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Scientists hope gravitational wave discovery could open new area of physics -

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MARK COLVIN: Douglas Adams once wrote of a theory that if anyone discovers what the universe is for and why it's here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.

Physicists today inched slightly closer towards testing that theory, by proving Albert Einstein's century-old postulation that gravitational waves exist.

The observation of the waves opens a whole new window and way to look out at the universe we live in.

Scientists say it could trigger a whole new era of physics to learn about.

Will Ockenden reports.

WILL OCKENDEN: There are a lot of tired physicists walking the corridors of academia today.

GERAINT LEWIS: The few things that wake me up at night are international rugby and big science announcements.

WILL OCKENDEN: The announcement overnight was that gravitational waves, first proposed by Einstein 100 years ago, have been proven true and observed for the first time.

Geraint Lewis is a Professor of astrophysics at the University of Sydney, and says the announcement was worth getting up for.

GERAINT LEWIS: I was sort of expecting a blip in the telescope and they said look we've got something.

But it was more than that. They actually have structure that they've seen and this structure is the thing that - is the telltale sign that they've seen black holes merging.

WILL OCKENDEN: The LIGO sensor is a precise piece of equipment that was the first to pick up the existence of gravitational waves.

They were created when two black holes collided more than a billion years ago, sending a ripple across the fabric of space-time.

Geraint Lewis says their discovery will open new ways of looking at and measuring the universe.

GERAINT LEWIS: Firstly of course there will be more gravitational wave detectors built on the planet and in fact there's a big one in Europe already more or less complete - it's going to be fully online in the next few years.

But India, China, Japan, Australia maybe, will all host these gravitational wave telescopes, they'll all be slightly different et cetera.

And we'll start to observe the sky in the same way that optical and radio telescopes observe the sky, so we'll have this new window on the universe.

It's going to reveal a very different universe to the one we see through a normal telescope.

It basically reveals the violent events in the universe - you only create gravitational waves when massive things move in very quickly, crash together, that's how you set these vibrations in space-time.

We'll start to things that will confirm what we understand - that various stars when they go boom will produce gravitational waves - but we will undoubtedly get signals that we can't yet explain. And so we're going to probably have a lot of head-scratching and new theoretical ideas to explain the various things that we'll see.

WILL OCKENDEN: He says the discovery could even help edge physics closer to working out the elusive theory of everything.

GERAINT LEWIS: We will learn more about gravity, which is of course the dominant force in the universe, but it's also the weakest of the forces.

We've been at a bit of a stumbling block for almost a hundred years in that we can't get Einstein's notions of gravity, which work in the large-scale universe, to play nicely with quantum mechanics, which is the physics that describes the very small universe, the thing that makes your iPhone work is quantum mechanics.

And there's been this dream of unifying these two together into a single grand, unified theory and the problem is that still they are separate ideas, they're very different ideas.

Maybe these observations of gravitational waves will tell us something about gravity that will point us in a new direction and these ideas about gravity which will start to bring quantum mechanics and gravity closer together.

WILL OCKENDEN: Tara Murphy is an Associate Professor at the University of Sydney.

She says that it's a rare thing to say that a discovery will open a new window on the universe, but today is one of those days.


She works with radio telescopes like the Murchison Widefield Array and soon the Square Kilometre Array, which will hopefully be used in the future to pinpoint in the sky where gravitational waves are coming from.

TARA MURPHY: LIGO is extremely sensitive at detecting the gravitational waves, but it's really poor at knowing where they are.

So when they detect an event, they know that it's in some large region across the sky, but they don't know exactly where.

What they really want to do is identify it with the host - either the black hole system or the galaxy, whatever that it came from.

What we can do, if the event had radio waves or optical light coming from it as well, we scan the sky over that error region as quickly as possible after the event and look for something that's changed.

WILL OCKENDEN: She says there's a lot of work to do.

TARA MURPHY: We have a whole range of astronomical events that may cause gravitational waves that we just don't know about yet, and so there's that possibility of finding them.

But there's also another really important thing which is the possibility of finding primordial gravitational waves, so right back from the very beginning of the universe.

MARK COLVIN: Associate Professor Tara Murphy of the University of Sydney ending Will Ockenden's report.