKAP array]

 

It’s science, it’s business, it’s finance. It can just take you anywhere. It can take you into so many careers.

 

[Image changes to show the ASKAP array in the distance against a starry sky]

 

So, it’s so important that we understand that maths has a really important place in our world.

 

[Music plays and the Maths Inside logo and text appears: Investigating the maths inside, Maths Inside is a project led by University of Technology Sydney, and funded by the Commonwealth Department of Education and Training under the Australian Maths and Sciences Partnership Program, The aim of Maths Inside is to increase engagement of secondary school students in mathematics, by using rich tasks that show the ways it is used in real world applications, To find out more about this project and other AMSPP resources, please go to http://dimensions.aamt.edu.au, Maths Inside 2016 except where otherwise indicated, the Maths Inside materials may be used, reproduced, communicated and adapted free of charge for non-commercial educational purposes provided all acknowledgements associated with the material are retained, Maths Inside is a UTS project in collaboration with CSIRO and AAMT]