[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:15.57,0:00:18.33,Default,,0000,0000,0000,,Space, the final frontier.
Dialogue: 0,0:00:20.37,0:00:23.83,Default,,0000,0000,0000,,I first heard these words\Nwhen I was just six years old,
Dialogue: 0,0:00:23.85,0:00:26.11,Default,,0000,0000,0000,,and I was completely inspired.
Dialogue: 0,0:00:26.13,0:00:28.51,Default,,0000,0000,0000,,I wanted to explore strange new worlds.
Dialogue: 0,0:00:28.53,0:00:30.03,Default,,0000,0000,0000,,I wanted to seek out new life.
Dialogue: 0,0:00:30.05,0:00:33.25,Default,,0000,0000,0000,,I wanted to see everything\Nthat the universe had to offer.
Dialogue: 0,0:00:34.33,0:00:38.03,Default,,0000,0000,0000,,And those dreams, those words,\Nthey took me on a journey,
Dialogue: 0,0:00:38.05,0:00:39.51,Default,,0000,0000,0000,,a journey of discovery,
Dialogue: 0,0:00:39.53,0:00:41.71,Default,,0000,0000,0000,,through school, through university,
Dialogue: 0,0:00:41.73,0:00:45.17,Default,,0000,0000,0000,,to do a PhD and finally\Nto become a professional astronomer.
Dialogue: 0,0:00:45.61,0:00:48.03,Default,,0000,0000,0000,,I learned that the reality was
Dialogue: 0,0:00:48.05,0:00:51.21,Default,,0000,0000,0000,,I wouldn't be piloting\Na starship anytime soon.
Dialogue: 0,0:00:52.45,0:00:57.07,Default,,0000,0000,0000,,But I also learned that the universe\Nis strange, wonderful and vast,
Dialogue: 0,0:00:57.09,0:00:59.89,Default,,0000,0000,0000,,actually too vast\Nto be explored by spaceship.
Dialogue: 0,0:01:00.73,0:01:04.09,Default,,0000,0000,0000,,And so I turned my attention\Nto astronomy, to using telescopes.
Dialogue: 0,0:01:04.85,0:01:07.63,Default,,0000,0000,0000,,Now, I show you before you\Nan image of the night sky.
Dialogue: 0,0:01:07.65,0:01:09.57,Default,,0000,0000,0000,,You might see it anywhere in the world.
Dialogue: 0,0:01:10.22,0:01:14.01,Default,,0000,0000,0000,,And all of these stars are part\Nof our local galaxy, the Milky Way.
Dialogue: 0,0:01:14.57,0:01:17.20,Default,,0000,0000,0000,,If you were to go\Nto a darker part of the sky,
Dialogue: 0,0:01:17.23,0:01:19.52,Default,,0000,0000,0000,,a nice dark site, perhaps in the desert,
Dialogue: 0,0:01:19.55,0:01:21.99,Default,,0000,0000,0000,,you might see the center\Nof our Milky Way galaxy
Dialogue: 0,0:01:22.01,0:01:24.65,Default,,0000,0000,0000,,spread out before you,\Nhundreds of billions of stars.
Dialogue: 0,0:01:25.54,0:01:27.12,Default,,0000,0000,0000,,And it's a very beautiful image.
Dialogue: 0,0:01:27.14,0:01:28.29,Default,,0000,0000,0000,,It's colorful.
Dialogue: 0,0:01:28.32,0:01:31.03,Default,,0000,0000,0000,,And again, this is just\Na local corner of our universe.
Dialogue: 0,0:01:31.43,0:01:34.52,Default,,0000,0000,0000,,You can see there's\Na sort of strange dark dust across it.
Dialogue: 0,0:01:34.55,0:01:36.27,Default,,0000,0000,0000,,Now, that is local dust
Dialogue: 0,0:01:36.29,0:01:38.95,Default,,0000,0000,0000,,that's obscuring the light of the stars.
Dialogue: 0,0:01:38.97,0:01:40.55,Default,,0000,0000,0000,,But we can do a pretty good job.
Dialogue: 0,0:01:40.57,0:01:44.03,Default,,0000,0000,0000,,Just with our own eyes, we can explore\Nour little corner of the universe.
Dialogue: 0,0:01:44.05,0:01:45.39,Default,,0000,0000,0000,,It's possible to do better.
Dialogue: 0,0:01:45.41,0:01:49.17,Default,,0000,0000,0000,,You can use wonderful telescopes\Nlike the Hubble Space Telescope.
Dialogue: 0,0:01:49.73,0:01:51.91,Default,,0000,0000,0000,,Now, astronomers\Nhave put together this image.
Dialogue: 0,0:01:51.93,0:01:53.83,Default,,0000,0000,0000,,It's called the Hubble Deep Field,
Dialogue: 0,0:01:53.85,0:01:58.19,Default,,0000,0000,0000,,and they've spent hundreds of hours\Nobserving just a tiny patch of the sky
Dialogue: 0,0:01:58.21,0:02:00.61,Default,,0000,0000,0000,,no larger than your thumbnail\Nheld at arm's length.
Dialogue: 0,0:02:01.05,0:02:02.31,Default,,0000,0000,0000,,And in this image
Dialogue: 0,0:02:02.33,0:02:03.99,Default,,0000,0000,0000,,you can see thousands of galaxies,
Dialogue: 0,0:02:04.01,0:02:07.47,Default,,0000,0000,0000,,and we know that there must be\Nhundreds of millions, billions of galaxies
Dialogue: 0,0:02:07.49,0:02:08.87,Default,,0000,0000,0000,,in the entire universe,
Dialogue: 0,0:02:08.89,0:02:11.55,Default,,0000,0000,0000,,some like our own and some very different.
Dialogue: 0,0:02:11.57,0:02:14.23,Default,,0000,0000,0000,,So you think, OK, well,\NI can continue this journey.
Dialogue: 0,0:02:14.25,0:02:16.95,Default,,0000,0000,0000,,This is easy. I can just\Nuse a very powerful telescope
Dialogue: 0,0:02:16.97,0:02:18.77,Default,,0000,0000,0000,,and just look at the sky, no problem.
Dialogue: 0,0:02:19.29,0:02:22.89,Default,,0000,0000,0000,,It's actually really missing out\Nif we just do that.
Dialogue: 0,0:02:22.91,0:02:25.65,Default,,0000,0000,0000,,Now, that's because\Neverything I've talked about so far
Dialogue: 0,0:02:25.67,0:02:29.57,Default,,0000,0000,0000,,is just using the visible spectrum,\Njust the thing that your eyes can see,
Dialogue: 0,0:02:29.59,0:02:32.95,Default,,0000,0000,0000,,and that's a tiny, tiny slice\Nof what the universe has to offer us.
Dialogue: 0,0:02:33.92,0:02:38.15,Default,,0000,0000,0000,,There's also two very important\Nproblems with using visible light.
Dialogue: 0,0:02:38.85,0:02:41.73,Default,,0000,0000,0000,,The first is that dust\Nthat I mentioned earlier.
Dialogue: 0,0:02:41.75,0:02:44.69,Default,,0000,0000,0000,,The dust stops the visible light\Nfrom getting to us.
Dialogue: 0,0:02:44.71,0:02:49.40,Default,,0000,0000,0000,,So as we look deeper\Ninto the universe, we see less light.
Dialogue: 0,0:02:49.42,0:02:52.84,Default,,0000,0000,0000,,But there's a really strange problem\Nwith using visible light
Dialogue: 0,0:02:52.86,0:02:54.100,Default,,0000,0000,0000,,in order to try and explore the universe.
Dialogue: 0,0:02:55.02,0:02:57.70,Default,,0000,0000,0000,,Say you're standing on a corner,\Na busy street corner.
Dialogue: 0,0:02:58.18,0:02:59.68,Default,,0000,0000,0000,,There's cars going by.
Dialogue: 0,0:02:59.70,0:03:01.10,Default,,0000,0000,0000,,An ambulance approaches.
Dialogue: 0,0:03:01.94,0:03:03.32,Default,,0000,0000,0000,,It has a high-pitched siren.
Dialogue: 0,0:03:03.34,0:03:07.08,Default,,0000,0000,0000,,(Imitates a siren passing by)
Dialogue: 0,0:03:07.10,0:03:09.44,Default,,0000,0000,0000,,The siren appeared to change in pitch
Dialogue: 0,0:03:09.46,0:03:11.54,Default,,0000,0000,0000,,as it moved towards and away from you.
Dialogue: 0,0:03:12.06,0:03:15.94,Default,,0000,0000,0000,,The ambulance driver did not change\Nthe siren just to mess with you.
Dialogue: 0,0:03:16.86,0:03:19.44,Default,,0000,0000,0000,,That was a product of your perception.
Dialogue: 0,0:03:19.46,0:03:22.20,Default,,0000,0000,0000,,The sound waves,\Nas the ambulance approached,
Dialogue: 0,0:03:22.22,0:03:23.44,Default,,0000,0000,0000,,were compressed,
Dialogue: 0,0:03:23.46,0:03:25.40,Default,,0000,0000,0000,,and they changed higher in pitch.
Dialogue: 0,0:03:25.42,0:03:28.20,Default,,0000,0000,0000,,As the ambulance receded,\Nthe sound waves were stretched,
Dialogue: 0,0:03:28.22,0:03:30.28,Default,,0000,0000,0000,,and they sounded lower in pitch.
Dialogue: 0,0:03:30.30,0:03:32.30,Default,,0000,0000,0000,,The same thing happens with light.
Dialogue: 0,0:03:32.86,0:03:35.24,Default,,0000,0000,0000,,Objects moving towards us,
Dialogue: 0,0:03:35.26,0:03:38.44,Default,,0000,0000,0000,,their light waves are compressed\Nand they appear bluer.
Dialogue: 0,0:03:38.46,0:03:40.68,Default,,0000,0000,0000,,Objects moving away from us,
Dialogue: 0,0:03:40.70,0:03:43.36,Default,,0000,0000,0000,,their light waves are stretched,\Nand they appear redder.
Dialogue: 0,0:03:43.38,0:03:46.26,Default,,0000,0000,0000,,So we call these effects\Nblueshift and redshift.
Dialogue: 0,0:03:47.26,0:03:49.24,Default,,0000,0000,0000,,Our universe is expanding,
Dialogue: 0,0:03:49.26,0:03:53.36,Default,,0000,0000,0000,,so everything is moving away\Nfrom everything else,
Dialogue: 0,0:03:53.38,0:03:56.06,Default,,0000,0000,0000,,and that means\Neverything appears to be red.
Dialogue: 0,0:03:56.97,0:04:00.56,Default,,0000,0000,0000,,And oddly enough, as you look\Nmore deeply into the universe,
Dialogue: 0,0:04:00.58,0:04:04.88,Default,,0000,0000,0000,,more distant objects\Nare moving away further and faster,
Dialogue: 0,0:04:04.90,0:04:06.62,Default,,0000,0000,0000,,so they appear more red.
Dialogue: 0,0:04:07.34,0:04:10.64,Default,,0000,0000,0000,,So if I come back to the Hubble Deep Field
Dialogue: 0,0:04:10.66,0:04:13.36,Default,,0000,0000,0000,,and we were to continue\Nto peer deeply into the universe
Dialogue: 0,0:04:13.38,0:04:14.92,Default,,0000,0000,0000,,just using the Hubble,
Dialogue: 0,0:04:14.94,0:04:17.64,Default,,0000,0000,0000,,as we get to a certain distance away,
Dialogue: 0,0:04:17.66,0:04:19.26,Default,,0000,0000,0000,,everything becomes red,
Dialogue: 0,0:04:20.06,0:04:22.04,Default,,0000,0000,0000,,and that presents something of a problem.
Dialogue: 0,0:04:22.06,0:04:24.12,Default,,0000,0000,0000,,Eventually, we get so far away
Dialogue: 0,0:04:24.14,0:04:27.12,Default,,0000,0000,0000,,everything is shifted into the infrared
Dialogue: 0,0:04:27.14,0:04:28.88,Default,,0000,0000,0000,,and we can't see anything at all.
Dialogue: 0,0:04:28.90,0:04:30.60,Default,,0000,0000,0000,,So there must be a way around this.
Dialogue: 0,0:04:30.62,0:04:32.44,Default,,0000,0000,0000,,Otherwise, I'm limited in my journey.
Dialogue: 0,0:04:32.46,0:04:34.36,Default,,0000,0000,0000,,I wanted to explore the whole universe,
Dialogue: 0,0:04:34.38,0:04:38.11,Default,,0000,0000,0000,,not just whatever I can see,\Nyou know, before the redshift kicks in.
Dialogue: 0,0:04:38.13,0:04:39.39,Default,,0000,0000,0000,,There is a technique.
Dialogue: 0,0:04:39.41,0:04:40.79,Default,,0000,0000,0000,,It's called radio astronomy.
Dialogue: 0,0:04:40.81,0:04:43.15,Default,,0000,0000,0000,,Astronomers have been\Nusing this for decades.
Dialogue: 0,0:04:43.17,0:04:44.47,Default,,0000,0000,0000,,It's a fantastic technique.
Dialogue: 0,0:04:44.49,0:04:47.99,Default,,0000,0000,0000,,I show you the Parkes Radio Telescope,\Naffectionately known as "The Dish."
Dialogue: 0,0:04:48.01,0:04:49.39,Default,,0000,0000,0000,,You may have seen the movie.
Dialogue: 0,0:04:49.41,0:04:50.89,Default,,0000,0000,0000,,And radio is really brilliant.
Dialogue: 0,0:04:50.91,0:04:53.45,Default,,0000,0000,0000,,It allows us to peer much more deeply.
Dialogue: 0,0:04:53.47,0:04:55.67,Default,,0000,0000,0000,,It doesn't get stopped by dust,
Dialogue: 0,0:04:55.69,0:04:57.95,Default,,0000,0000,0000,,so you can see everything in the universe,
Dialogue: 0,0:04:57.97,0:04:59.83,Default,,0000,0000,0000,,and redshift is less of a problem
Dialogue: 0,0:04:59.85,0:05:03.05,Default,,0000,0000,0000,,because we can build receivers\Nthat receive across a large band.
Dialogue: 0,0:05:03.57,0:05:07.51,Default,,0000,0000,0000,,So what does Parkes see when we turn it\Nto the center of the Milky Way?
Dialogue: 0,0:05:07.53,0:05:09.49,Default,,0000,0000,0000,,We should see something fantastic, right?
Dialogue: 0,0:05:10.13,0:05:13.03,Default,,0000,0000,0000,,Well, we do see something interesting.
Dialogue: 0,0:05:13.05,0:05:14.71,Default,,0000,0000,0000,,All that dust has gone.
Dialogue: 0,0:05:14.73,0:05:18.17,Default,,0000,0000,0000,,As I mentioned, radio goes\Nstraight through dust, so not a problem.
Dialogue: 0,0:05:18.81,0:05:20.71,Default,,0000,0000,0000,,But the view is very different.
Dialogue: 0,0:05:20.73,0:05:24.55,Default,,0000,0000,0000,,We can see that the center\Nof the Milky Way is aglow,
Dialogue: 0,0:05:24.57,0:05:26.25,Default,,0000,0000,0000,,and this isn't starlight.
Dialogue: 0,0:05:26.93,0:05:30.07,Default,,0000,0000,0000,,This is a light called\Nsynchrotron radiation,
Dialogue: 0,0:05:30.09,0:05:34.69,Default,,0000,0000,0000,,and it's formed from electrons\Nspiraling around cosmic magnetic fields.
Dialogue: 0,0:05:35.00,0:05:37.60,Default,,0000,0000,0000,,The plane is aglow with this light.
Dialogue: 0,0:05:37.62,0:05:40.92,Default,,0000,0000,0000,,And we can also see\Nstrange tufts coming off of it,
Dialogue: 0,0:05:40.94,0:05:43.44,Default,,0000,0000,0000,,and objects which don't appear to line up
Dialogue: 0,0:05:43.46,0:05:45.78,Default,,0000,0000,0000,,with anything that we can see\Nwith our own eyes.
Dialogue: 0,0:05:46.74,0:05:48.88,Default,,0000,0000,0000,,But it's hard to really\Ninterpret this image,
Dialogue: 0,0:05:48.90,0:05:51.68,Default,,0000,0000,0000,,because as you can see,\Nit's very low resolution.
Dialogue: 0,0:05:51.70,0:05:53.88,Default,,0000,0000,0000,,Radio waves have a wavelength that's long,
Dialogue: 0,0:05:53.90,0:05:56.20,Default,,0000,0000,0000,,and that makes their resolution poorer.
Dialogue: 0,0:05:56.22,0:05:58.19,Default,,0000,0000,0000,,This image is also black and white,
Dialogue: 0,0:05:58.21,0:06:01.97,Default,,0000,0000,0000,,so we don't really know\Nwhat is the color of everything in here.
Dialogue: 0,0:06:02.86,0:06:04.24,Default,,0000,0000,0000,,Well, fast-forward to today.
Dialogue: 0,0:06:04.26,0:06:05.72,Default,,0000,0000,0000,,We can build telescopes
Dialogue: 0,0:06:05.74,0:06:08.27,Default,,0000,0000,0000,,which can get over these problems.
Dialogue: 0,0:06:08.29,0:06:11.63,Default,,0000,0000,0000,,Now, I'm showing you here an image\Nof the Murchison Radio Observatory,
Dialogue: 0,0:06:11.65,0:06:14.43,Default,,0000,0000,0000,,a fantastic place\Nto build radio telescopes.
Dialogue: 0,0:06:14.45,0:06:16.75,Default,,0000,0000,0000,,It's flat, it's dry,
Dialogue: 0,0:06:16.77,0:06:19.75,Default,,0000,0000,0000,,and most importantly, it's radio quiet:
Dialogue: 0,0:06:19.77,0:06:22.87,Default,,0000,0000,0000,,no mobile phones, no Wi-Fi, nothing,
Dialogue: 0,0:06:22.89,0:06:25.39,Default,,0000,0000,0000,,just very, very radio quiet,
Dialogue: 0,0:06:25.41,0:06:28.13,Default,,0000,0000,0000,,so a perfect place\Nto build a radio telescope.
Dialogue: 0,0:06:29.01,0:06:31.87,Default,,0000,0000,0000,,The telescope that I've been\Nworking on for a few years
Dialogue: 0,0:06:31.89,0:06:33.83,Default,,0000,0000,0000,,is called the Murchison Widefield Array,
Dialogue: 0,0:06:33.85,0:06:36.87,Default,,0000,0000,0000,,and I'm going to show you\Na little time lapse of it being built.
Dialogue: 0,0:06:36.89,0:06:40.15,Default,,0000,0000,0000,,This is a group of undergraduate\Nand postgraduate students
Dialogue: 0,0:06:40.17,0:06:41.43,Default,,0000,0000,0000,,located in Perth.
Dialogue: 0,0:06:41.45,0:06:43.04,Default,,0000,0000,0000,,We call them the Student Army,
Dialogue: 0,0:06:43.07,0:06:45.88,Default,,0000,0000,0000,,and they volunteered their time\Nto build a radio telescope.
Dialogue: 0,0:06:45.91,0:06:47.55,Default,,0000,0000,0000,,There's no course credit for this.
Dialogue: 0,0:06:48.30,0:06:51.20,Default,,0000,0000,0000,,And they're putting together\Nthese radio dipoles.
Dialogue: 0,0:06:51.22,0:06:56.18,Default,,0000,0000,0000,,They just receive at low frequencies,\Na bit like your FM radio or your TV.
Dialogue: 0,0:06:56.98,0:07:00.08,Default,,0000,0000,0000,,And here we are deploying them\Nacross the desert.
Dialogue: 0,0:07:00.10,0:07:02.52,Default,,0000,0000,0000,,The final telescope\Ncovers 10 square kilometers
Dialogue: 0,0:07:02.54,0:07:04.68,Default,,0000,0000,0000,,of the Western Australian desert.
Dialogue: 0,0:07:04.70,0:07:07.62,Default,,0000,0000,0000,,And the interesting thing is,\Nthere's no moving parts.
Dialogue: 0,0:07:07.64,0:07:09.90,Default,,0000,0000,0000,,We just deploy these little antennas
Dialogue: 0,0:07:09.92,0:07:11.78,Default,,0000,0000,0000,,essentially on chicken mesh.
Dialogue: 0,0:07:11.80,0:07:13.28,Default,,0000,0000,0000,,It's fairly cheap.
Dialogue: 0,0:07:13.30,0:07:15.28,Default,,0000,0000,0000,,Cables take the signals
Dialogue: 0,0:07:15.30,0:07:16.94,Default,,0000,0000,0000,,from the antennas
Dialogue: 0,0:07:16.96,0:07:19.52,Default,,0000,0000,0000,,and bring them\Nto central processing units.
Dialogue: 0,0:07:19.54,0:07:21.32,Default,,0000,0000,0000,,And it's the size of this telescope,
Dialogue: 0,0:07:21.34,0:07:23.100,Default,,0000,0000,0000,,the fact that we've built it\Nover the entire desert
Dialogue: 0,0:07:24.02,0:07:26.82,Default,,0000,0000,0000,,that gives us a better\Nresolution than Parkes.
Dialogue: 0,0:07:27.46,0:07:30.100,Default,,0000,0000,0000,,Now, eventually all those cables\Nbring them to a unit
Dialogue: 0,0:07:31.02,0:07:34.56,Default,,0000,0000,0000,,which sends it off\Nto a supercomputer here in Perth,
Dialogue: 0,0:07:34.58,0:07:35.88,Default,,0000,0000,0000,,and that's where I come in.
Dialogue: 0,0:07:35.90,0:07:37.05,Default,,0000,0000,0000,,(Sighs)
Dialogue: 0,0:07:37.08,0:07:38.36,Default,,0000,0000,0000,,Radio data.
Dialogue: 0,0:07:38.38,0:07:40.40,Default,,0000,0000,0000,,I have spent the last five years
Dialogue: 0,0:07:40.42,0:07:43.28,Default,,0000,0000,0000,,working with very difficult,\Nvery interesting data
Dialogue: 0,0:07:43.30,0:07:45.28,Default,,0000,0000,0000,,that no one had really looked at before.
Dialogue: 0,0:07:45.30,0:07:47.44,Default,,0000,0000,0000,,I've spent a long time calibrating it,
Dialogue: 0,0:07:47.46,0:07:50.68,Default,,0000,0000,0000,,running millions of CPU hours\Non supercomputers
Dialogue: 0,0:07:50.70,0:07:52.93,Default,,0000,0000,0000,,and really trying to understand that data.
Dialogue: 0,0:07:52.95,0:07:54.10,Default,,0000,0000,0000,,With this data,
Dialogue: 0,0:07:54.12,0:07:58.15,Default,,0000,0000,0000,,we've performed a survey\Nof the entire southern sky,
Dialogue: 0,0:07:58.17,0:08:03.29,Default,,0000,0000,0000,,the GaLactic and Extragalactic\NAll-sky MWA Survey,
Dialogue: 0,0:08:03.31,0:08:04.82,Default,,0000,0000,0000,,or GLEAM, as I call it.
Dialogue: 0,0:08:05.26,0:08:07.16,Default,,0000,0000,0000,,Imagine you went to the Murchison,
Dialogue: 0,0:08:07.18,0:08:09.08,Default,,0000,0000,0000,,you camped out underneath the stars
Dialogue: 0,0:08:09.10,0:08:10.72,Default,,0000,0000,0000,,and you looked towards the south.
Dialogue: 0,0:08:10.74,0:08:12.41,Default,,0000,0000,0000,,You saw the south's celestial pole,
Dialogue: 0,0:08:12.43,0:08:13.64,Default,,0000,0000,0000,,the galaxy rising.
Dialogue: 0,0:08:13.66,0:08:16.28,Default,,0000,0000,0000,,If I fade in the radio light,
Dialogue: 0,0:08:16.30,0:08:18.96,Default,,0000,0000,0000,,this is what we observe with our survey.
Dialogue: 0,0:08:18.98,0:08:22.04,Default,,0000,0000,0000,,You can see that the galactic plane\Nis no longer dark with dust.
Dialogue: 0,0:08:22.06,0:08:24.37,Default,,0000,0000,0000,,It's alight with synchrotron radiation,
Dialogue: 0,0:08:24.39,0:08:25.64,Default,,0000,0000,0000,,and thousands of dots --
Dialogue: 0,0:08:25.66,0:08:28.96,Default,,0000,0000,0000,,our large Magellanic Cloud,\Nour nearest galactic neighbor,
Dialogue: 0,0:08:28.98,0:08:32.20,Default,,0000,0000,0000,,is orange instead\Nof its more familiar blue-white.
Dialogue: 0,0:08:32.22,0:08:35.60,Default,,0000,0000,0000,,So there's a lot going on in this.\NLet's take a closer look.
Dialogue: 0,0:08:35.62,0:08:38.04,Default,,0000,0000,0000,,If we look back\Ntowards the galactic center,
Dialogue: 0,0:08:38.06,0:08:41.28,Default,,0000,0000,0000,,where we originally saw the Parkes image\Nthat I showed you earlier,
Dialogue: 0,0:08:41.30,0:08:43.68,Default,,0000,0000,0000,,low resolution, black and white,
Dialogue: 0,0:08:43.70,0:08:46.25,Default,,0000,0000,0000,,and we fade to the GLEAM view,
Dialogue: 0,0:08:46.27,0:08:50.13,Default,,0000,0000,0000,,you can see the resolution\Nhas gone up by a factor of a hundred.
Dialogue: 0,0:08:50.15,0:08:53.01,Default,,0000,0000,0000,,We now have a color view of the sky,
Dialogue: 0,0:08:53.03,0:08:54.37,Default,,0000,0000,0000,,a technicolor view.
Dialogue: 0,0:08:54.39,0:08:57.37,Default,,0000,0000,0000,,Now, it's not a false color view.
Dialogue: 0,0:08:57.39,0:08:59.79,Default,,0000,0000,0000,,These are real radio colors.
Dialogue: 0,0:09:00.67,0:09:03.49,Default,,0000,0000,0000,,What I've done is I've colored\Nthe lowest frequencies red
Dialogue: 0,0:09:03.51,0:09:05.13,Default,,0000,0000,0000,,and the highest frequencies blue,
Dialogue: 0,0:09:05.15,0:09:06.73,Default,,0000,0000,0000,,and the middle ones green.
Dialogue: 0,0:09:06.75,0:09:08.97,Default,,0000,0000,0000,,And that gives us this rainbow view.
Dialogue: 0,0:09:08.99,0:09:10.85,Default,,0000,0000,0000,,And this isn't just false color.
Dialogue: 0,0:09:10.87,0:09:13.81,Default,,0000,0000,0000,,The colors in this image\Ntell us about the physical processes
Dialogue: 0,0:09:13.83,0:09:15.07,Default,,0000,0000,0000,,going on in the universe.
Dialogue: 0,0:09:15.64,0:09:18.41,Default,,0000,0000,0000,,So for instance, if you look\Nalong the plane of the galaxy,
Dialogue: 0,0:09:18.43,0:09:19.89,Default,,0000,0000,0000,,it's alight with synchrotron,
Dialogue: 0,0:09:19.91,0:09:22.29,Default,,0000,0000,0000,,which is mostly reddish orange,
Dialogue: 0,0:09:22.31,0:09:25.43,Default,,0000,0000,0000,,but if we look very closely,\Nwe see little blue dots.
Dialogue: 0,0:09:25.99,0:09:27.57,Default,,0000,0000,0000,,Now, if we zoom in,
Dialogue: 0,0:09:27.59,0:09:30.13,Default,,0000,0000,0000,,these blue dots are ionized plasma
Dialogue: 0,0:09:30.15,0:09:31.79,Default,,0000,0000,0000,,around very bright stars,
Dialogue: 0,0:09:32.35,0:09:35.13,Default,,0000,0000,0000,,and what happens\Nis that they block the red light,
Dialogue: 0,0:09:35.15,0:09:36.79,Default,,0000,0000,0000,,so they appear blue.
Dialogue: 0,0:09:37.35,0:09:40.02,Default,,0000,0000,0000,,And these can tell us\Nabout these star-forming regions
Dialogue: 0,0:09:40.04,0:09:41.30,Default,,0000,0000,0000,,in our galaxy.
Dialogue: 0,0:09:41.32,0:09:42.94,Default,,0000,0000,0000,,And we just see them immediately.
Dialogue: 0,0:09:42.96,0:09:46.02,Default,,0000,0000,0000,,We look at the galaxy,\Nand the color tells us that they're there.
Dialogue: 0,0:09:46.04,0:09:47.62,Default,,0000,0000,0000,,You can see little soap bubbles,
Dialogue: 0,0:09:47.64,0:09:50.83,Default,,0000,0000,0000,,little circular images\Naround the galactic plane,
Dialogue: 0,0:09:50.86,0:09:52.86,Default,,0000,0000,0000,,and these are supernova remnants.
Dialogue: 0,0:09:53.58,0:09:55.28,Default,,0000,0000,0000,,When a star explodes,
Dialogue: 0,0:09:55.30,0:09:57.76,Default,,0000,0000,0000,,its outer shell is cast off
Dialogue: 0,0:09:57.78,0:10:01.08,Default,,0000,0000,0000,,and it travels outward into space\Ngathering up material,
Dialogue: 0,0:10:01.10,0:10:03.06,Default,,0000,0000,0000,,and it produces a little shell.
Dialogue: 0,0:10:03.78,0:10:07.16,Default,,0000,0000,0000,,It's been a long-standing\Nmystery to astronomers
Dialogue: 0,0:10:07.18,0:10:09.26,Default,,0000,0000,0000,,where all the supernova remnants are.
Dialogue: 0,0:10:09.94,0:10:14.28,Default,,0000,0000,0000,,We know that there must be a lot\Nof high-energy electrons in the plane
Dialogue: 0,0:10:14.30,0:10:16.96,Default,,0000,0000,0000,,to produce the synchrotron\Nradiation that we see,
Dialogue: 0,0:10:16.98,0:10:19.56,Default,,0000,0000,0000,,and we think they're produced\Nby supernova remnants,
Dialogue: 0,0:10:19.58,0:10:21.36,Default,,0000,0000,0000,,but there don't seem to be enough.
Dialogue: 0,0:10:21.38,0:10:25.28,Default,,0000,0000,0000,,Fortunately, GLEAM is really, really\Ngood at detecting supernova remnants.
Dialogue: 0,0:10:26.16,0:10:27.42,Default,,0000,0000,0000,,That's fine.
Dialogue: 0,0:10:27.44,0:10:29.44,Default,,0000,0000,0000,,We've explored our little local universe,
Dialogue: 0,0:10:29.46,0:10:31.84,Default,,0000,0000,0000,,but I wanted to go deeper,\NI wanted to go further.
Dialogue: 0,0:10:31.86,0:10:34.12,Default,,0000,0000,0000,,I wanted to go beyond the Milky Way.
Dialogue: 0,0:10:34.14,0:10:37.92,Default,,0000,0000,0000,,Well, as it happens, we can see a very\Ninteresting object in the top right,
Dialogue: 0,0:10:37.94,0:10:40.16,Default,,0000,0000,0000,,and this is a local radio galaxy,
Dialogue: 0,0:10:40.18,0:10:41.42,Default,,0000,0000,0000,,Centaurus A.
Dialogue: 0,0:10:41.86,0:10:43.01,Default,,0000,0000,0000,,If we zoom in on this,
Dialogue: 0,0:10:43.04,0:10:46.44,Default,,0000,0000,0000,,we can see that there are\Ntwo huge plumes going out into space.
Dialogue: 0,0:10:47.22,0:10:50.12,Default,,0000,0000,0000,,And if you look right in the center\Nbetween those two plumes,
Dialogue: 0,0:10:50.14,0:10:52.52,Default,,0000,0000,0000,,you'll see a galaxy just like our own.
Dialogue: 0,0:10:52.54,0:10:54.100,Default,,0000,0000,0000,,It's a spiral. It has a dust lane.
Dialogue: 0,0:10:55.02,0:10:56.64,Default,,0000,0000,0000,,It's a normal galaxy.
Dialogue: 0,0:10:56.66,0:10:59.68,Default,,0000,0000,0000,,But these jets\Nare only visible in the radio.
Dialogue: 0,0:10:59.70,0:11:02.88,Default,,0000,0000,0000,,If we looked in the visible,\Nwe wouldn't even know they were there,
Dialogue: 0,0:11:02.90,0:11:05.94,Default,,0000,0000,0000,,and they're thousands of times larger\Nthan the host galaxy.
Dialogue: 0,0:11:06.50,0:11:08.90,Default,,0000,0000,0000,,What's going on?\NWhat's producing these jets?
Dialogue: 0,0:11:10.18,0:11:13.72,Default,,0000,0000,0000,,At the center of every galaxy\Nthat we know about
Dialogue: 0,0:11:13.74,0:11:15.100,Default,,0000,0000,0000,,is a supermassive black hole.
Dialogue: 0,0:11:16.02,0:11:17.51,Default,,0000,0000,0000,,Now, black holes are invisible.
Dialogue: 0,0:11:18.06,0:11:21.08,Default,,0000,0000,0000,,All you can see is the deflection\Nof the light around them,
Dialogue: 0,0:11:21.10,0:11:25.40,Default,,0000,0000,0000,,and occasionally, when a star\Nor a cloud of gas comes into their orbit,
Dialogue: 0,0:11:25.42,0:11:28.16,Default,,0000,0000,0000,,it is ripped apart by tidal forces,
Dialogue: 0,0:11:28.18,0:11:30.66,Default,,0000,0000,0000,,forming what we call an accretion disk.
Dialogue: 0,0:11:31.26,0:11:34.48,Default,,0000,0000,0000,,The accretion disk\Nglows brightly in the x-rays,
Dialogue: 0,0:11:34.50,0:11:38.92,Default,,0000,0000,0000,,and huge magnetic fields\Ncan launch the material into space
Dialogue: 0,0:11:38.94,0:11:40.66,Default,,0000,0000,0000,,at nearly the speed of light.
Dialogue: 0,0:11:41.05,0:11:43.83,Default,,0000,0000,0000,,These jets are visible in the radio
Dialogue: 0,0:11:43.86,0:11:46.02,Default,,0000,0000,0000,,and this is what we pick up in our survey.
Dialogue: 0,0:11:46.66,0:11:49.44,Default,,0000,0000,0000,,Well, very well,\Nso we've seen one radio galaxy.
Dialogue: 0,0:11:49.46,0:11:51.64,Default,,0000,0000,0000,,But if you just look\Nat the top of that image,
Dialogue: 0,0:11:51.66,0:11:53.40,Default,,0000,0000,0000,,you'll see another radio galaxy.
Dialogue: 0,0:11:53.42,0:11:56.66,Default,,0000,0000,0000,,It's a little bit smaller,\Nand that's just because it's further away.
Dialogue: 0,0:11:57.15,0:11:59.84,Default,,0000,0000,0000,,OK. Two radio galaxies.
Dialogue: 0,0:11:59.86,0:12:01.33,Default,,0000,0000,0000,,We can see this. This is fine.
Dialogue: 0,0:12:01.36,0:12:03.10,Default,,0000,0000,0000,,Well, what about all the other dots?
Dialogue: 0,0:12:03.12,0:12:04.68,Default,,0000,0000,0000,,Presumably those are just stars.
Dialogue: 0,0:12:05.06,0:12:06.28,Default,,0000,0000,0000,,They're not.
Dialogue: 0,0:12:06.30,0:12:07.90,Default,,0000,0000,0000,,They're all radio galaxies.
Dialogue: 0,0:12:08.55,0:12:11.45,Default,,0000,0000,0000,,Every single one of the dots in this image
Dialogue: 0,0:12:11.47,0:12:13.15,Default,,0000,0000,0000,,is a distant galaxy,
Dialogue: 0,0:12:13.17,0:12:16.03,Default,,0000,0000,0000,,millions to billions of light-years away
Dialogue: 0,0:12:16.06,0:12:18.73,Default,,0000,0000,0000,,with a supermassive\Nblack hole at its center
Dialogue: 0,0:12:18.75,0:12:22.19,Default,,0000,0000,0000,,pushing material into space\Nat nearly the speed of light.
Dialogue: 0,0:12:22.21,0:12:23.71,Default,,0000,0000,0000,,It is mind-blowing.
Dialogue: 0,0:12:24.85,0:12:28.59,Default,,0000,0000,0000,,And this survey is even larger\Nthan what I've shown here.
Dialogue: 0,0:12:28.61,0:12:31.15,Default,,0000,0000,0000,,If we zoom out to\Nthe full extent of the survey,
Dialogue: 0,0:12:31.17,0:12:34.54,Default,,0000,0000,0000,,you can see I found 300,000\Nof these radio galaxies.
Dialogue: 0,0:12:35.14,0:12:37.24,Default,,0000,0000,0000,,We've discovered all of these galaxies
Dialogue: 0,0:12:37.27,0:12:40.83,Default,,0000,0000,0000,,right back to the very first\Nsupermassive black holes.
Dialogue: 0,0:12:41.68,0:12:44.64,Default,,0000,0000,0000,,There's something even more in this image.
Dialogue: 0,0:12:45.32,0:12:47.72,Default,,0000,0000,0000,,I'll take you right back\Nto the dawn of time.
Dialogue: 0,0:12:47.74,0:12:50.90,Default,,0000,0000,0000,,When the universe formed,\Nit was a big bang,
Dialogue: 0,0:12:50.92,0:12:54.82,Default,,0000,0000,0000,,which left the universe as a sea\Nof hydrogen, neutral hydrogen.
Dialogue: 0,0:12:54.84,0:12:57.62,Default,,0000,0000,0000,,And when the very first stars\Nand galaxies switched on,
Dialogue: 0,0:12:57.64,0:12:59.74,Default,,0000,0000,0000,,they ionized that hydrogen.
Dialogue: 0,0:12:59.76,0:13:03.20,Default,,0000,0000,0000,,So the universe went\Nfrom neutral to ionized.
Dialogue: 0,0:13:04.08,0:13:07.26,Default,,0000,0000,0000,,That imprinted a signal all around us.
Dialogue: 0,0:13:07.28,0:13:09.02,Default,,0000,0000,0000,,Everywhere, it pervades us,
Dialogue: 0,0:13:09.04,0:13:10.46,Default,,0000,0000,0000,,like the Force.
Dialogue: 0,0:13:10.49,0:13:11.49,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:13:11.52,0:13:14.36,Default,,0000,0000,0000,,Because that happened so long ago,
Dialogue: 0,0:13:14.92,0:13:16.72,Default,,0000,0000,0000,,the signal was redshifted,
Dialogue: 0,0:13:17.48,0:13:20.78,Default,,0000,0000,0000,,so now that signal\Nis at very low frequencies.
Dialogue: 0,0:13:20.80,0:13:23.26,Default,,0000,0000,0000,,It's at the same frequency as my survey,
Dialogue: 0,0:13:23.28,0:13:24.66,Default,,0000,0000,0000,,but it's so faint.
Dialogue: 0,0:13:24.68,0:13:28.56,Default,,0000,0000,0000,,It's a billionth the size\Nof any of the objects in my survey.
Dialogue: 0,0:13:29.24,0:13:33.87,Default,,0000,0000,0000,,So our telescope may not be quite\Nsensitive enough to pick up this signal.
Dialogue: 0,0:13:33.89,0:13:36.39,Default,,0000,0000,0000,,However, there's a new radio telescope.
Dialogue: 0,0:13:36.41,0:13:38.07,Default,,0000,0000,0000,,So I can't have a starship,
Dialogue: 0,0:13:38.09,0:13:39.35,Default,,0000,0000,0000,,but I can hopefully have
Dialogue: 0,0:13:39.37,0:13:42.23,Default,,0000,0000,0000,,one of the biggest\Nradio telescopes in the world.
Dialogue: 0,0:13:42.25,0:13:45.87,Default,,0000,0000,0000,,We're building the Square Kilometre Array,\Na new radio telescope,
Dialogue: 0,0:13:45.89,0:13:48.63,Default,,0000,0000,0000,,and it's going to be a thousand\Ntimes bigger than the MWA,
Dialogue: 0,0:13:48.65,0:13:51.87,Default,,0000,0000,0000,,a thousand times more sensitive,\Nand have an even better resolution.
Dialogue: 0,0:13:51.89,0:13:54.11,Default,,0000,0000,0000,,So we should find\Ntens of millions of galaxies.
Dialogue: 0,0:13:54.13,0:13:56.47,Default,,0000,0000,0000,,And perhaps, deep in that signal,
Dialogue: 0,0:13:56.49,0:14:00.67,Default,,0000,0000,0000,,I will get to look upon the very first\Nstars and galaxies switching on,
Dialogue: 0,0:14:00.69,0:14:03.05,Default,,0000,0000,0000,,the beginning of time itself.
Dialogue: 0,0:14:03.51,0:14:04.66,Default,,0000,0000,0000,,Thank you.
Dialogue: 0,0:14:04.69,0:14:11.69,Default,,0000,0000,0000,,(Applause)