[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.08,0:00:03.84,Default,,0000,0000,0000,,Space, the final frontier.
Dialogue: 0,0:00:05.88,0:00:09.34,Default,,0000,0000,0000,,I first heard these words\Nwhen I was just six years old,
Dialogue: 0,0:00:09.36,0:00:11.62,Default,,0000,0000,0000,,and I was completely inspired.
Dialogue: 0,0:00:11.64,0:00:14.02,Default,,0000,0000,0000,,I wanted to explore strange new worlds.
Dialogue: 0,0:00:14.04,0:00:15.54,Default,,0000,0000,0000,,I wanted to seek out new life.
Dialogue: 0,0:00:15.56,0:00:18.76,Default,,0000,0000,0000,,I wanted to see everything\Nthat the universe had to offer.
Dialogue: 0,0:00:19.84,0:00:23.54,Default,,0000,0000,0000,,And those dreams, those words,\Nthey took me on a journey,
Dialogue: 0,0:00:23.56,0:00:25.02,Default,,0000,0000,0000,,a journey of discovery,
Dialogue: 0,0:00:25.04,0:00:27.22,Default,,0000,0000,0000,,through school, through university,
Dialogue: 0,0:00:27.24,0:00:30.68,Default,,0000,0000,0000,,to do a PhD and finally\Nto become a professional astronomer.
Dialogue: 0,0:00:31.92,0:00:34.94,Default,,0000,0000,0000,,Now, I learned two amazing things,
Dialogue: 0,0:00:34.96,0:00:36.50,Default,,0000,0000,0000,,one slightly unfortunate,
Dialogue: 0,0:00:36.52,0:00:38.58,Default,,0000,0000,0000,,when I was doing my PhD.
Dialogue: 0,0:00:38.60,0:00:41.02,Default,,0000,0000,0000,,I learned that the reality was
Dialogue: 0,0:00:41.04,0:00:44.20,Default,,0000,0000,0000,,I wouldn't be piloting\Na starship anytime soon.
Dialogue: 0,0:00:45.44,0:00:50.06,Default,,0000,0000,0000,,But I also learned that the universe\Nis strange, wonderful and vast,
Dialogue: 0,0:00:50.08,0:00:52.88,Default,,0000,0000,0000,,actually too vast\Nto be explored by spaceship.
Dialogue: 0,0:00:53.72,0:00:57.08,Default,,0000,0000,0000,,And so I turned my attention\Nto astronomy, to using telescopes.
Dialogue: 0,0:00:57.84,0:01:00.62,Default,,0000,0000,0000,,Now, I show you before you\Nan image of the night sky.
Dialogue: 0,0:01:00.64,0:01:02.56,Default,,0000,0000,0000,,You might see it anywhere in the world.
Dialogue: 0,0:01:03.04,0:01:07.00,Default,,0000,0000,0000,,And all of these stars are part\Nof our local galaxy, the Milky Way.
Dialogue: 0,0:01:07.56,0:01:10.26,Default,,0000,0000,0000,,Now, if you were to go\Nto a darker part of the sky,
Dialogue: 0,0:01:10.28,0:01:12.82,Default,,0000,0000,0000,,a nice dark site, perhaps in the desert,
Dialogue: 0,0:01:12.84,0:01:15.26,Default,,0000,0000,0000,,you might see the center\Nof our Milky Way galaxy
Dialogue: 0,0:01:15.28,0:01:18.24,Default,,0000,0000,0000,,spread out before you,\Nhundreds of billions of stars.
Dialogue: 0,0:01:18.84,0:01:20.42,Default,,0000,0000,0000,,And it's a very beautiful image.
Dialogue: 0,0:01:20.44,0:01:21.78,Default,,0000,0000,0000,,It's colorful.
Dialogue: 0,0:01:21.80,0:01:25.42,Default,,0000,0000,0000,,And again, this is just\Na local corner of our universe.
Dialogue: 0,0:01:25.44,0:01:28.74,Default,,0000,0000,0000,,You can see there's\Na sort of strange dark dust across it.
Dialogue: 0,0:01:28.76,0:01:30.74,Default,,0000,0000,0000,,Now, that is local dust
Dialogue: 0,0:01:30.76,0:01:33.42,Default,,0000,0000,0000,,that's obscuring the light of the stars.
Dialogue: 0,0:01:33.44,0:01:35.02,Default,,0000,0000,0000,,But we can do a pretty good job.
Dialogue: 0,0:01:35.04,0:01:38.50,Default,,0000,0000,0000,,Just with our own eyes, we can explore\Nour little corner of the universe.
Dialogue: 0,0:01:38.52,0:01:39.86,Default,,0000,0000,0000,,It's possible to do better.
Dialogue: 0,0:01:39.88,0:01:43.64,Default,,0000,0000,0000,,You can use wonderful telescopes\Nlike the Hubble Space Telescope.
Dialogue: 0,0:01:44.20,0:01:46.38,Default,,0000,0000,0000,,Now, astronomers\Nhave put together this image.
Dialogue: 0,0:01:46.40,0:01:48.30,Default,,0000,0000,0000,,It's called the Hubble Deep Field,
Dialogue: 0,0:01:48.32,0:01:52.66,Default,,0000,0000,0000,,and they've spent hundreds of hours\Nobserving just a tiny patch of the sky
Dialogue: 0,0:01:52.68,0:01:55.08,Default,,0000,0000,0000,,no larger than your thumbnail\Nheld at arm's length.
Dialogue: 0,0:01:55.52,0:01:56.78,Default,,0000,0000,0000,,And in this image
Dialogue: 0,0:01:56.80,0:01:58.46,Default,,0000,0000,0000,,you can see thousands of galaxies,
Dialogue: 0,0:01:58.48,0:02:01.94,Default,,0000,0000,0000,,and we know that there must be\Nhundreds of millions, billions of galaxies
Dialogue: 0,0:02:01.96,0:02:03.34,Default,,0000,0000,0000,,in the entire universe,
Dialogue: 0,0:02:03.36,0:02:06.02,Default,,0000,0000,0000,,some like our own and some very different.
Dialogue: 0,0:02:06.04,0:02:08.70,Default,,0000,0000,0000,,So you think, OK, well,\NI can continue this journey.
Dialogue: 0,0:02:08.72,0:02:11.42,Default,,0000,0000,0000,,This is easy. I can just\Nuse a very powerful telescope
Dialogue: 0,0:02:11.44,0:02:13.24,Default,,0000,0000,0000,,and just look at the sky, no problem.
Dialogue: 0,0:02:13.96,0:02:17.98,Default,,0000,0000,0000,,It's actually really missing out\Nif we just do that.
Dialogue: 0,0:02:18.00,0:02:20.74,Default,,0000,0000,0000,,Now, that's because\Neverything I've talked about so far
Dialogue: 0,0:02:20.76,0:02:24.66,Default,,0000,0000,0000,,is just using the visible spectrum,\Njust the thing that your eyes can see,
Dialogue: 0,0:02:24.68,0:02:26.10,Default,,0000,0000,0000,,and that's a tiny slice,
Dialogue: 0,0:02:26.12,0:02:29.48,Default,,0000,0000,0000,,a tiny, tiny slice\Nof what the universe has to offer us.
Dialogue: 0,0:02:30.16,0:02:34.90,Default,,0000,0000,0000,,Now, there's also two very important\Nproblems with using visible light.
Dialogue: 0,0:02:34.92,0:02:37.66,Default,,0000,0000,0000,,Not only are we missing out\Non all the other processes
Dialogue: 0,0:02:37.68,0:02:40.86,Default,,0000,0000,0000,,that are emitting other kinds of light,
Dialogue: 0,0:02:40.88,0:02:42.30,Default,,0000,0000,0000,,but there's two issues.
Dialogue: 0,0:02:42.32,0:02:45.70,Default,,0000,0000,0000,,Now, the first is that dust\Nthat I mentioned earlier.
Dialogue: 0,0:02:45.72,0:02:48.66,Default,,0000,0000,0000,,The dust stops the visible light\Nfrom getting to us.
Dialogue: 0,0:02:48.68,0:02:53.38,Default,,0000,0000,0000,,So as we look deeper\Ninto the universe, we see less light.
Dialogue: 0,0:02:53.40,0:02:54.96,Default,,0000,0000,0000,,The dust stops it getting to us.
Dialogue: 0,0:02:55.52,0:02:58.94,Default,,0000,0000,0000,,But there's a really strange problem\Nwith using visible light
Dialogue: 0,0:02:58.96,0:03:00.92,Default,,0000,0000,0000,,in order to try and explore the universe.
Dialogue: 0,0:03:01.64,0:03:03.90,Default,,0000,0000,0000,,Now take a break for a minute.
Dialogue: 0,0:03:03.92,0:03:06.60,Default,,0000,0000,0000,,Say you're standing on a corner,\Na busy street corner.
Dialogue: 0,0:03:07.08,0:03:08.58,Default,,0000,0000,0000,,There's cars going by.
Dialogue: 0,0:03:08.60,0:03:10.00,Default,,0000,0000,0000,,An ambulance approaches.
Dialogue: 0,0:03:10.84,0:03:12.22,Default,,0000,0000,0000,,It has a high-pitched siren.
Dialogue: 0,0:03:12.24,0:03:15.98,Default,,0000,0000,0000,,(Imitates a siren passing by)
Dialogue: 0,0:03:16.00,0:03:18.34,Default,,0000,0000,0000,,The siren appeared to change in pitch
Dialogue: 0,0:03:18.36,0:03:20.44,Default,,0000,0000,0000,,as it moved towards and away from you.
Dialogue: 0,0:03:20.96,0:03:24.84,Default,,0000,0000,0000,,The ambulance driver did not change\Nthe siren just to mess with you.
Dialogue: 0,0:03:26.04,0:03:28.62,Default,,0000,0000,0000,,That was a product of your perception.
Dialogue: 0,0:03:28.64,0:03:31.38,Default,,0000,0000,0000,,The sound waves,\Nas the ambulance approached,
Dialogue: 0,0:03:31.40,0:03:32.62,Default,,0000,0000,0000,,were compressed,
Dialogue: 0,0:03:32.64,0:03:34.58,Default,,0000,0000,0000,,and they changed higher in pitch.
Dialogue: 0,0:03:34.60,0:03:37.38,Default,,0000,0000,0000,,As the ambulance receded,\Nthe sound waves were stretched,
Dialogue: 0,0:03:37.40,0:03:39.46,Default,,0000,0000,0000,,and they sounded lower in pitch.
Dialogue: 0,0:03:39.48,0:03:41.48,Default,,0000,0000,0000,,The same thing happens with light.
Dialogue: 0,0:03:42.04,0:03:44.42,Default,,0000,0000,0000,,Objects moving towards us,
Dialogue: 0,0:03:44.44,0:03:47.62,Default,,0000,0000,0000,,their light waves are compressed\Nand they appear bluer.
Dialogue: 0,0:03:47.64,0:03:49.86,Default,,0000,0000,0000,,Objects moving away from us,
Dialogue: 0,0:03:49.88,0:03:52.54,Default,,0000,0000,0000,,their light waves are stretched,\Nand they appear redder.
Dialogue: 0,0:03:52.56,0:03:55.44,Default,,0000,0000,0000,,So we call these effects\Nblueshift and redshift.
Dialogue: 0,0:03:56.44,0:03:59.38,Default,,0000,0000,0000,,Now, our universe is expanding,
Dialogue: 0,0:03:59.40,0:04:03.58,Default,,0000,0000,0000,,so everything is moving away\Nfrom everything else,
Dialogue: 0,0:04:03.60,0:04:06.28,Default,,0000,0000,0000,,and that means\Neverything appears to be red.
Dialogue: 0,0:04:07.04,0:04:10.78,Default,,0000,0000,0000,,And oddly enough, as you look\Nmore deeply into the universe,
Dialogue: 0,0:04:10.80,0:04:15.10,Default,,0000,0000,0000,,more distant objects\Nare moving away further and faster,
Dialogue: 0,0:04:15.12,0:04:16.84,Default,,0000,0000,0000,,so they appear more red.
Dialogue: 0,0:04:17.56,0:04:20.50,Default,,0000,0000,0000,,So if I come back to the Hubble Deep Field
Dialogue: 0,0:04:20.52,0:04:23.22,Default,,0000,0000,0000,,and we were to continue\Nto peer deeply into the universe
Dialogue: 0,0:04:23.24,0:04:24.78,Default,,0000,0000,0000,,just using the Hubble,
Dialogue: 0,0:04:24.80,0:04:27.50,Default,,0000,0000,0000,,as we get to a certain distance away,
Dialogue: 0,0:04:27.52,0:04:29.12,Default,,0000,0000,0000,,everything becomes red,
Dialogue: 0,0:04:29.92,0:04:31.90,Default,,0000,0000,0000,,and that presents something of a problem.
Dialogue: 0,0:04:31.92,0:04:33.98,Default,,0000,0000,0000,,Eventually, we get so far away
Dialogue: 0,0:04:34.00,0:04:36.98,Default,,0000,0000,0000,,everything is shifted into the infrared
Dialogue: 0,0:04:37.00,0:04:39.00,Default,,0000,0000,0000,,and we can't see anything at all.
Dialogue: 0,0:04:39.68,0:04:41.38,Default,,0000,0000,0000,,So there must be a way around this.
Dialogue: 0,0:04:41.40,0:04:43.22,Default,,0000,0000,0000,,Otherwise, I'm limited in my journey.
Dialogue: 0,0:04:43.24,0:04:45.14,Default,,0000,0000,0000,,I wanted to explore the whole universe,
Dialogue: 0,0:04:45.16,0:04:49.08,Default,,0000,0000,0000,,not just whatever I can see,\Nyou know, before the redshift kicks in.
Dialogue: 0,0:04:50.16,0:04:51.42,Default,,0000,0000,0000,,There is a technique.
Dialogue: 0,0:04:51.44,0:04:52.82,Default,,0000,0000,0000,,It's called radio astronomy.
Dialogue: 0,0:04:52.84,0:04:55.18,Default,,0000,0000,0000,,Astronomers have been\Nusing this for decades.
Dialogue: 0,0:04:55.20,0:04:56.50,Default,,0000,0000,0000,,It's a fantastic technique.
Dialogue: 0,0:04:56.52,0:05:00.01,Default,,0000,0000,0000,,I show you the Parkes Radio Telescope,\Naffectionately known as "The Dish."
Dialogue: 0,0:05:00.04,0:05:01.82,Default,,0000,0000,0000,,You may have seen the movie.
Dialogue: 0,0:05:01.84,0:05:03.42,Default,,0000,0000,0000,,And radio is really brilliant.
Dialogue: 0,0:05:03.44,0:05:05.98,Default,,0000,0000,0000,,It allows us to peer much more deeply.
Dialogue: 0,0:05:06.00,0:05:08.70,Default,,0000,0000,0000,,It doesn't get stopped by dust,
Dialogue: 0,0:05:08.72,0:05:10.98,Default,,0000,0000,0000,,so you can see everything in the universe,
Dialogue: 0,0:05:11.00,0:05:12.86,Default,,0000,0000,0000,,and redshift is less of a problem
Dialogue: 0,0:05:12.88,0:05:16.08,Default,,0000,0000,0000,,because we can build receivers\Nthat receive across a large band.
Dialogue: 0,0:05:16.60,0:05:20.54,Default,,0000,0000,0000,,So what does Parkes see when we turn it\Nto the center of the Milky Way?
Dialogue: 0,0:05:20.56,0:05:22.52,Default,,0000,0000,0000,,We should see something fantastic, right?
Dialogue: 0,0:05:23.16,0:05:26.06,Default,,0000,0000,0000,,Well, we do see something interesting.
Dialogue: 0,0:05:26.08,0:05:27.74,Default,,0000,0000,0000,,All that dust has gone.
Dialogue: 0,0:05:27.76,0:05:31.20,Default,,0000,0000,0000,,As I mentioned, radio goes\Nstraight through dust, so not a problem.
Dialogue: 0,0:05:31.84,0:05:33.74,Default,,0000,0000,0000,,But the view is very different.
Dialogue: 0,0:05:33.76,0:05:37.58,Default,,0000,0000,0000,,We can see that the center\Nof the Milky Way is aglow,
Dialogue: 0,0:05:37.60,0:05:39.28,Default,,0000,0000,0000,,and this isn't starlight.
Dialogue: 0,0:05:39.96,0:05:43.10,Default,,0000,0000,0000,,This is a light called\Nsynchrotron radiation,
Dialogue: 0,0:05:43.12,0:05:47.72,Default,,0000,0000,0000,,and it's formed from electrons\Nspiraling around cosmic magnetic fields.
Dialogue: 0,0:05:48.28,0:05:51.38,Default,,0000,0000,0000,,So the plane is aglow with this light.
Dialogue: 0,0:05:51.40,0:05:54.70,Default,,0000,0000,0000,,And we can also see\Nstrange tufts coming off of it,
Dialogue: 0,0:05:54.72,0:05:57.22,Default,,0000,0000,0000,,and objects which don't appear to line up
Dialogue: 0,0:05:57.24,0:05:59.56,Default,,0000,0000,0000,,with anything that we can see\Nwith our own eyes.
Dialogue: 0,0:06:00.52,0:06:02.66,Default,,0000,0000,0000,,But it's hard to really\Ninterpret this image,
Dialogue: 0,0:06:02.68,0:06:05.46,Default,,0000,0000,0000,,because as you can see,\Nit's very low resolution.
Dialogue: 0,0:06:05.48,0:06:07.66,Default,,0000,0000,0000,,Radio waves have a wavelength that's long,
Dialogue: 0,0:06:07.68,0:06:09.98,Default,,0000,0000,0000,,and that makes their resolution poorer.
Dialogue: 0,0:06:10.00,0:06:12.06,Default,,0000,0000,0000,,This image is also black and white,
Dialogue: 0,0:06:12.08,0:06:15.84,Default,,0000,0000,0000,,so we don't really know\Nwhat is the color of everything in here.
Dialogue: 0,0:06:16.64,0:06:18.02,Default,,0000,0000,0000,,Well, fast-forward to today.
Dialogue: 0,0:06:18.04,0:06:19.50,Default,,0000,0000,0000,,We can build telescopes
Dialogue: 0,0:06:19.52,0:06:22.14,Default,,0000,0000,0000,,which can get over these problems.
Dialogue: 0,0:06:22.16,0:06:25.50,Default,,0000,0000,0000,,Now, I'm showing you here an image\Nof the Murchison Radio Observatory,
Dialogue: 0,0:06:25.52,0:06:28.30,Default,,0000,0000,0000,,a fantastic place\Nto build radio telescopes.
Dialogue: 0,0:06:28.32,0:06:30.62,Default,,0000,0000,0000,,It's flat, it's dry,
Dialogue: 0,0:06:30.64,0:06:33.62,Default,,0000,0000,0000,,and most importantly, it's radio quiet:
Dialogue: 0,0:06:33.64,0:06:36.74,Default,,0000,0000,0000,,no mobile phones, no Wi-Fi, nothing,
Dialogue: 0,0:06:36.76,0:06:39.26,Default,,0000,0000,0000,,just very, very radio quiet,
Dialogue: 0,0:06:39.28,0:06:42.00,Default,,0000,0000,0000,,so a perfect place\Nto build a radio telescope.
Dialogue: 0,0:06:42.88,0:06:45.74,Default,,0000,0000,0000,,Now, the telescope that I've been\Nworking on for a few years
Dialogue: 0,0:06:45.76,0:06:47.70,Default,,0000,0000,0000,,is called the Murchison Widefield Array,
Dialogue: 0,0:06:47.72,0:06:50.74,Default,,0000,0000,0000,,and I'm going to show you\Na little time lapse of it being built.
Dialogue: 0,0:06:50.76,0:06:54.02,Default,,0000,0000,0000,,This is a group of undergraduate\Nand postgraduate students
Dialogue: 0,0:06:54.04,0:06:55.30,Default,,0000,0000,0000,,located in Perth.
Dialogue: 0,0:06:55.32,0:06:57.06,Default,,0000,0000,0000,,We call them the Student Army,
Dialogue: 0,0:06:57.08,0:06:59.90,Default,,0000,0000,0000,,and they volunteered their time\Nto build a radio telescope.
Dialogue: 0,0:06:59.92,0:07:01.56,Default,,0000,0000,0000,,There's no course credit for this.
Dialogue: 0,0:07:02.32,0:07:05.22,Default,,0000,0000,0000,,And they're putting together\Nthese radio dipoles.
Dialogue: 0,0:07:05.24,0:07:10.20,Default,,0000,0000,0000,,They just receive at low frequencies,\Na bit like your FM radio or your TV.
Dialogue: 0,0:07:11.00,0:07:14.10,Default,,0000,0000,0000,,And here we are deploying them\Nacross the desert.
Dialogue: 0,0:07:14.12,0:07:16.54,Default,,0000,0000,0000,,The final telescope\Ncovers 10 square kilometers
Dialogue: 0,0:07:16.56,0:07:18.70,Default,,0000,0000,0000,,of the Western Australian desert.
Dialogue: 0,0:07:18.72,0:07:21.70,Default,,0000,0000,0000,,And the interesting thing is,\Nthere's no moving parts.
Dialogue: 0,0:07:21.72,0:07:23.98,Default,,0000,0000,0000,,We just deploy these little antennas
Dialogue: 0,0:07:24.00,0:07:25.86,Default,,0000,0000,0000,,essentially on chicken mesh.
Dialogue: 0,0:07:25.88,0:07:27.30,Default,,0000,0000,0000,,It's fairly cheap.
Dialogue: 0,0:07:27.32,0:07:29.30,Default,,0000,0000,0000,,Cables take the signals
Dialogue: 0,0:07:29.32,0:07:31.38,Default,,0000,0000,0000,,from the antennas
Dialogue: 0,0:07:31.40,0:07:33.94,Default,,0000,0000,0000,,and bring them\Nto central processing units.
Dialogue: 0,0:07:33.96,0:07:35.74,Default,,0000,0000,0000,,And it's the size of this telescope,
Dialogue: 0,0:07:35.76,0:07:38.42,Default,,0000,0000,0000,,the fact that we've built it\Nover the entire desert
Dialogue: 0,0:07:38.44,0:07:41.24,Default,,0000,0000,0000,,that gives us a better\Nresolution than Parkes.
Dialogue: 0,0:07:41.88,0:07:45.42,Default,,0000,0000,0000,,Now, eventually all those cables\Nbring them to a unit
Dialogue: 0,0:07:45.44,0:07:48.98,Default,,0000,0000,0000,,which sends it off\Nto a supercomputer here in Perth,
Dialogue: 0,0:07:49.00,0:07:50.29,Default,,0000,0000,0000,,and that's where I come in.
Dialogue: 0,0:07:51.32,0:07:52.54,Default,,0000,0000,0000,,(Sighs)
Dialogue: 0,0:07:52.56,0:07:53.78,Default,,0000,0000,0000,,Radio data.
Dialogue: 0,0:07:53.80,0:07:55.62,Default,,0000,0000,0000,,I have spent the last five years
Dialogue: 0,0:07:55.64,0:07:58.50,Default,,0000,0000,0000,,working with very difficult,\Nvery interesting data
Dialogue: 0,0:07:58.52,0:08:00.50,Default,,0000,0000,0000,,that no one had really looked at before.
Dialogue: 0,0:08:00.52,0:08:02.66,Default,,0000,0000,0000,,I've spent a long time calibrating it,
Dialogue: 0,0:08:02.68,0:08:06.58,Default,,0000,0000,0000,,running millions of CPU hours\Non supercomputers
Dialogue: 0,0:08:06.60,0:08:08.80,Default,,0000,0000,0000,,and really trying to understand that data.
Dialogue: 0,0:08:09.36,0:08:11.30,Default,,0000,0000,0000,,And with this telescope,
Dialogue: 0,0:08:11.32,0:08:12.58,Default,,0000,0000,0000,,with this data,
Dialogue: 0,0:08:12.60,0:08:16.54,Default,,0000,0000,0000,,we've performed a survey\Nof the entire southern sky,
Dialogue: 0,0:08:16.56,0:08:21.66,Default,,0000,0000,0000,,the GaLactic and Extragalactic\NAll-sky MWA Survey,
Dialogue: 0,0:08:21.68,0:08:23.56,Default,,0000,0000,0000,,or GLEAM, as I call it.
Dialogue: 0,0:08:24.44,0:08:25.90,Default,,0000,0000,0000,,And I'm very excited.
Dialogue: 0,0:08:25.92,0:08:29.30,Default,,0000,0000,0000,,This survey is just about to be published,\Nbut it hasn't been shown yet,
Dialogue: 0,0:08:29.32,0:08:31.26,Default,,0000,0000,0000,,so you are literally the first people
Dialogue: 0,0:08:31.28,0:08:34.08,Default,,0000,0000,0000,,to see this southern survey\Nof the entire sky.
Dialogue: 0,0:08:34.80,0:08:38.12,Default,,0000,0000,0000,,So I'm delighted to share with you\Nsome images from this survey.
Dialogue: 0,0:08:38.88,0:08:40.78,Default,,0000,0000,0000,,Now, imagine you went to the Murchison,
Dialogue: 0,0:08:40.80,0:08:42.90,Default,,0000,0000,0000,,you camped out underneath the stars
Dialogue: 0,0:08:42.92,0:08:44.54,Default,,0000,0000,0000,,and you looked towards the south.
Dialogue: 0,0:08:44.56,0:08:46.23,Default,,0000,0000,0000,,You saw the south's celestial pole,
Dialogue: 0,0:08:46.25,0:08:47.46,Default,,0000,0000,0000,,the galaxy rising.
Dialogue: 0,0:08:47.48,0:08:50.10,Default,,0000,0000,0000,,If I fade in the radio light,
Dialogue: 0,0:08:50.12,0:08:52.78,Default,,0000,0000,0000,,this is what we observe with our survey.
Dialogue: 0,0:08:52.80,0:08:55.86,Default,,0000,0000,0000,,You can see that the galactic plane\Nis no longer dark with dust.
Dialogue: 0,0:08:55.88,0:08:58.30,Default,,0000,0000,0000,,It's alight with synchrotron radiation,
Dialogue: 0,0:08:58.32,0:09:00.82,Default,,0000,0000,0000,,and thousands of dots are in the sky.
Dialogue: 0,0:09:00.84,0:09:04.14,Default,,0000,0000,0000,,Our large Magellanic Cloud,\Nour nearest galactic neighbor,
Dialogue: 0,0:09:04.16,0:09:07.38,Default,,0000,0000,0000,,is orange instead\Nof its more familiar blue-white.
Dialogue: 0,0:09:07.40,0:09:10.78,Default,,0000,0000,0000,,So there's a lot going on in this.\NLet's take a closer look.
Dialogue: 0,0:09:10.80,0:09:13.22,Default,,0000,0000,0000,,If we look back\Ntowards the galactic center,
Dialogue: 0,0:09:13.24,0:09:16.46,Default,,0000,0000,0000,,where we originally saw the Parkes image\Nthat I showed you earlier,
Dialogue: 0,0:09:16.48,0:09:18.86,Default,,0000,0000,0000,,low resolution, black and white,
Dialogue: 0,0:09:18.88,0:09:20.96,Default,,0000,0000,0000,,and we fade to the GLEAM view,
Dialogue: 0,0:09:22.20,0:09:26.06,Default,,0000,0000,0000,,you can see the resolution\Nhas gone up by a factor of a hundred.
Dialogue: 0,0:09:26.08,0:09:28.94,Default,,0000,0000,0000,,We now have a color view of the sky,
Dialogue: 0,0:09:28.96,0:09:30.30,Default,,0000,0000,0000,,a technicolor view.
Dialogue: 0,0:09:30.32,0:09:33.30,Default,,0000,0000,0000,,Now, it's not a false color view.
Dialogue: 0,0:09:33.32,0:09:35.72,Default,,0000,0000,0000,,These are real radio colors.
Dialogue: 0,0:09:36.60,0:09:39.42,Default,,0000,0000,0000,,What I've done is I've colored\Nthe lowest frequencies red
Dialogue: 0,0:09:39.44,0:09:41.06,Default,,0000,0000,0000,,and the highest frequencies blue,
Dialogue: 0,0:09:41.08,0:09:42.66,Default,,0000,0000,0000,,and the middle ones green.
Dialogue: 0,0:09:42.68,0:09:44.90,Default,,0000,0000,0000,,And that gives us this rainbow view.
Dialogue: 0,0:09:44.92,0:09:47.18,Default,,0000,0000,0000,,And this isn't just false color.
Dialogue: 0,0:09:47.20,0:09:50.14,Default,,0000,0000,0000,,The colors in this image\Ntell us about the physical processes
Dialogue: 0,0:09:50.16,0:09:51.40,Default,,0000,0000,0000,,going on in the universe.
Dialogue: 0,0:09:51.97,0:09:54.74,Default,,0000,0000,0000,,So for instance, if you look\Nalong the plane of the galaxy,
Dialogue: 0,0:09:54.76,0:09:56.22,Default,,0000,0000,0000,,it's alight with synchrotron,
Dialogue: 0,0:09:56.24,0:09:58.62,Default,,0000,0000,0000,,which is mostly reddish orange,
Dialogue: 0,0:09:58.64,0:10:01.76,Default,,0000,0000,0000,,but if we look very closely,\Nwe see little blue dots.
Dialogue: 0,0:10:02.32,0:10:03.90,Default,,0000,0000,0000,,Now, if we zoom in,
Dialogue: 0,0:10:03.92,0:10:06.46,Default,,0000,0000,0000,,these blue dots are ionized plasma
Dialogue: 0,0:10:06.48,0:10:08.12,Default,,0000,0000,0000,,around very bright stars,
Dialogue: 0,0:10:08.68,0:10:11.46,Default,,0000,0000,0000,,and what happens\Nis that they block the red light,
Dialogue: 0,0:10:11.48,0:10:13.12,Default,,0000,0000,0000,,so they appear blue.
Dialogue: 0,0:10:13.88,0:10:16.82,Default,,0000,0000,0000,,And these can tell us\Nabout these star-forming regions
Dialogue: 0,0:10:16.84,0:10:18.10,Default,,0000,0000,0000,,in our galaxy.
Dialogue: 0,0:10:18.12,0:10:19.74,Default,,0000,0000,0000,,And we just see them immediately.
Dialogue: 0,0:10:19.76,0:10:22.82,Default,,0000,0000,0000,,We look at the galaxy,\Nand the color tells us that they're there.
Dialogue: 0,0:10:22.84,0:10:24.42,Default,,0000,0000,0000,,You can see little soap bubbles,
Dialogue: 0,0:10:24.44,0:10:27.86,Default,,0000,0000,0000,,little circular images\Naround the galactic plane,
Dialogue: 0,0:10:27.88,0:10:29.88,Default,,0000,0000,0000,,and these are supernova remnants.
Dialogue: 0,0:10:30.60,0:10:32.30,Default,,0000,0000,0000,,When a star explodes,
Dialogue: 0,0:10:32.32,0:10:34.78,Default,,0000,0000,0000,,its outer shell is cast off
Dialogue: 0,0:10:34.80,0:10:38.10,Default,,0000,0000,0000,,and it travels outward into space\Ngathering up material,
Dialogue: 0,0:10:38.12,0:10:40.08,Default,,0000,0000,0000,,and it produces a little shell.
Dialogue: 0,0:10:40.80,0:10:44.18,Default,,0000,0000,0000,,It's been a long-standing\Nmystery to astronomers
Dialogue: 0,0:10:44.20,0:10:46.28,Default,,0000,0000,0000,,where all the supernova remnants are.
Dialogue: 0,0:10:46.96,0:10:51.30,Default,,0000,0000,0000,,We know that there must be a lot\Nof high-energy electrons in the plane
Dialogue: 0,0:10:51.32,0:10:53.98,Default,,0000,0000,0000,,to produce the synchrotron\Nradiation that we see,
Dialogue: 0,0:10:54.00,0:10:56.58,Default,,0000,0000,0000,,and we think they're produced\Nby supernova remnants,
Dialogue: 0,0:10:56.60,0:10:58.38,Default,,0000,0000,0000,,but there don't seem to be enough.
Dialogue: 0,0:10:58.40,0:11:02.30,Default,,0000,0000,0000,,Fortunately, GLEAM is really, really\Ngood at detecting supernova remnants,
Dialogue: 0,0:11:02.32,0:11:04.80,Default,,0000,0000,0000,,so we're hoping to have\Na new paper out on that soon.
Dialogue: 0,0:11:05.80,0:11:07.06,Default,,0000,0000,0000,,Now, that's fine.
Dialogue: 0,0:11:07.08,0:11:09.42,Default,,0000,0000,0000,,We've explored our little local universe,
Dialogue: 0,0:11:09.44,0:11:11.82,Default,,0000,0000,0000,,but I wanted to go deeper,\NI wanted to go further.
Dialogue: 0,0:11:11.84,0:11:13.92,Default,,0000,0000,0000,,I wanted to go beyond the Milky Way.
Dialogue: 0,0:11:14.52,0:11:18.30,Default,,0000,0000,0000,,Well, as it happens, we can see a very\Ninteresting object in the top right,
Dialogue: 0,0:11:18.32,0:11:20.54,Default,,0000,0000,0000,,and this is a local radio galaxy,
Dialogue: 0,0:11:20.56,0:11:21.80,Default,,0000,0000,0000,,Centaurus A.
Dialogue: 0,0:11:22.24,0:11:23.50,Default,,0000,0000,0000,,If we zoom in on this,
Dialogue: 0,0:11:23.52,0:11:26.92,Default,,0000,0000,0000,,we can see that there are\Ntwo huge plumes going out into space.
Dialogue: 0,0:11:27.60,0:11:30.50,Default,,0000,0000,0000,,And if you look right in the center\Nbetween those two plumes,
Dialogue: 0,0:11:30.52,0:11:32.90,Default,,0000,0000,0000,,you'll see a galaxy just like our own.
Dialogue: 0,0:11:32.92,0:11:35.38,Default,,0000,0000,0000,,It's a spiral. It has a dust lane.
Dialogue: 0,0:11:35.40,0:11:37.02,Default,,0000,0000,0000,,It's a normal galaxy.
Dialogue: 0,0:11:37.04,0:11:40.66,Default,,0000,0000,0000,,But these jets\Nare only visible in the radio.
Dialogue: 0,0:11:40.68,0:11:43.86,Default,,0000,0000,0000,,If we looked in the visible,\Nwe wouldn't even know they were there,
Dialogue: 0,0:11:43.88,0:11:46.92,Default,,0000,0000,0000,,and they're thousands of times larger\Nthan the host galaxy.
Dialogue: 0,0:11:47.48,0:11:49.88,Default,,0000,0000,0000,,What's going on?\NWhat's producing these jets?
Dialogue: 0,0:11:51.16,0:11:54.70,Default,,0000,0000,0000,,At the center of every galaxy\Nthat we know about
Dialogue: 0,0:11:54.72,0:11:56.98,Default,,0000,0000,0000,,is a supermassive black hole.
Dialogue: 0,0:11:57.00,0:12:00.42,Default,,0000,0000,0000,,Now, black holes are invisible.\NThat's why they're called that.
Dialogue: 0,0:12:00.44,0:12:03.46,Default,,0000,0000,0000,,All you can see is the deflection\Nof the light around them,
Dialogue: 0,0:12:03.48,0:12:07.78,Default,,0000,0000,0000,,and occasionally, when a star\Nor a cloud of gas comes into their orbit,
Dialogue: 0,0:12:07.80,0:12:10.54,Default,,0000,0000,0000,,it is ripped apart by tidal forces,
Dialogue: 0,0:12:10.56,0:12:13.04,Default,,0000,0000,0000,,forming what we call an accretion disk.
Dialogue: 0,0:12:13.64,0:12:16.86,Default,,0000,0000,0000,,The accretion disk\Nglows brightly in the x-rays,
Dialogue: 0,0:12:16.88,0:12:21.30,Default,,0000,0000,0000,,and huge magnetic fields\Ncan launch the material into space
Dialogue: 0,0:12:21.32,0:12:23.04,Default,,0000,0000,0000,,at nearly the speed of light.
Dialogue: 0,0:12:23.52,0:12:26.68,Default,,0000,0000,0000,,So these jets are visible in the radio
Dialogue: 0,0:12:27.24,0:12:29.40,Default,,0000,0000,0000,,and this is what we pick up in our survey.
Dialogue: 0,0:12:30.04,0:12:34.06,Default,,0000,0000,0000,,Well, very well, so we've seen\None radio galaxy. That's nice.
Dialogue: 0,0:12:34.08,0:12:36.26,Default,,0000,0000,0000,,But if you just look\Nat the top of that image,
Dialogue: 0,0:12:36.28,0:12:38.02,Default,,0000,0000,0000,,you'll see another radio galaxy.
Dialogue: 0,0:12:38.04,0:12:41.28,Default,,0000,0000,0000,,It's a little bit smaller,\Nand that's just because it's further away.
Dialogue: 0,0:12:41.80,0:12:44.46,Default,,0000,0000,0000,,OK. Two radio galaxies.
Dialogue: 0,0:12:44.48,0:12:46.06,Default,,0000,0000,0000,,We can see this. This is fine.
Dialogue: 0,0:12:46.08,0:12:47.82,Default,,0000,0000,0000,,Well, what about all the other dots?
Dialogue: 0,0:12:47.84,0:12:49.40,Default,,0000,0000,0000,,Presumably those are just stars.
Dialogue: 0,0:12:49.88,0:12:51.10,Default,,0000,0000,0000,,They're not.
Dialogue: 0,0:12:51.12,0:12:52.72,Default,,0000,0000,0000,,They're all radio galaxies.
Dialogue: 0,0:12:53.32,0:12:56.22,Default,,0000,0000,0000,,Every single one of the dots in this image
Dialogue: 0,0:12:56.24,0:12:57.98,Default,,0000,0000,0000,,is a distant galaxy,
Dialogue: 0,0:12:58.00,0:13:00.86,Default,,0000,0000,0000,,millions to billions of light-years away
Dialogue: 0,0:13:00.88,0:13:03.50,Default,,0000,0000,0000,,with a supermassive\Nblack hole at its center
Dialogue: 0,0:13:03.52,0:13:07.10,Default,,0000,0000,0000,,pushing material into space\Nat nearly the speed of light.
Dialogue: 0,0:13:07.12,0:13:08.88,Default,,0000,0000,0000,,It is mind-blowing.
Dialogue: 0,0:13:09.68,0:13:13.42,Default,,0000,0000,0000,,And this survey is even larger\Nthan what I've shown here.
Dialogue: 0,0:13:13.44,0:13:15.98,Default,,0000,0000,0000,,If we zoom out to\Nthe full extent of the survey,
Dialogue: 0,0:13:16.00,0:13:20.10,Default,,0000,0000,0000,,you can see I found 300,000\Nof these radio galaxies.
Dialogue: 0,0:13:20.12,0:13:23.02,Default,,0000,0000,0000,,So it's truly an epic journey.
Dialogue: 0,0:13:23.04,0:13:25.70,Default,,0000,0000,0000,,We've discovered all of these galaxies
Dialogue: 0,0:13:25.72,0:13:29.28,Default,,0000,0000,0000,,right back to the very first\Nsupermassive black holes.
Dialogue: 0,0:13:29.96,0:13:32.74,Default,,0000,0000,0000,,I'm very proud of this,\Nand it will be published next week.
Dialogue: 0,0:13:33.28,0:13:36.10,Default,,0000,0000,0000,,Now, that's not all.
Dialogue: 0,0:13:36.12,0:13:40.46,Default,,0000,0000,0000,,I've explored the furthest reaches\Nof the galaxy with this survey,
Dialogue: 0,0:13:40.48,0:13:43.44,Default,,0000,0000,0000,,but there's something\Neven more in this image.
Dialogue: 0,0:13:44.32,0:13:47.62,Default,,0000,0000,0000,,Now, I'll take you right back\Nto the dawn of time.
Dialogue: 0,0:13:47.64,0:13:51.30,Default,,0000,0000,0000,,When the universe formed,\Nit was a big bang,
Dialogue: 0,0:13:51.32,0:13:55.38,Default,,0000,0000,0000,,which left the universe\Nas a sea of hydrogen,
Dialogue: 0,0:13:55.40,0:13:56.90,Default,,0000,0000,0000,,neutral hydrogen.
Dialogue: 0,0:13:56.92,0:13:59.70,Default,,0000,0000,0000,,And when the very first stars\Nand galaxies switched on,
Dialogue: 0,0:13:59.72,0:14:01.82,Default,,0000,0000,0000,,they ionized that hydrogen.
Dialogue: 0,0:14:01.84,0:14:05.28,Default,,0000,0000,0000,,So the universe went\Nfrom neutral to ionized.
Dialogue: 0,0:14:06.16,0:14:09.34,Default,,0000,0000,0000,,That imprinted a signal all around us.
Dialogue: 0,0:14:09.36,0:14:11.10,Default,,0000,0000,0000,,Everywhere, it pervades us,
Dialogue: 0,0:14:11.12,0:14:12.54,Default,,0000,0000,0000,,like the Force.
Dialogue: 0,0:14:12.56,0:14:16.28,Default,,0000,0000,0000,,Now, because that happened so long ago,
Dialogue: 0,0:14:17.00,0:14:18.80,Default,,0000,0000,0000,,the signal was redshifted,
Dialogue: 0,0:14:19.56,0:14:22.86,Default,,0000,0000,0000,,so now that signal\Nis at very low frequencies.
Dialogue: 0,0:14:22.88,0:14:25.34,Default,,0000,0000,0000,,It's at the same frequency as my survey,
Dialogue: 0,0:14:25.36,0:14:26.74,Default,,0000,0000,0000,,but it's so faint.
Dialogue: 0,0:14:26.76,0:14:30.64,Default,,0000,0000,0000,,It's a billionth the size\Nof any of the objects in my survey.
Dialogue: 0,0:14:31.32,0:14:36.22,Default,,0000,0000,0000,,So our telescope may not be quite\Nsensitive enough to pick up this signal.
Dialogue: 0,0:14:36.24,0:14:38.74,Default,,0000,0000,0000,,However, there's a new radio telescope.
Dialogue: 0,0:14:38.76,0:14:40.42,Default,,0000,0000,0000,,So I can't have a starship,
Dialogue: 0,0:14:40.44,0:14:41.70,Default,,0000,0000,0000,,but I can hopefully have
Dialogue: 0,0:14:41.72,0:14:44.58,Default,,0000,0000,0000,,one of the biggest\Nradio telescopes in the world.
Dialogue: 0,0:14:44.60,0:14:48.22,Default,,0000,0000,0000,,We're building the Square Kilometre Array,\Na new radio telescope,
Dialogue: 0,0:14:48.24,0:14:50.98,Default,,0000,0000,0000,,and it's going to be a thousand\Ntimes bigger than the MWA,
Dialogue: 0,0:14:51.00,0:14:54.22,Default,,0000,0000,0000,,a thousand times more sensitive,\Nand have an even better resolution.
Dialogue: 0,0:14:54.24,0:14:56.46,Default,,0000,0000,0000,,So we should find\Ntens of millions of galaxies.
Dialogue: 0,0:14:56.48,0:14:58.82,Default,,0000,0000,0000,,And perhaps, deep in that signal,
Dialogue: 0,0:14:58.84,0:15:03.02,Default,,0000,0000,0000,,I will get to look upon the very first\Nstars and galaxies switching on,
Dialogue: 0,0:15:03.04,0:15:05.40,Default,,0000,0000,0000,,the beginning of time itself.
Dialogue: 0,0:15:05.92,0:15:07.14,Default,,0000,0000,0000,,Thank you.
Dialogue: 0,0:15:07.16,0:15:09.92,Default,,0000,0000,0000,,(Applause)