We are made of star stuff | Jocelyn Bell Burnell | TEDxVienna
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0:19 - 0:24I have a slight problem,
but the show's going on. -
0:26 - 0:28My blood's red.
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0:29 - 0:31Is Viennese blood red?
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0:31 - 0:32(Laughter)
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0:32 - 0:34I suspect it is.
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0:37 - 0:39Why is blood red?
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0:40 - 0:43Does anybody know? Can you tell me?
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0:43 - 0:44(Audience) It's iron.
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0:44 - 0:46It's iron, yes.
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0:46 - 0:49It's iron in the hemoglobin,
in our bloodstream, -
0:50 - 0:52that makes the blood red.
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0:52 - 0:54Iron is one of the chemical elements,
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0:54 - 0:56and I'm going to talk
about that in a moment. -
0:56 - 0:58But, just first ...
-
0:58 - 1:00(Laughter)
-
1:00 - 1:02... tomato ketchup.
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1:02 - 1:05We'll hear more about tomatoes later.
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1:05 - 1:07(Laughter) (Applause)
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1:13 - 1:16Back to the chemical elements and iron.
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1:17 - 1:19It is, indeed,
one of the chemical elements, -
1:19 - 1:23and even if you're not a chemist,
you probably know of some others. -
1:26 - 1:29An answer given by a student in an exam.
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1:29 - 1:32[H2O is hot water and CO2 is cold water.]
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1:32 - 1:34(Laughter)
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1:39 - 1:41So, you know what H2O is?
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1:42 - 1:45(Audience) Water.
Jocelyn Burnell: Water. CO2? -
1:45 - 1:48(Audience) Carbon dioxide.
JB: Carbon dioxide. -
1:48 - 1:51So, we've got here
another three chemical elements: -
1:51 - 1:54hydrogen, oxygen, and carbon.
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1:55 - 1:57And while we're dealing
with student exam questions, -
1:57 - 1:59here's another one about water:
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2:00 - 2:02Water is composed of two gins ...
-
2:02 - 2:05[Water is composed of two gins,
Oxygin and Hydrogin.] -
2:05 - 2:07[Oxygin is pure gin.
Hydrogin is water and gin.] -
2:07 - 2:09(Laughter)
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2:15 - 2:19These answers come from
the United States of America, but ... -
2:19 - 2:22(Laughter) (Applause)
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2:26 - 2:31It's a wonderful resource of all sorts
of amazing things that come true. -
2:33 - 2:36Maybe some of you
recall seeing a diagram like this -
2:36 - 2:39in school chemistry laboratories.
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2:39 - 2:42You can see it in other places, too,
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2:42 - 2:47even these days on tea towels,
mugs, bags, pens. -
2:48 - 2:53It's a tabulation of the 100 plus
chemical elements that we know about. -
2:55 - 2:58In Oxford, where I come from,
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2:58 - 3:01we have it on taxis and buses, as well -
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3:01 - 3:03but that's Oxford.
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3:03 - 3:05(Laughter)
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3:06 - 3:11Now, in our bodies, there's clearly
iron in the bloodstream, -
3:11 - 3:16there's also hydrogen and oxygen
because we're two-thirds water. -
3:16 - 3:20There's carbon in our tissues,
calcium in our bones. -
3:23 - 3:26I'm going to focus on the iron
because this is a short talk. -
3:28 - 3:32Where did that iron, and, indeed,
where did those other things come from? -
3:32 - 3:35How did it get into our bodies?
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3:35 - 3:37It's not in the air ... much.
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3:39 - 3:42It's come through what we've eaten:
plants and animals. -
3:44 - 3:48How did the iron
get into the plants and animals? -
3:50 - 3:51Well, it came from the earth.
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3:52 - 3:54How did it get into the earth?
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3:54 - 3:56Where did it come from before that?
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3:58 - 4:00What I am going to be telling you about
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4:00 - 4:04is how the stars have created
the chemical elements - -
4:04 - 4:10the key ingredients of life:
oxygen, carbon, calcium, iron - -
4:10 - 4:12with particular emphasis on the iron.
-
4:14 - 4:18Stars are formed in some
of the dark spots of the galaxy, -
4:18 - 4:20the dark patches.
-
4:20 - 4:24There are particles
of gas and dust milling around, -
4:24 - 4:26by chance as a little knot,
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4:26 - 4:28it's got extra gravity,
pulls in some more, -
4:28 - 4:31puts up the gravity, pulls in more.
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4:31 - 4:34And over some millions of years,
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4:34 - 4:39this little knot grows into
what's going to be a full-blown star. -
4:40 - 4:43When the temperature
in the middle of this lump -
4:43 - 4:46reaches about 10 million degrees,
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4:46 - 4:48nuclear reactions start,
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4:48 - 4:54and, in particular, a nuclear reaction
of hydrogen being converted to helium. -
4:55 - 4:58And there's some energy to spare,
and it comes out of starlight. -
5:00 - 5:02Our sun's busy doing that:
-
5:02 - 5:08our sun is burning about 600 million
tons of hydrogen every second. -
5:09 - 5:11It's done that for 5 billion years.
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5:11 - 5:15It'll do it for about
another 5 billion years. -
5:16 - 5:22And shortly after that, it will end,
and it's actually no use for this story. -
5:22 - 5:24(Laughter)
-
5:24 - 5:27We have to focus
on a very small minority of stars, -
5:27 - 5:29the extremely massive ones,
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5:29 - 5:3310, 20, 30 times the size of our sun.
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5:34 - 5:37Examples of these that you might know:
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5:37 - 5:43the Pleiades - which is in the winter sky
near the constellation of Orion, -
5:43 - 5:44and Betelgeuse -
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5:44 - 5:49which is the reddish star,
top left in the constellation of Orion. -
5:50 - 5:54These big stars not only convert
hydrogen to helium, -
5:54 - 5:55but then the helium to carbon,
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5:55 - 6:00and work their way
across the periodic table -
6:00 - 6:03till they end up with iron
in the center of the core. -
6:03 - 6:08And this is the first place
that we have iron in the universe - -
6:08 - 6:10in the cores of some stars.
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6:12 - 6:16Not very useful to us
if it's in the cores of stars. -
6:18 - 6:24But star death, dramatic star death,
comes to the rescue. -
6:25 - 6:30A pair of photographs here:
a "before" and an "after." -
6:31 - 6:35We're looking at
a southern hemisphere object -
6:35 - 6:38called the Large Magellanic Cloud.
-
6:38 - 6:42It's a small galaxy,
external to ours, but quite nearby. -
6:43 - 6:46We're seeing up top left
a glowing mass of gas, -
6:47 - 6:49quite a lot of pink hydrogen gas,
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6:50 - 6:52millions of little stars,
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6:52 - 6:56and one of them, bottom right,
picked out with an arrow. -
6:57 - 7:00For those of you
who are not astrophysicists, -
7:00 - 7:03the arrow's added after the photo's taken.
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7:03 - 7:06(Laughter)
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7:08 - 7:14But, this inconspicuous star
that we had to pick out with an arrow -
7:14 - 7:15becomes this,
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7:16 - 7:20and you don't need an arrow
to see that thing in the bottom right. -
7:21 - 7:24The star has exploded catastrophically.
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7:25 - 7:27It was one of these big stars
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7:27 - 7:30like the ones in the Pleiades,
or Betelgeuse. -
7:30 - 7:34It's gone all the way through
the various chemical elements. -
7:34 - 7:38It's got this range of onion shells
with iron in the middle -
7:38 - 7:40and the other chemical
elements outside it, -
7:41 - 7:43and it has exploded.
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7:44 - 7:48The physics of the explosion
is quite complicated, -
7:48 - 7:50so I'm not going to go
into the details of that, -
7:50 - 7:53but it is a catastrophic explosion.
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7:54 - 7:57We used to assume
it was totally catastrophic. -
7:57 - 8:01We now know that the pulsars
that Vlad mentioned in his introduction -
8:01 - 8:05are formed from the cores
of these exploding stars. -
8:05 - 8:10But 95% of the star
is skooshed out into space, -
8:11 - 8:15which means that being
fanned out across space -
8:15 - 8:20are useful chemical elements
that were inside the star: -
8:20 - 8:24oxygen, calcium, carbon, iron,
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8:25 - 8:30spread out, made available
by the catastrophic terminal explosion -
8:30 - 8:32of this particular star.
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8:35 - 8:41Now, getting from there to us
is quite a long story, -
8:42 - 8:45and I'm going to do this bit by mime.
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8:46 - 8:48You've probably got some sense
-
8:48 - 8:52that physics professors
have a slightly dubious reputation. -
8:52 - 8:53(Laughter)
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8:53 - 8:56The female ones are utterly nuts!
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8:57 - 8:59And I'm just about to prove it!
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8:59 - 9:01(Applause)
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9:05 - 9:08So, this stage is the Milky Way -
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9:08 - 9:09our galaxy,
-
9:10 - 9:14and this is a story
that involves all the Milky Way. -
9:15 - 9:19Over here in the Milky Way
is one of these dark clouds -
9:19 - 9:21where stars sometimes form,
-
9:22 - 9:26particles of gas, molecules,
dust milling around. -
9:27 - 9:29By chance, there's a little knot,
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9:29 - 9:34it has extra gravity, it pulls in
some more bits of dust and gas, -
9:34 - 9:36puts up the mass, puts up the gravity,
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9:36 - 9:38pulls in some more bits.
-
9:40 - 9:44To save time, folks, this is going to be
one of these very massive stars, -
9:44 - 9:47otherwise we're here for a long time.
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9:48 - 9:51So, this gradually grows, gradually grows.
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9:52 - 9:55And at the point when it's grown so much
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9:55 - 9:59that the temperature in the middle
has reached about 10 million degrees, -
9:59 - 10:03it starts its sequence
of nuclear reactions, -
10:03 - 10:07and it burns, converts hydrogen to helium.
-
10:07 - 10:09Brrrr!
-
10:10 - 10:13Then it starts to run out
of hydrogen in its core. -
10:14 - 10:16So it starts converting helium to carbon.
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10:16 - 10:17Brrrr!
-
10:19 - 10:20That doesn't last as long.
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10:20 - 10:22Then it runs out of helium in its core,
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10:22 - 10:26so it converts carbon
to oxygen, oxygen ... -
10:26 - 10:28Brrr! Brr! Brr! Brr!
-
10:28 - 10:30Boom!
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10:30 - 10:32(Laughter)
-
10:33 - 10:38And millions and millions
and millions of tons of stuff, gas, -
10:38 - 10:41fan out from this explosion site
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10:42 - 10:44in one part of our Milky Way.
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10:47 - 10:49It percolates, slowly,
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10:49 - 10:53but we've got eons, there's no rush.
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10:53 - 10:54(Laughter)
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10:54 - 10:56It can travel,
-
10:56 - 10:59and it does travel,
gradually, in all directions, -
10:59 - 11:01but we're interested in this bit.
-
11:02 - 11:04And some comes over here
-
11:05 - 11:08to where there is another
of these dark clouds -
11:08 - 11:10with particles of gas
and dust milling around. -
11:11 - 11:15And some of the material
from that distant explosion -
11:15 - 11:17finds its way over here,
-
11:17 - 11:22and that material is rich
in carbon and calcium -
11:22 - 11:24and iron and oxygen, and so on.
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11:24 - 11:26So it joins this cloud,
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11:26 - 11:30and by chance a little knot forms,
it's got extra gravity, -
11:30 - 11:34pulls in some more particles,
puts up the mass, puts up the gravity, -
11:34 - 11:36pulls in some more particles,
-
11:36 - 11:38puts up the mass, puts up the gravity,
-
11:38 - 11:41and over a million years,
10 million years, -
11:41 - 11:43it grows and grows and grows.
-
11:44 - 11:47And once again,
I have to crave your indulgence, -
11:47 - 11:50could this also be
one of these big stars?-- -
11:51 - 11:53otherwise we're here all night.
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11:54 - 11:56So this big star grows,
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11:56 - 12:01and the nuclear reactions start,
and it burns, converts hydrogen to helium. -
12:01 - 12:02Brrrr!
-
12:03 - 12:05Runs out of hydrogen, burns helium. Brrrr!
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12:05 - 12:07Runs out of helium, burns carbon.
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12:07 - 12:09Brrr! Brr! Brr! Brr! Boom!
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12:09 - 12:10(Laughter)
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12:10 - 12:13Now, you know the next bit of the story.
-
12:13 - 12:17Millions and millions and millions
of tons of stuff fan out across space, -
12:18 - 12:21and some of it makes its way over here
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12:22 - 12:26to another dark part
of the galaxy - the Milky Way - -
12:27 - 12:30where there's a star beginning to form.
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12:30 - 12:33The material that comes from there
-
12:33 - 12:38is doubly enriched in carbon
and calcium and iron, and so on, -
12:38 - 12:41because of the stuff
that that star generated, -
12:41 - 12:43plus the stuff it got
from that star, as well. -
12:44 - 12:49So, what's arriving here
is double dose carbon, -
12:49 - 12:51calcium, iron, and so on.
-
12:52 - 12:57And here in this cloud,
a star called the Sun is forming, -
12:58 - 12:59and it's made from the stuff
-
12:59 - 13:01that happens to be
in this patch of the galaxy, -
13:01 - 13:04plus the stuff that's come from that star,
-
13:04 - 13:06plus the stuff
that's come direct from there, -
13:06 - 13:09and maybe from some other
exploding stars, as well. -
13:10 - 13:13Our sun is a third-generation star.
-
13:14 - 13:17Our star is a late-forming star,
-
13:17 - 13:19and it has to be
-
13:20 - 13:21or we wouldn't be here.
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13:22 - 13:28We can only exist close to a young star
-
13:28 - 13:32that's been enriched
by previous solar cycles. -
13:33 - 13:35So, the sun forms,
-
13:35 - 13:37some of the material is left over.
-
13:39 - 13:41You've perhaps seen pictures
of the planet Saturn -
13:41 - 13:43with its rings around it.
-
13:43 - 13:45This is a giant version of that.
-
13:46 - 13:48So you've got a sun
-
13:48 - 13:51and some of the debris
in a giant ring around it. -
13:52 - 13:54Let's focus on the debris -
-
13:55 - 13:56little bits going around.
-
13:56 - 13:59Little bits occasionally collide
with other bits, -
13:59 - 14:02and they go around
and collide with other bits -
14:02 - 14:04and go around.
-
14:04 - 14:08And ultimately, you end up with planets
-
14:08 - 14:11and the ring, the rest
of the ring has disappeared. -
14:12 - 14:15The planets are made
of the same stuff as the sun, -
14:15 - 14:17which, you remember,
is made of the stuff that was here, -
14:17 - 14:19plus stuff from there,
plus stuff from there. -
14:22 - 14:24It makes eight planets,
-
14:24 - 14:26not Pluto.
-
14:26 - 14:28(Laughter)
-
14:29 - 14:31Pluto was grabbed later.
-
14:32 - 14:35You can think of Pluto
as an adopted child, if you wish. -
14:36 - 14:37The rest are birth children.
-
14:39 - 14:43So, these planets are basically
made of the same stuff as the sun, -
14:44 - 14:47which is made up of stuff that was here,
-
14:47 - 14:53plus debris from exploding stars
actually all over our galaxy. -
14:53 - 14:55It's not that we can say,
"It was that one and that one." -
14:55 - 14:58It's that one and that one
and that one and that one -
14:58 - 15:00and that one and that one
and that one and that one - -
15:01 - 15:04doubly enriched with all
these useful chemical elements. -
15:04 - 15:08And the planets, likewise,
are of the same stuff. -
15:08 - 15:10There has been some change
-
15:10 - 15:13in that the planets
closest to the sun got hot, -
15:13 - 15:17and the material that most easily
evaporates has boiled off. -
15:17 - 15:21Further out, you can see
the original composition rather better. -
15:22 - 15:24But that's broadly what has happened.
-
15:25 - 15:31So we who eat the plants and the animals
that absorb elements from the earth, -
15:32 - 15:35we are made
of the same stuff as the earth, -
15:35 - 15:38and the earth is made
of the same stuff as the sun, -
15:38 - 15:42which is made up
of the rest of the galaxy. -
15:43 - 15:48So, iron was created
in those very massive stars, -
15:48 - 15:52ones that went through
lots of nuclear reactions. -
15:53 - 15:55And that iron was made available
-
15:55 - 15:59by the catastrophic death
of those big stars. -
16:00 - 16:02So there's life and death already.
-
16:04 - 16:08If it wasn't for those stars,
particularly the ones that had died, -
16:08 - 16:10we would not be here.
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16:11 - 16:14And we're intimately and ultimately
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16:14 - 16:16children of the stars,
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16:17 - 16:20to such an extent that, actually,
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16:20 - 16:22we are stars.
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16:23 - 16:24Thank you.
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16:24 - 16:27(Applause)
- Title:
- We are made of star stuff | Jocelyn Bell Burnell | TEDxVienna
- Description:
-
Jocelyn Bell Burnell is a Visiting Professor in Oxford (UK). She inadvertently discovered pulsars as a graduate student in radio astronomy in Cambridge, opening up a new branch of astrophysics - work recognised by the award of a Nobel Prize to her supervisor. Subsequently she has worked in many roles in many branches of astronomy, working part-time while raising a family. Increasing the number of women in science is important to her. In her spare time she gardens, listens to choral music, collects poetry with an astronomical theme, and is active in the Quakers (Religious Society of Friends).
This talk was given at a TEDx event using the TED conference format but inde-pendently organized by a local community. Learn more at http://ted.com/tedx
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDxTalks
- Duration:
- 16:43
Theresa Ranft approved English subtitles for We are made of star stuff | Jocelyn Bell Burnell | TEDxVienna | ||
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Theresa Ranft edited English subtitles for We are made of star stuff | Jocelyn Bell Burnell | TEDxVienna | ||
Theresa Ranft edited English subtitles for We are made of star stuff | Jocelyn Bell Burnell | TEDxVienna | ||
Theresa Ranft edited English subtitles for We are made of star stuff | Jocelyn Bell Burnell | TEDxVienna | ||
Theresa Ranft edited English subtitles for We are made of star stuff | Jocelyn Bell Burnell | TEDxVienna |